Stratix 器件手册,第 2 卷
Stratix Device Handbook, Volume 2
101 Innovation Drive
San Jose, CA 95134
(408) 544-7000
http://www.altera.com
S5V2-3.5
Copyright © 2006 Altera Corporation. All rights reserved. Altera, The Programmable Solutions Company, the stylized Altera logo, specific device designations, and all other words and logos that are identified as trademarks and/or service marks are, unless noted otherwise, the trademarks and
service marks of Altera Corporation in the U.S. and other countries. All other product or service names are the property of their respective holders. Altera products are protected under numerous U.S. and foreign patents and pending applications, maskwork rights, and copyrights. Altera warrants
performance of its semiconductor products to current specifications in accordance with Altera's standard warranty, but reserves the right to make
changes to any products and services at any time without notice. Altera assumes no responsibility or liability arising out of the application or use of any information, product, or service described herein except as
expressly agreed to in writing by Altera Corporation. Altera customers are advised to obtain the latest version of device specifications before relying on any published information and before placing orders for
products or services.
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Contents
Chapter Revision Dates ......................................................................... xiii
About This Handbook ............................................................................. xv
How to Find Information ...................................................................................................................... xv
How to Contact Altera ........................................................................................................................... xv
Typographic Conventions .................................................................................................................... xvi
Section I. Clock Management
Revision History ....................................................................................................................... Section I–1
Chapter 1. General-Purpose PLLs in Stratix & Stratix GX Devices
Introduction ............................................................................................................................................ 1–1
Enhanced PLLs ....................................................................................................................................... 1–5
Clock Multiplication & Division .................................................................................................... 1–9
External Clock Outputs ................................................................................................................. 1–10
Clock Feedback ............................................................................................................................... 1–14
Phase Shifting ................................................................................................................................. 1–14
Lock Detect ...................................................................................................................................... 1–15
Programmable Duty Cycle ........................................................................................................... 1–16
General Advanced Clear & Enable Control ............................................................................... 1–16
Programmable Bandwidth ............................................................................................................ 1–18
Clock Switchover ............................................................................................................................ 1–25
Spread-Spectrum Clocking ........................................................................................................... 1–25
PLL Reconfiguration ...................................................................................................................... 1–30
Enhanced PLL Pins ........................................................................................................................ 1–30
Fast PLLs ............................................................................................................................................... 1–31
Clock Multiplication & Division .................................................................................................. 1–34
External Clock Outputs ................................................................................................................. 1–34
Phase Shifting ................................................................................................................................. 1–35
Programmable Duty Cycle ........................................................................................................... 1–36
Control Signals ................................................................................................................................ 1–36
Pins ................................................................................................................................................... 1–37
Clocking ................................................................................................................................................ 1–39
Global & Hierarchical Clocking ................................................................................................... 1–39
Clock Input Connections ............................................................................................................... 1–41
Clock Output Connections ............................................................................................................ 1–43
Board Layout ........................................................................................................................................ 1–50
VCCA & GNDA ............................................................................................................................. 1–50
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VCCG & GNDG ..............................................................................................................................
External Clock Output Power ......................................................................................................
Guidelines ........................................................................................................................................
Conclusion ............................................................................................................................................
1–52
1–53
1–56
1–56
Section II. Memory
Revision History ..................................................................................................................... Section II–1
Chapter 2. TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Introduction ............................................................................................................................................ 2–1
TriMatrix Memory ................................................................................................................................. 2–1
Clear Signals ...................................................................................................................................... 2–3
Parity Bit Support ............................................................................................................................. 2–3
Byte Enable Support ........................................................................................................................ 2–4
Using TriMatrix Memory ..................................................................................................................... 2–7
Implementing Single-Port Mode .................................................................................................... 2–7
Implementing Simple Dual-Port Mode ......................................................................................... 2–8
Implementing True Dual-Port Mode .......................................................................................... 2–11
Implementing Shift-Register Mode ............................................................................................. 2–14
Implementing ROM Mode ............................................................................................................ 2–15
Implementing FIFO Buffers .......................................................................................................... 2–16
Clock Modes ......................................................................................................................................... 2–16
Independent Clock Mode .............................................................................................................. 2–16
Input/Output Clock Mode ........................................................................................................... 2–18
Read/Write Clock Mode ............................................................................................................... 2–21
Single-Port Mode ............................................................................................................................ 2–23
Designing With TriMatrix Memory .................................................................................................. 2–23
Selecting TriMatrix Memory Blocks ............................................................................................ 2–24
Pipeline & Flow-Through Modes ................................................................................................ 2–24
Power-up Conditions & Memory Initialization ......................................................................... 2–25
Read-During-Write Operation at the Same Address ..................................................................... 2–25
Same-Port Read-During-Write Mode .......................................................................................... 2–25
Mixed-Port Read-During-Write Mode ........................................................................................ 2–26
Conclusion ............................................................................................................................................ 2–27
Chapter 3. External Memory Interfaces in Stratix & Stratix GX Devices
Introduction ............................................................................................................................................ 3–1
External Memory Standards ................................................................................................................ 3–1
DDR SDRAM .................................................................................................................................... 3–1
RLDRAM II ....................................................................................................................................... 3–4
QDR & QDRII SRAM ...................................................................................................................... 3–6
ZBT SRAM ......................................................................................................................................... 3–8
DDR Memory Support Overview ..................................................................................................... 3–10
DDR Memory Interface Pins ......................................................................................................... 3–11
DQS Phase-Shift Circuitry ............................................................................................................ 3–15
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DDR Registers ................................................................................................................................. 3–20
PLL ................................................................................................................................................... 3–27
Conclusion ............................................................................................................................................ 3–27
Section III. I/O Standards
Revision History .................................................................................................................... Section III–1
Chapter 4. Selectable I/O Standards in Stratix & Stratix GX Devices
Introduction ............................................................................................................................................ 4–1
Stratix & Stratix GX I/O Standards .................................................................................................... 4–1
3.3-V Low Voltage Transistor-Transistor Logic (LVTTL) - EIA/JEDEC Standard JESD8-B . 4–2
3.3-V LVCMOS - EIA/JEDEC Standard JESD8-B ........................................................................ 4–3
2.5-V LVTTL Normal Voltage Range - EIA/JEDEC Standard EIA/JESD8-5 .......................... 4–3
2.5-V LVCMOS Normal Voltage Range - EIA/JEDEC Standard EIA/JESD8-5 ..................... 4–3
1.8-V LVTTL Normal Voltage Range - EIA/JEDEC Standard EIA/JESD8-7 .......................... 4–4
1.8-V LVCMOS Normal Voltage Range - EIA/JEDEC Standard EIA/JESD8-7 ..................... 4–4
1.5-V LVCMOS Normal Voltage Range - EIA/JEDEC Standard JESD8-11 ............................ 4–4
1.5-V HSTL Class I & II - EIA/JEDEC Standard EIA/JESD8-6 ................................................. 4–5
1.5-V Differential HSTL - EIA/JEDEC Standard EIA/JESD8-6 ................................................ 4–6
3.3-V PCI Local Bus - PCI Special Interest Group PCI Local Bus Specification Rev. 2.3 ....... 4–6
3.3-V PCI-X 1.0 Local Bus - PCI-SIG PCI-X Local Bus Specification Revision 1.0a ................ 4–7
3.3-V Compact PCI Bus - PCI SIG PCI Local Bus Specification Revision 2.3 .......................... 4–7
3.3-V 1× AGP - Intel Corporation Accelerated Graphics Port Interface Specification 2.0 ..... 4–7
3.3-V 2× AGP - Intel Corporation Accelerated Graphics Port Interface Specification 2.0 ..... 4–8
GTL - EIA/JEDEC Standard EIA/JESD8-3 .................................................................................. 4–8
GTL+ .................................................................................................................................................. 4–8
CTT - EIA/JEDEC Standard JESD8-4 ............................................................................................ 4–9
SSTL-3 Class I & II - EIA/JEDEC Standard JESD8-8 .................................................................. 4–9
SSTL-2 Class I & II - EIA/JEDEC Standard JESD8-9A ............................................................. 4–10
SSTL-18 Class I & II - EIA/JEDEC Preliminary Standard JC42.3 ............................................ 4–11
Differential SSTL-2 - EIA/JEDEC Standard JESD8-9A ............................................................. 4–11
LVDS - ANSI/TIA/EIA Standard ANSI/TIA/EIA-644 .......................................................... 4–12
LVPECL ........................................................................................................................................... 4–13
Pseudo Current Mode Logic (PCML) ......................................................................................... 4–13
HyperTransport Technology - HyperTransport Consortium ................................................. 4–14
High-Speed Interfaces ......................................................................................................................... 4–15
OIF-SPI4.2 ........................................................................................................................................ 4–15
OIF-SFI4.1 ........................................................................................................................................ 4–15
10 Gigabit Ethernet Sixteen Bit Interface (XSBI) - IEEE Draft Standard P802.3ae/D2.0 ...... 4–16
RapidIO Interconnect Specification Revision 1.1 ....................................................................... 4–16
HyperTransport Technology - HyperTransport Consortium ................................................. 4–17
UTOPIA Level 4 – ATM Forum Technical Committee Standard AF-PHY-0144.001 ........... 4–17
Stratix & Stratix GX I/O Banks .......................................................................................................... 4–17
Non-Voltage-Referenced Standards ............................................................................................ 4–24
Voltage-Referenced Standards ..................................................................................................... 4–24
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Mixing Voltage Referenced & Non-Voltage Referenced Standards ....................................... 4–25
Drive Strength ...................................................................................................................................... 4–26
Standard Current Drive Strength ................................................................................................. 4–26
Programmable Current Drive Strength ...................................................................................... 4–27
Hot Socketing ....................................................................................................................................... 4–27
DC Hot Socketing Specification ................................................................................................... 4–28
AC Hot Socketing Specification ................................................................................................... 4–28
I/O Termination .................................................................................................................................. 4–28
Voltage-Referenced I/O Standards ............................................................................................. 4–28
Differential I/O Standards ............................................................................................................ 4–29
Differential Termination (RD) ...................................................................................................... 4–29
Transceiver Termination ............................................................................................................... 4–30
I/O Pad Placement Guidelines .......................................................................................................... 4–30
Differential Pad Placement Guidelines ....................................................................................... 4–30
VREF Pad Placement Guidelines ................................................................................................. 4–31
Output Enable Group Logic Option in Quartus II .................................................................... 4–34
Toggle Rate Logic Option in Quartus II ...................................................................................... 4–35
DC Guidelines ................................................................................................................................. 4–35
Power Source of Various I/O Standards ......................................................................................... 4–38
Quartus II Software Support .............................................................................................................. 4–38
Compiler Settings ........................................................................................................................... 4–38
Device & Pin Options .................................................................................................................... 4–39
Assign Pins ...................................................................................................................................... 4–39
Programmable Drive Strength Settings ...................................................................................... 4–40
I/O Banks in the Floorplan View ................................................................................................. 4–40
Auto Placement & Verification of Selectable I/O Standards ................................................... 4–41
Conclusion ............................................................................................................................................ 4–42
More Information ................................................................................................................................ 4–42
References ............................................................................................................................................. 4–42
Chapter 5. High-Speed Differential I/O Interfaces in Stratix Devices
Introduction ............................................................................................................................................ 5–1
Stratix I/O Banks ................................................................................................................................... 5–1
Stratix Differential I/O Standards ................................................................................................. 5–2
Stratix Differential I/O Pin Location ............................................................................................. 5–5
Principles of SERDES Operation ......................................................................................................... 5–6
Stratix Differential I/O Receiver Operation ................................................................................. 5–7
Stratix Differential I/O Transmitter Operation ........................................................................... 5–9
Transmitter Clock Output ............................................................................................................. 5–10
Divided-Down Transmitter Clock Output ................................................................................. 5–10
Center-Aligned Transmitter Clock Output ................................................................................ 5–11
SDR Transmitter Clock Output .................................................................................................... 5–12
Using SERDES to Implement DDR ................................................................................................... 5–13
Using SERDES to Implement SDR .................................................................................................... 5–14
Differential I/O Interface & Fast PLLs ............................................................................................. 5–16
Clock Input & Fast PLL Output Relationship ............................................................................ 5–18
Fast PLL Specifications .................................................................................................................. 5–20
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High-Speed Phase Adjust ............................................................................................................. 5–21
Counter Circuitry ........................................................................................................................... 5–22
Fast PLL SERDES Channel Support ............................................................................................ 5–23
Advanced Clear & Enable Control .............................................................................................. 5–25
Receiver Data Realignment ................................................................................................................ 5–25
Data Realignment Principles of Operation ................................................................................. 5–25
Generating the TXLOADEN Signal ............................................................................................. 5–27
Realignment Implementation ....................................................................................................... 5–28
Source-Synchronous Timing Budget ................................................................................................ 5–30
Differential Data Orientation ........................................................................................................ 5–30
Differential I/O Bit Position ......................................................................................................... 5–31
Timing Definition ........................................................................................................................... 5–32
Input Timing Waveform ............................................................................................................... 5–39
Output Timing ................................................................................................................................ 5–40
Receiver Skew Margin ................................................................................................................... 5–40
Switching Characteristics .............................................................................................................. 5–42
Timing Analysis .............................................................................................................................. 5–42
SERDES Bypass DDR Differential Signaling ................................................................................... 5–42
SERDES Bypass DDR Differential Interface Review ................................................................. 5–42
SERDES Clock Domains ................................................................................................................ 5–42
SERDES Bypass DDR Differential Signaling Receiver Operation .......................................... 5–43
SERDES Bypass DDR Differential Signaling Transmitter Operation ..................................... 5–44
High-Speed Interface Pin Locations ................................................................................................. 5–45
Differential I/O Termination ............................................................................................................. 5–46
RD Differential Termination .......................................................................................................... 5–46
HyperTransport & LVPECL Differential Termination ............................................................. 5–47
PCML Differential Termination ................................................................................................... 5–47
Differential HSTL Termination .................................................................................................... 5–48
Differential SSTL-2 Termination .................................................................................................. 5–49
Board Design Consideration .............................................................................................................. 5–50
Software Support ................................................................................................................................. 5–51
Differential Pins in Stratix ............................................................................................................. 5–51
Fast PLLs .......................................................................................................................................... 5–52
LVDS Receiver Block ..................................................................................................................... 5–60
LVDS Transmitter Module ........................................................................................................... 5–65
SERDES Bypass Mode ................................................................................................................... 5–70
Summary ............................................................................................................................................... 5–75
Section IV. Digital Signal Processing (DSP)
Revision History .................................................................................................................... Section IV–1
Chapter 6. DSP Blocks in Stratix & Stratix GX Devices
Introduction ............................................................................................................................................ 6–1
DSP Block Overview ............................................................................................................................. 6–2
Architecture ............................................................................................................................................ 6–5
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Multiplier Block ................................................................................................................................ 6–5
Adder/Output Block ....................................................................................................................... 6–9
Routing Structure & Control Signals ........................................................................................... 6–12
Operational Modes .............................................................................................................................. 6–18
Simple Multiplier Mode ................................................................................................................ 6–18
Multiply Accumulator Mode ........................................................................................................ 6–22
Two-Multiplier Adder Mode ........................................................................................................ 6–23
Four-Multiplier Adder Mode ....................................................................................................... 6–24
Software Support ................................................................................................................................. 6–28
Conclusion ............................................................................................................................................ 6–28
Chapter 7. Implementing High Performance DSP Functions
in Stratix & Stratix GX Devices
Introduction ............................................................................................................................................ 7–1
Stratix & Stratix GX DSP Block Overview ......................................................................................... 7–1
TriMatrix Memory Overview .............................................................................................................. 7–4
DSP Function Overview ....................................................................................................................... 7–5
Finite Impulse Response (FIR) Filters ................................................................................................. 7–5
FIR Filter Background ...................................................................................................................... 7–6
Basic FIR Filter .................................................................................................................................. 7–7
Time-Domain Multiplexed FIR Filters ........................................................................................ 7–13
Polyphase FIR Interpolation Filters ............................................................................................. 7–17
Polyphase FIR Decimation Filters ................................................................................................ 7–24
Complex FIR Filter ......................................................................................................................... 7–31
Infinite Impulse Response (IIR) Filters ............................................................................................. 7–34
IIR Filter Background .................................................................................................................... 7–34
Basic IIR Filters ............................................................................................................................... 7–36
Butterworth IIR Filters ................................................................................................................... 7–39
Matrix Manipulation ........................................................................................................................... 7–45
Background on Matrix Manipulation .......................................................................................... 7–45
Two-Dimensional Filtering & Video Imaging ........................................................................... 7–46
Discrete Cosine Transform (DCT) ..................................................................................................... 7–52
DCT Background ............................................................................................................................ 7–52
2-D DCT Algorithm ....................................................................................................................... 7–53
Arithmetic Functions ........................................................................................................................... 7–59
Background ..................................................................................................................................... 7–59
Arithmetic Function Implementation ......................................................................................... 7–60
Arithmetic Function Implementation Results ............................................................................ 7–62
Arithmetic Function Design Example ......................................................................................... 7–62
Conclusion ............................................................................................................................................ 7–62
References ............................................................................................................................................. 7–63
Section V. IP & Design Considerations
Revision History ..................................................................................................................... Section V–1
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Chapter 8. Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Introduction ............................................................................................................................................ 8–1
Related Links ..................................................................................................................................... 8–1
10-Gigabit Ethernet ................................................................................................................................ 8–1
Interfaces ................................................................................................................................................. 8–5
XSBI .................................................................................................................................................... 8–5
XGMII ............................................................................................................................................... 8–13
XAUI ................................................................................................................................................. 8–19
I/O Characteristics for XSBI, XGMII & XAUI ................................................................................. 8–21
Software Implementation .............................................................................................................. 8–22
AC/DC Specifications ................................................................................................................... 8–22
10-Gigabit Ethernet MAC Core .................................................................................................... 8–24
Conclusion ....................................................................................................................................... 8–25
Chapter 9. Implementing SFI-4 in Stratix & Stratix GX Devices
Introduction ............................................................................................................................................ 9–1
System Topology .............................................................................................................................. 9–3
Interface Implementation in Stratix & Stratix GX Devices ......................................................... 9–5
AC Timing Specifications .............................................................................................................. 9–10
Electrical Specifications ................................................................................................................. 9–12
Software Implementation .............................................................................................................. 9–13
Conclusion ....................................................................................................................................... 9–13
Chapter 10. Transitioning APEX Designs to Stratix & Stratix GX Devices
Introduction .......................................................................................................................................... 10–1
General Architecture ........................................................................................................................... 10–1
Logic Elements ................................................................................................................................ 10–2
MultiTrack Interconnect ................................................................................................................ 10–3
DirectDrive Technology ................................................................................................................ 10–4
Architectural Element Names ...................................................................................................... 10–5
TriMatrix Memory ............................................................................................................................... 10–8
Same-Port Read-During-Write Mode ........................................................................................ 10–10
Mixed-Port Read-During-Write Mode ...................................................................................... 10–11
Memory Megafunctions .............................................................................................................. 10–12
FIFO Conditions ........................................................................................................................... 10–13
Design Migration Mode in Quartus II Software ...................................................................... 10–13
DSP Block ............................................................................................................................................ 10–16
DSP Block Megafunctions ........................................................................................................... 10–16
PLLs & Clock Networks ................................................................................................................... 10–18
Clock Networks ............................................................................................................................ 10–18
PLLs ................................................................................................................................................ 10–19
I/O Structure ...................................................................................................................................... 10–25
External RAM Interfacing ........................................................................................................... 10–25
I/O Standard Support ................................................................................................................. 10–26
High-Speed Differential I/O Standards .................................................................................... 10–26
altlvds Megafunction ................................................................................................................... 10–29
Configuration ..................................................................................................................................... 10–30
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Configuration Speed & Schemes ................................................................................................
Remote Update Configuration ...................................................................................................
JTAG Instruction Support ...........................................................................................................
Conclusion ..........................................................................................................................................
10–30
10–31
10–31
10–32
Section VI. System Configuration & Upgrades
Revision History .................................................................................................................... Section VI–2
Chapter 11. Configuring Stratix & Stratix GX Devices
Introduction .......................................................................................................................................... 11–1
Device Configuration Overview ....................................................................................................... 11–2
MSEL[2..0] Pins ............................................................................................................................... 11–3
VCCSEL Pins ...................................................................................................................................... 11–3
PORSEL Pins ................................................................................................................................... 11–5
nIO_PULLUP Pins ......................................................................................................................... 11–5
TDO & nCEO Pins .......................................................................................................................... 11–6
Configuration File Size ....................................................................................................................... 11–6
Altera Configuration Devices ............................................................................................................ 11–7
Configuration Schemes ....................................................................................................................... 11–7
PS Configuration ............................................................................................................................ 11–7
FPP Configuration ........................................................................................................................ 11–21
PPA Configuration ....................................................................................................................... 11–30
JTAG Programming & Configuration ....................................................................................... 11–36
JTAG Programming & Configuration of Multiple Devices ................................................... 11–39
Configuration with JRunner Software Driver .......................................................................... 11–41
Jam STAPL Programming & Test Language ............................................................................ 11–42
Configuring Using the MicroBlaster Driver .................................................................................. 11–51
Device Configuration Pins ............................................................................................................... 11–51
Chapter 12. Remote System Configuration with Stratix & Stratix GX Devices
Introduction .......................................................................................................................................... 12–1
Remote Configuration Operation ...................................................................................................... 12–1
Remote System Configuration Modes ........................................................................................ 12–3
Remote System Configuration Components .............................................................................. 12–5
Quartus II Software Support ............................................................................................................ 12–12
altremote_update Megafunction ................................................................................................ 12–14
Remote Update WYSIWYG ATOM ........................................................................................... 12–17
Using Enhanced Configuration Devices ........................................................................................ 12–19
Local Update Programming File Generation ........................................................................... 12–21
Remote Update Programming File Generation ....................................................................... 12–32
Combining MAX Devices & Flash Memory .................................................................................. 12–42
Using an External Processor ............................................................................................................ 12–43
Conclusion .......................................................................................................................................... 12–44
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Section VII. PCB Layout Guidelines
Revision History .................................................................................................................. Section VII–1
Chapter 13. Package Information for Stratix Devices
Introduction .......................................................................................................................................... 13–1
Device & Package Cross Reference ................................................................................................... 13–1
Thermal Resistance .............................................................................................................................. 13–2
Package Outlines ................................................................................................................................. 13–3
484-Pin FineLine BGA - Flip Chip ............................................................................................... 13–4
672-Pin FineLine BGA - Flip Chip ............................................................................................... 13–6
780-Pin FineLine BGA - Flip Chip ............................................................................................... 13–8
956-Pin Ball Grid Array (BGA) - Flip Chip ............................................................................... 13–10
1,020-Pin FineLine BGA - Flip Chip .......................................................................................... 13–12
1,508-Pin FineLine BGA - Flip Chip .......................................................................................... 13–14
Chapter 14. Designing with 1.5-V Devices
Introduction .......................................................................................................................................... 14–1
Power Sequencing & Hot Socketing ................................................................................................. 14–1
Using MultiVolt I/O Pins ................................................................................................................... 14–2
Voltage Regulators .............................................................................................................................. 14–3
Linear Voltage Regulators ............................................................................................................. 14–5
Switching Voltage Regulators ...................................................................................................... 14–7
Maximum Output Current ........................................................................................................... 14–8
Selecting Voltage Regulators ........................................................................................................ 14–9
Voltage Divider Network ............................................................................................................ 14–10
1.5-V Regulator Circuits .............................................................................................................. 14–10
1.5-V Regulator Application Examples .......................................................................................... 14–19
Synchronous Switching Regulator Example ............................................................................ 14–20
Board Layout ...................................................................................................................................... 14–21
Split-Plane Method ....................................................................................................................... 14–23
Conclusion .......................................................................................................................................... 14–23
References ........................................................................................................................................... 14–24
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Chapter Revision Dates
The chapters in this book, Stratix Device Handbook, Volume 2, were revised on the following dates.
Where chapters or groups of chapters are available separately, part numbers are listed.
Chapter 1. General-Purpose PLLs in Stratix & Stratix GX Devices
Revised:
July 2005
Part number: S52001-3.2
Chapter 2. TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Revised:
July 2005
Part number: S52003-3.3
Chapter 3. External Memory Interfaces in Stratix & Stratix GX Devices
Revised:
June 2006
Part number: SII52003-3.3
Chapter 4.
Selectable I/O Standards in Stratix & Stratix GX Devices
Revised:
June 2006
Part number: S52004-3.4
Chapter 5. High-Speed Differential I/O Interfaces in Stratix Devices
Revised:
July 2005
Part number: S52005-3.2
Chapter 6. DSP Blocks in Stratix & Stratix GX Devices
Revised:
July 2005
Part number: S52006-2.2
Chapter 7. Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Revised:
September 2004
Part number: S52007-1.1
Chapter 8. Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Revised:
July 2005
Part number: S52010-2.0
Chapter 9. Implementing SFI-4 in Stratix & Stratix GX Devices
Revised:
July 2005
Part number: S52011-2.0
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Chapter Revision Dates
Stratix Device Handbook, Volume 2
Chapter 10. Transitioning APEX Designs to Stratix & Stratix GX Devices
Revised:
July 2005
Part number: S52012-3.0
Chapter 11. Configuring Stratix & Stratix GX Devices
Revised:
July 2005
Part number: S52013-3.2
Chapter 12. Remote System Configuration with Stratix & Stratix GX Devices
Revised:
September 2004
Part number: S52015-3.1
Chapter 13. Package Information for Stratix Devices
Revised:
July 2005
Part number: S53008-3.0
Chapter 14. Designing with 1.5-V Devices
Revised:
January 2005
Part number: C51012-1.1
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Altera Corporation
About This Handbook
This handbook provides comprehensive information about the Altera®
Stratix® family of devices.
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Typographic Conventions
Typographic
Conventions
Visual Cue
Stratix Device Handbook, Volume 2
This document uses the typographic conventions shown below.
Meaning
Bold Type with Initial
Capital Letters
Command names, dialog box titles, checkbox options, and dialog box options are
shown in bold, initial capital letters. Example: Save As dialog box.
bold type
External timing parameters, directory names, project names, disk drive names,
filenames, filename extensions, and software utility names are shown in bold
type. Examples: fMAX, \qdesigns directory, d: drive, chiptrip.gdf file.
Italic Type with Initial Capital
Letters
Document titles are shown in italic type with initial capital letters. Example: AN 75:
High-Speed Board Designs.
Italic type
Internal timing parameters and variables are shown in italic type.
Examples: tPIA, n + 1.
Variable names are enclosed in angle brackets (< >) and shown in italic type.
Example: <file name>, <project name>.pof file.
Initial Capital Letters
Keyboard keys and menu names are shown with initial capital letters. Examples:
Delete key, the Options menu.
“Subheading Title”
References to sections within a document and titles of on-line help topics are
shown in quotation marks. Example: “Typographic Conventions.”
Courier type
Signal and port names are shown in lowercase Courier type. Examples: data1,
tdi, input. Active-low signals are denoted by suffix n, e.g., resetn.
Anything that must be typed exactly as it appears is shown in Courier type. For
example: c:\qdesigns\tutorial\chiptrip.gdf. Also, sections of an
actual file, such as a Report File, references to parts of files (e.g., the AHDL
keyword SUBDESIGN), as well as logic function names (e.g., TRI) are shown in
Courier.
1., 2., 3., and
a., b., c., etc.
Numbered steps are used in a list of items when the sequence of the items is
important, such as the steps listed in a procedure.
■
Bullets are used in a list of items when the sequence of the items is not important.
●
•
v
The checkmark indicates a procedure that consists of one step only.
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The hand points to information that requires special attention.
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The angled arrow indicates you should press the Enter key.
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The feet direct you to more information on a particular topic.
xvi
Altera Corporation
Section I. Clock
Management
This section provides information on the different types of phase-lock
loops (PLLs). The feature-rich, enhanced PLLs assist you in managing
clocks internally and also have the ability to drive off-chip to control
system-level clock networks. The fast PLLs offer general-purpose clock
management with multiplication and phase shifting as well as
high-speed outputs to manage the high-speed differential I/O interfaces.
This chapter contains detailed information on the features, the
interconnections to the core and off-chip, and the specifications for both
types of PLLs.
This section contains the following:
■
Revision History
Chapter
Date/Version
1
July 2005, v3.2
Chapter 1, General-Purpose PLLs in Stratix & Stratix GX Devices
The table below shows the revision history for Chapter 1.
Changes Made
●
●
●
●
●
●
September 2004, v3.1
●
●
●
April 2004, v3.0
●
●
●
●
●
●
●
●
●
●
Altera Corporation
Removed information regarding delay shift (time delay elements).
Updated Table 1–8.
Updated “Clock Switchover” section.
Updated Figure 1–22.
Updated “Control Signals” section.
Updated Table 1–16.
Updated Note 1 in Table 1–17 on page 1–32.
Updated Note 1 in Table 1–21 on page 1–48.
Updated Table 1–12 on page 1–34.
Changed PCI-X to PCI-X 1.0 throughout volume.
Note 3 added to columns 11 and 12 in Table 1–1.
Deleted “Stratix GX Clock Input Sources for Enhanced and Fast PLLs”
table.
Deleted “Stratix GX Global and Regional Clock Output Line Sharing for
Enhanced and Fast PLLS” table.
Deleted “Stratix GX CLK and FPLLCLK Input Pin Connections to Global
& Regional Clock Networks” table.
Changed CLK checkmarks in Table 1–14.
Updated notes to Table 1–3. and Figure 1–3.
Added Table 1–7.
Clock Switchover section has been moved to AN 313.
Changed RCLK values in Figures 1–20 and 1–22.
Section I–1
Clock Management
Stratix Device Handbook, Volume 2
Chapter
Date/Version
Changes Made
1
November 2003, v2.2
●
Updated the “Lock Detect” section.
October 2003, v2.1
●
Updated the “VCCG & GNDG” section.
Updated Figure 1–14.
●
July 2003, v2.0
●
●
●
●
●
●
●
●
●
Section I–2
Updated clock multiplication and division, spread spectrum, and Notes 1
and 8 in Table 1-3.
Updated inclk[1..0] port name in Table 1-4.
Updated ranges for EPLL post-scale and pre-scale dividers on page 1-9
Added 1.8V HSTL support for EPLL in Table 1-6 and 1-13.
New requirement to assert are set signal each PLL when it has to reacquire lock on either a new clock after loss of lock (page 1-16)
Corrected input port extswitch to clkswitch throughout this
chapter.
Updated clkloss description in Table 1-9.
Updated text on jitter for spread spectrum on page 1-38.
Removed PLL specifications. See Chapter 4 of Volume 1.
Altera Corporation
1. General-Purpose PLLs in
Stratix & Stratix GX Devices
S52001-3.2
Introduction
Stratix® and Stratix GX devices have highly versatile phase-locked loops
(PLLs) that provide robust clock management and synthesis for on-chip
clock management, external system clock management, and high-speed
I/O interfaces. There are two types of PLLs in each Stratix and Stratix GX
device: enhanced PLLs and fast PLLs. Each device has up to four
enhanced PLLs, which are feature-rich, general-purpose PLLs supporting
advanced capabilities such as external feedback, clock switchover, phase
and delay control, PLL reconfiguration, spread spectrum clocking, and
programmable bandwidth. There are also up to eight fast PLLs per
device, which offer general-purpose clock management with
multiplication and phase shifting as well as high-speed outputs to
manage the high-speed differential I/O interfaces.
The Altera® Quartus® II software enables the PLLs and their features
without requiring any external devices.
Tables 1–1 and 1–2 show PLL availability for Stratix and Stratix GX
devices, respectively.
Table 1–1. Stratix Device PLL Availability
Fast PLLs
Enhanced PLLs
Device
1
2
3
4
EP1S10
v
v
v
EP1S20
v
v
EP1S25
v
EP1S30
7
8
9
10
5(1)
6(1)
11(2)
12(2)
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v (3)
v (3)
v (3)
v (3)
v
v
EP1S40
v
v
v
v
v (3)
v (3)
v (3)
v (3)
v
v
v (3)
v (3)
EP1S60
v
v
v
v
v
v
v
v
v
v
v
v
EP1S80
v
v
v
v
v
v
v
v
v
v
v
v
Notes to Table 1–1:
(1)
(2)
PLLs 5 and 6 each have eight single-ended outputs or four differential outputs.
PLLs 11 and 12 each have one single-ended output.
(3)
EP1S30 and EP1S40 devices do not support these PLLs in the 780-pin FineLine BGA® package.
Altera Corporation
July 2005
1–1
Introduction
Table 1–2. Stratix GX Device PLL Availability
Fast PLLs
Enhanced PLLs
Device
1
2
EP1S10C
v
EP1S10D
5
6
v
v
v
v
v
v
v
EP1S25C
v
v
v
v
EP1S25D
v
v
v
v
EP1S25F
v
v
v
v
EP1S40D
v
v
v
v
v
EP1S40G
v
v
v
v
v
1–2
Stratix Device Handbook, Volume 2
7
8
11
12
v
v
v
v
v
v
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Table 1–3 shows the enhanced and fast PLL features in Stratix and
Stratix GX devices.
Table 1–3. Stratix & Stratix GX PLL Features
Feature
Enhanced PLL
Fast PLL
Clock multiplication and division
m/(n × post-scale counter) (1)
m/(post-scale counter) (2)
Down to 156.25-ps increments (3), (4)
Down to 125-ps increments (3), (4)
Phase shift
Clock switchover
v
PLL reconfiguration
v
Programmable bandwidth
v
Spread spectrum clocking
v
Programmable duty cycle
v
v
Number of internal clock outputs
6
3 (5)
Number of external clock outputs
Four differential/eight singled-ended
or one single-ended (6)
(7)
Number of feedback clock inputs
2 (8)
Notes to Table 1–3:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
For enhanced PLLs, m, n, range from 1 to 512 and post-scale counters g, l, e range from 1 to 1024 with 50% duty
cycle. With a non-50% duty cycle the post-scale counters g, l, e range from 1 to 512.
For fast PLLs, m, n, and post-scale counters range from 1 to 32.
The smallest phase shift is determined by the voltage controlled oscillator (VCO) period divided by 8.
For degree increments, Stratix and Stratix GX devices can shift all output frequencies in increments of at least 45° .
Smaller degree increments are possible depending on the frequency and divide parameters.
PLLs 7, 8, 9, and 10 have two output ports per PLL. PLLs 1, 2, 3, and 4 have three output ports per PLL. On Stratix
GX devices, PLLs 3, 4, 9, and 10 are not available for general-purpose use.
Every Stratix and Stratix GX device has two enhanced PLLs (PLLs 5 and 6) with either eight single-ended outputs
or four differential outputs each. Two additional enhanced PLLs (PLLs 11 and 12) in EP1S80, EP1S60, EP1S40 (PLL
11 and 12 not supported for F780 package), and EP1SGX40 devices each have one single-ended output.
Fast PLLs can drive to any I/O pin as an external clock. For high-speed differential I/O pins, the device uses a data
channel to generate txclkout.
Every Stratix and Stratix GX device has two enhanced PLLs with one single-ended or differential external feedback
input per PLL.
Altera Corporation
July 2005
1–3
Stratix Device Handbook, Volume 2
Introduction
Figure 1–1 shows a top-level diagram of the Stratix device and PLL
floorplan. Figure 1–2 shows a top-level diagram of the Stratix GX device
and PLL floorplan. See “Clocking” on page 1–39 for more detail on PLL
connections to global and regional clocks.
Figure 1–1. Stratix PLL Locations
CLK12-15
5
11
FPLL7CLK
7
10
FPLL10CLK
CLK0-3
1
2
4
3
CLK8-11
8
9
FPLL9CLK
PLLs
FPLL8CLK
6
12
CLK4-7
1–4
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Figure 1–2. Stratix GX PLL Locations
CLK12-15
5
LVDSCLK0
11
7
HSSI
CLK0-3
1
2
PLLs
LVDSCLK1
HSSI
8
6
12
CLK4-7
Enhanced PLLs
Altera Corporation
July 2005
Stratix and Stratix GX devices contain up to four enhanced PLLs with
advanced clock management features. Figure 1–3 shows a diagram of the
enhanced PLL.
1–5
Stratix Device Handbook, Volume 2
Enhanced PLLs
Figure 1–3. Stratix & Stratix GX Enhanced PLL
Programmable
Time Delay on
Each PLL Port
Post-Scale
Counters
VCO Phase Selection
Selectable at Each
PLL Output Port
From Adjacent PLL (4)
÷l0
Δt
Regional
Clocks
Clock
Switch-Over
Circuitry
÷l1
Δt
Spread
Spectrum
Phase Frequency
Detector (PFD)
INCLK0
4
Δtn
÷n
Charge
Pump
8
Loop
Filter
VCO
INCLK1
(1)
FBIN
Δtm
÷m
÷g0
Δt
÷g1
Δt
÷g2
Δt
÷g3
Δt
÷e0
Δt
÷e1
Δt
÷e2
Δt
÷e3
Δt
Global
Clocks
I/O Buffers (2)
to I/O or general
routing
Lock Detect
& Filter
VCO Phase Selection
Affecting All Outputs
4
I/O Buffers (3)
Notes to Figure 1–3:
(1)
(2)
(3)
(4)
External feedback is available in PLLs 5 and 6.
This single-ended external output is available from the g0 counter for PLLs 11 and 12.
These four counters and external outputs are available in PLLs 5 and 6.
This connection is only available on EP1SGX40 Stratix GX devices and EP1S40 and larger Stratix devices. For
example, PLLs 5 and 11 are adjacent and PLLs 6 and 12 are adjacent. The EP1S40 device in the F780 package does
not support PLLs 11 and 12.
1–6
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Figure 1–4 shows all the possible ports of the enhanced PLLs.
Figure 1–4. Enhanced PLL Signals
(1)
pllenable
(2)
inclk0
(2)
inclk1
areset
clkswitch
scanclk
Physical Pin
clk[5..0]
Signal Driven by Internal Logic
Signal Driven to Internal Logic
Internal Clock Signal
locked
clkloss
clkbad[1..0]
active_clock
scandata
scanaclr
clkena[5..0]
Only PLLs
11 and 12
extclk4
scandataout
pfdena
(2)
fbin
Only PLLs
5 and 6
pll_out0p
pll_out0n
extclkena[3..0]
pll_out1p
pll_out1n
pll_out2p
(3)
pll_out2n
(3)
pll_out3p
(3)
pll_out3n
(3)
Notes to Figure 1–4:
(1)
(2)
(3)
This input pin is shared by all enhanced and fast PLLs.
These are either single-ended or differential pins.
EP1S10, EP1S20, and EP1S25 devices in 672-pin ball grid array (BGA) and 484- and 672-pin FineLine BGA packages
only have two pairs of external clocks (i.e., pll_out0p, pll_out0n, pll_out1p, and pll_out1n).
Altera Corporation
July 2005
1–7
Stratix Device Handbook, Volume 2
Enhanced PLLs
Tables 1–4 and 1–5 describe all the enhanced PLL ports.
Table 1–4. Enhanced PLL Input Signals
Port
Description
Source
Destination
inclk[1..0]
Primary and secondary reference clock inputs to
PLL
Pin
×n counter
fbin
External feedback input to the PLL (PLLs 5 and 6
only)
Pin
Phase frequency
detector (PFD)
pllena
Enable pin for enabling or disabling all or a set of
PLLs⎯active high
Pin
General PLL
control signal
clkswitch
Switchover signal used to initiate external clock
switchover control⎯this signal switches the clock
on the rising edge of clkswitch
Logic array
PLL switchover
circuit
areset
Signal used to reset the PLL which resynchronizes all the counter outputs⎯active high
Logic array
General PLL
control signal
clkena[5..0]
Enable clock driving regional or global
clock⎯active high
Logic array
Clock output
extclkena[3..0]
Enable clock driving external clock (PLLs 5 and 6
only)⎯active high
Logic array
Clock output
pfdena
Enables the outputs from the phase frequency
detector⎯active high
Logic array
PFD
scanclk
Serial clock signal for the real-time PLL control
feature
Logic array
Reconfiguration
circuit
scandata
Serial input data stream for the real-time PLL
control feature
Logic array
Reconfiguration
circuit
scanaclr
Serial shift register reset clearing all registers in
the serial shift chain⎯active high
Logic array
Reconfiguration
circuit
1–8
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Table 1–5. Enhanced PLL Output Signals
Port
Description
Source
Destination
clk[5..0]
PLL outputs driving regional or global clock
PLL counter Internal Clock
pll_out[3..0]p/n
pll_out[3..0] are PLL outputs driving the four PLL counter Pin(s)
differential or eight single-ended external clock
output pins for PLLs 5 or 6. p or n are the positive
(p) and negative (n) pins for differential pins.
extclk4
PLL output driving external clock output pin from
PLLs 11 and 12
clkloss
Signal indicating the switchover circuit detected a PLL
switchover condition
switchover
circuit
Logic array
clkbad[1..0]
Signals indicating which reference clock is no
longer toggling. clkbad1 indicates inclk1
status, clkbad0 indicates inclk0 status
PLL
switchover
circuit
Logic array
locked
Lock output from lock detect circuit⎯active high
PLL lock
detect
Logic array
activeclock
Signal to indicate which clock (1 = inclk0 or
0 = inclk1) is driving the PLL.
PLL clock
multiplexer
Logic array
scandataout
Output of the last shift register in the scan chain
PLL scan
chain
Logic array
PLL g0
counter
Pin
Clock Multiplication & Division
Each Stratix and Stratix GX device enhanced PLL provides clock
synthesis for PLL output ports using m/(n × post-scale counter) scaling
factors. The input clock is divided by a pre-scale counter, n, and is then
multiplied by the m feedback factor. The control loop drives the VCO to
match fIN × (m/n). Each output port has a unique post-scale counter that
divides down the high-frequency VCO.
For multiple PLL outputs with different frequencies, the VCO is set to the
least common multiple of the output frequencies that meets its frequency
specifications. Then, the post-scale counters scale down the output
frequency for each output port. For example, if output frequencies
required from one PLL are 33 and 66 MHz, then the Quartus II software
sets the VCO to 330 MHz (the least common multiple of 33 and 66 MHz
within the VCO range).
There is one pre-scale counter, n, and one multiply counter, m, per PLL,
with a range of 1 to 512 on each. There are two post-scale counters (l) for
regional clock output ports, four counters (g) for global clock output
ports, and up to four counters (e) for external clock outputs, all ranging
from 1 to 1024 with a 50% duty cycle setting. The post-scale counters
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Enhanced PLLs
range from 1 to 512 with any non-50% duty cycle setting. The Quartus II
software automatically chooses the appropriate scaling factors according
to the input frequency, multiplication, and division values entered into
the altpll MegaWizard Plug-In Manager.
External Clock Outputs
Enhanced PLLs 5 and 6 each support up to eight single-ended clock
outputs (or four differential pairs). See Figure 1–5.
1–10
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Figure 1–5. External Clock Outputs for PLLs 5 & 6
From IOE (1), (2)
pll_out0p (3), (4)
(3)
e0 Counter
From IOE (1)
From IOE (1)
pll_out0n (3), (4)
pll_out1p (3), (4)
e1 Counter
4
From IOE (1)
From IOE (1)
pll_out1n (3), (4)
pll_out2p (3), (4)
e2 Counter
pll_out2n (3), (4)
From IOE (1)
From IOE (1)
pll_out3p (3), (4)
e3 Counter
From IOE (1)
pll_out3n (3), (4)
Notes to Figure 1–5:
(1)
(2)
(3)
(4)
LE: logic element.
The design can use each external clock output pin as a general-purpose output pin from the logic array. These pins
are multiplexed with IOE outputs.
Two single-ended outputs are possible per output counter⎯either two outputs of the same frequency and phase or
one shifted 180° .
EP1S10, EP1S20, and EP1S25 devices in 672-pin ball grid array (BGA) and 484- and 672-pin FineLine BGA packages
only have two pairs of external clocks (i.e., pll_out0p, pll_out0n, pll_out1p, and pll_out1n).
Any of the four external output counters can drive the single-ended or
differential clock outputs for PLLs 5 and 6. This means one counter or
frequency can drive all output pins available from PLL 5 or PLL 6. Each
Altera Corporation
July 2005
1–11
Stratix Device Handbook, Volume 2
Enhanced PLLs
pair of output pins (four pins total) has dedicated VCC and GND pins to
reduce the output clock’s overall jitter by providing improved isolation
from switching I/O pins.
For PLLs 5 and 6, each pin of a single-ended output pair can either be in
phase or 180° out of phase. The Quartus II software transfers the NOT
gate in the design into the IOE to implement 180° phase with respect to
the other pin in the pair. The clock output pin pairs support the same I/O
standards as standard output pins (in the top and bottom banks) as well
as LVDS, LVPECL, PCML, HyperTransportTM technology, differential
HSTL, and differential SSTL. Table 1–6 shows which I/O standards the
enhanced PLL clock pins support. When in single-ended or differential
mode, one power pin supports two differential or four single-ended pins.
Both outputs use the same standards in single-ended mode to maintain
performance. You can also use the external clock output pins as user
output pins if external enhanced PLL clocking is not needed.
The enhanced PLL can also drive out to any regular I/O pin through the
global or regional clock network. The jitter on the output clock is not
guaranteed for this case.
Table 1–6. I/O Standards Supported for Enhanced PLL Pins (Part 1 of 2)
Input
Output
I/O Standard
INCLK
FBIN
PLLENABLE
EXTCLK
LVTTL
v
v
v
v
LVCMOS
v
v
v
v
2.5 V
v
v
v
1.8 V
v
v
v
1.5 V
v
v
v
3.3-V PCI
v
v
v
3.3-V PCI-X 1.0
v
v
v
LVPECL
v
v
v
PCML
v
v
v
LVDS
v
v
v
HyperTransport technology
v
v
v
Differential HSTL
v
v
v
Differential SSTL
3.3-V GTL
1–12
Stratix Device Handbook, Volume 2
v
v
v
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Table 1–6. I/O Standards Supported for Enhanced PLL Pins (Part 2 of 2)
Input
Output
I/O Standard
INCLK
FBIN
PLLENABLE
EXTCLK
3.3-V GTL+
v
v
v
1.5-V HSTL Class I
v
v
v
1.5-V HSTL Class II
v
v
v
1.8-V HSTL Class I
v
v
v
1.8-V HSTL Class II
v
v
v
SSTL-18 Class I
v
v
v
SSTL-18 Class II
v
v
v
SSTL-2 Class I
v
v
v
SSTL-2 Class II
v
v
v
SSTL-3 Class I
v
v
v
SSTL-3 Class II
v
v
v
AGP (1× and 2×)
v
v
v
CTT
v
v
v
Enhanced PLLs 11 and 12 support one single-ended output each (see
Figure 1–6). These outputs do not have their own VCC and GND signals.
Therefore, to minimize jitter, do not place switching I/O pins next to this
output pin.
Figure 1–6. External Clock Outputs for Enhanced PLLs 11 & 12
g0
Counter
CLK13n, I/O, PLL11_OUT
or CLK6n, I/O, PLL12_OUT (1)
From Internal
Logic or IOE
Note to Figure 1–6:
(1)
For PLL11, this pin is CLK13n; for PLL 12 this pin is CLK6n.
Altera Corporation
July 2005
1–13
Stratix Device Handbook, Volume 2
Enhanced PLLs
Stratix and Stratix GX devices can drive any enhanced PLL driven
through the global clock or regional clock network to any general I/O pin
as an external output clock. The jitter on the output clock is not
guaranteed for these cases.
Clock Feedback
The following three feedback modes in Stratix and Stratix GX device
enhanced PLLs allow multiplication and/or phase shifting:
■
■
■
■
Zero delay buffer: The external clock output pin is phase-aligned
with the clock input pin for zero delay. Altera recommends using the
same I/O standard on the input clock and the output clocks for
optimum performance.
External feedback: The external feedback input pin, FBIN, is phasealigned with the clock input, CLK, pin. Aligning these clocks allows
you to remove clock delay and skew between devices. This mode is
only possible for PLLs 5 and 6. PLLs 5 and 6 each support feedback
for one of the dedicated external outputs, either one single-ended or
one differential pair. In this mode, one encounter feeds back to the
PLL FBIN input, becoming part of the feedback loop.
Normal mode: If an internal clock is used in this mode, it is phasealigned to the input clock pin. The external clock output pin has a
phase delay relative to the clock input pin if connected in this mode.
No compensation: In this mode, the PLL does not compensate for
any clock networks or external clock outputs.
Table 1–7 shows which modes are supported by which PLL type.
Table 1–7. Clock Feedback Mode Availability
Mode Available in
Clock Feedback Mode
Enhanced PLLs
Fast PLLs
Yes
Yes
Normal Mode
Yes
Yes
Zero delay buffer mode
Yes
No
External feedback mode
Yes
No
No compensation mode
Phase Shifting
Stratix and Stratix GX device enhanced PLLs provide advanced
programmable phase shifting. You set these parameters in the Quartus II
software.
1–14
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Phase Delay
The Quartus II software automatically sets the phase taps and counter
settings according to the phase shift entry. You enter a desired phase shift
and the Quartus II software automatically sets the closest setting
achievable. This type of phase shift is not reconfigurable during system
operation. For phase shifting, enter a phase shift (in degrees or time units)
for each PLL clock output port or for all outputs together in one shift.
You can select phase-shifting values in time units with a resolution of
156.25 to 416.66 ps. This resolution is a function of frequency input and
the multiplication and division factors (that is, it is a function of the VCO
period), with the finest step being equal to an eighth (× 0.125) of the VCO
period. Each clock output counter can choose a different phase of the
VCO period from up to eight taps for individual fine-step selection. Also,
each clock output counter can use a unique initial count setting to achieve
individual coarse-shift selection in steps of one VCO period. The
combination of coarse and fine shifts allows phase shifting for the entire
input clock period.
The equation to determine the precision of the phase shifting in degrees
is: 45° ÷ post-scale counter value. Therefore, the maximum step size is
45° , and smaller steps are possible depending on the multiplication and
division ratio necessary on the output counter port.
This type of phase shift provides the highest precision since it is the least
sensitive to process, supply, and temperature variation.
Lock Detect
The lock output indicates that there is a stable clock output signal in
phase with the reference clock. Without any additional circuitry, the lock
signal may toggle as the PLL begins tracking the reference clock. You may
need to gate the lock signal for use as a system control. The lock signal
from the locked port can drive the logic array or an output pin.
Whenever the PLL loses lock for any reason (be it excessive inclk jitter,
clock switchover, PLL reconfiguration, power supply noise, etc.), the PLL
must be reset with the areset signal to guarantee correct phase
relationship between the PLL output clocks. If the phase relationship
between the input clock versus output clock, and between different
output clocks from the PLL is not important in your design, the PLL need
not be reset.
f
Altera Corporation
July 2005
See the Stratix FPGA Errata Sheet for more information on implementing
the gated lock signal in your design.
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Enhanced PLLs
Programmable Duty Cycle
The programmable duty cycle allows enhanced PLLs to generate clock
outputs with a variable duty cycle. This feature is supported on each
enhanced PLL post-scale counter (g0..g3, l0..l3, e0..e3). The duty cycle
setting is achieved by a low and high time count setting for the post-scale
counters. The Quartus II software uses the frequency input and the
required multiply or divide rate to determine the duty cycle choices. The
precision of the duty cycle is determined by the post-scale counter value
chosen on an output. The precision is defined by 50% divided by the postscale counter value. The closest value to 100% is not achievable for a given
counter value. For example, if the g0 counter is 10, then steps of 5% are
possible for duty cycle choices between 5 to 90%.
If the device uses external feedback, you must set the duty cycle for the
counter driving off the device to 50%.
General Advanced Clear & Enable Control
There are several control signals for clearing and enabling PLLs and PLL
outputs. You can use these signals to control PLL resynchronization and
gate PLL output clocks for low-power applications.
The pllenable pin is a dedicated pin that enables/disables PLLs. When
the pllenable pin is low, the clock output ports are driven by GND and
all the PLLs go out of lock. When the pllenable pin goes high again, the
PLLs relock and resynchronize to the input clocks. You can choose which
PLLs are controlled by the pllenable signal by connecting the
pllenable input port of the altpll megafunction to the common
pllenable input pin.
The areset signals are reset/resynchronization inputs for each PLL. The
areset signal should be asserted every time the PLL loses lock to
guarantee correct phase relationship between the PLL output clocks.
Users should include the areset signal in designs if any of the following
conditions are true:
■
■
PLL reconfiguration or clock switchover enables in the design
Phase relationships between output clocks need to be maintained
after a loss of lock condition
The device input pins or logic elements (LEs) can drive these input
signals. When driven high, the PLL counters reset, clearing the PLL
output and placing the PLL out of lock. The VCO sets back to its nominal
setting (~700 MHz). When driven low again, the PLL resynchronizes to
its input as it relocks. If the target VCO frequency is below this nominal
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frequency, then the output frequency starts at a higher value than desired
as the PLL locks. If the system cannot tolerate this, the clkena signal can
disable the output clocks until the PLL locks.
The pfdena signals control the phase frequency detector (PFD) output
with a programmable gate. If you disable the PFD, the VCO operates at
its last set value of control voltage and frequency with some long-term
drift to a lower frequency. The system continues running when the PLL
goes out of lock or the input clock is disabled. By maintaining the last
locked frequency, the system has time to store its current settings before
shutting down. You can either use your own control signal or a clkloss
status signal to trigger pdfena.
The clkena signals control the enhanced PLL regional and global
outputs. Each regional and global output port has its own clkena signal.
The clkena signals synchronously disable or enable the clock at the PLL
output port by gating the outputs of the g and l counters. The clkena
signals are registered on the falling edge of the counter output clock to
enable or disable the clock without glitches.
Figure 1–7 shows the waveform example for a PLL clock port enable. The
PLL can remain locked independent of the clkena signals since the looprelated counters are not affected. This feature is useful for applications
that require a low power or sleep mode. Upon re-enabling, the PLL does
not need a resynchronization or relock period. The clkena signal can
also disable clock outputs if the system is not tolerant to frequency
overshoot during resynchronization.
The extclkena signals work in the same way as the clkena signals, but
they control the external clock output counters (e0, e1, e2, and e3). Upon
re-enabling, the PLL does not need a resynchronization or relock period
unless the PLL is using external feedback mode. In order to lock in
external feedback mode, the external output must drive the board trace
back to the FBIN pin.
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Enhanced PLLs
Figure 1–7. extclkena Signals
COUNTER
OUTPUT
CLKENA
CLKOUT
Programmable Bandwidth
Enhanced PLLs provide advanced control of the PLL bandwidth using
the programmable characteristics of the PLL loop, including loop filter
and charge pump.
Background
The PLL bandwidth is the measure of the PLLs ability to track the input
clock and jitter. It is determined by the −3-dB frequency of the closed-loop
gain in the PLL or approximately the unity gain point for open loop PLL
response. As Figure 1–8 shows, these points correspond to approximately
the same frequency.
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Figure 1–8. Open- & Closed-Loop Response Bode Plots
Open-Loop Reponse Bode Plot
Increasing the PLL's
bandwidth in effect pushes
the open loop response out.
0 dB
Gain
Frequency
Closed-Loop Reponse Bode Plot
Gain
Frequency
A high-bandwidth PLL provides a fast lock time and tracks jitter on the
reference clock source, passing it through to the PLL output. A lowbandwidth PLL filters out reference clock jitter, but increases lock time.
Stratix device enhanced PLLs allow you to control the bandwidth over a
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Enhanced PLLs
finite range to customize the PLL characteristics for a particular
application. Applications that require clock switchover (such as TDMA,
frequency hopping wireless, and redundant clocking) can benefit from
the programmable bandwidth feature of the Stratix and Stratix GX PLLs.
The bandwidth and stability of such a system is determined by a number
of factors including the charge pump current, the loop filter resistor
value, the high-frequency capacitor value (in the loop filter), and the mcounter value. You can use the Quartus II software to control these factors
and to set the bandwidth to the desired value within a given range.
You can set the bandwidth to the appropriate value to balance the need
for jitter filtering and lock time. Figures 1–9 and 1–10 show the output of
a low- and high-bandwidth PLL, respectively, as it locks onto the input
clock.
Figure 1–9. Low-Bandwidth PLL Lock Time
160
155
Lock Time = 8 μs
150
145
Frequency (MHz)
140
135
130
125
120
0
5
10
15
Time (μs)
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Figure 1–10. High-Bandwidth PLL Lock Time
160
155
Lock Time = 4 μs
150
145
Frequency (MHz)
140
135
130
125
120
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Time (μs)
A high-bandwidth PLL may benefit a system with two cascaded PLLs. If
the first PLL uses spread spectrum (as user-induced jitter), the second
PLL needs a high bandwidth so it can track the jitter that is feeding it. A
low-bandwidth PLL may, in this case, lose lock due to the spread
spectrum-induced jitter on the input clock.
A low-bandwidth PLL may benefit a system using clock switchover.
When the clock switchover happens, the PLL input temporarily stops. A
low-bandwidth PLL would react more slowly to changes to its input
clock and take longer to drift to a lower frequency (caused by the input
stopping) than a high-bandwidth PLL. Figures 1–11 and 1–12
demonstrate this property.
The two plots show the effects of clock switchover with a low- or highbandwidth PLL. When the clock switchover happens, the output of the
low-bandwidth PLL (see Figure 1–11) drifts to lower frequency much
slower than the high-bandwidth PLL output (see Figures 1–12).
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Enhanced PLLs
Figure 1–11. Effect of Low Bandwidth on Clock Switchover
164
162
160
158
Frequency (MHz)
Input Clock Stops
Re-lock
156
Initial Lock
154
152
Switchover
150
0
5
10
15
20
25
30
35
40
Time (μs)
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Figure 1–12. Effect of High Bandwidth on Clock Switchover
160
Input Clock Stops
Re-lock
155
Initial Lock
150
145
Frequency (MHz)
140
135
Switchover
130
125
0
2
4
6
8
10
12
14
16
18
20
Time (μs)
Implementation
Traditionally, external components such as the VCO or loop filter control
a PLL’s bandwidth. Most loop filters are made up of passive components,
such as resistors and capacitors, which take up unnecessary board space
and increase cost. With Stratix and Stratix GX device enhanced PLLs, all
the components are contained within the device to increase performance
and decrease cost.
Stratix and Stratix GX device enhanced PLLs implement programmable
bandwidth by giving you control of the charge pump current and loop
filter resistor (R) and high-frequency capacitor (Ch) values (see
Table 1–8). The Stratix and Stratix GX device enhanced PLL bandwidth
ranges from approximately 150 kHz to 2 MHz.
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Enhanced PLLs
The charge pump current directly affects the PLL bandwidth. The higher
the charge pump current, the higher the PLL bandwidth. You can choose
from a fixed set of values for the charge pump current. Figure 1–13 shows
the loop filter and the components that you can set via the Quartus II
software.
Figure 1–13. Loop Filter Programmable Components
IUP
PFD
R
Ch
IDN
C
Software Support
The Quartus II software provides two levels of programmable bandwidth
control. The first level allows you to enter a value for the desired
bandwidth directly into the Quartus II software using the MegaWizard®
Plug-In Manager. Alternatively, you can set the bandwidth parameter in
the altpll function to the desired bandwidth. The Quartus II software
then chooses each individual bandwidth parameter to achieve the
desired setting. If designs cannot achieve the desired bandwidth setting,
the Quartus II software selects the closest achievable value. For preset
low, medium, and high bandwidth settings, the Quartus II software sets
the bandwidth as follows:
■
■
■
Low bandwidth is set at 150 KHz
Medium bandwidth is set at 800 KHz
High bandwidth is set at 2 Mhz
If you choose Auto bandwidth, the Quartus II software chooses the PLL
settings and you can get a bandwidth setting outside the 150-Khz to
2-Mhz range.
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An advanced level of control is also possible for precise control of the
loop filter parameters. This level allows you to specifically select the
charge pump current, loop filter resistor value, and loop filter (high
frequency) capacitor value. These parameters are: charge_pump_current,
loop_filter_r, and loop_filter_c. Each parameter supports the specific
range of values listed in Table 1–8.
Table 1–8. Advanced Loop Filter Parameters
Parameter
f
Values
Resistor values (kΩ)
1, 2, 3, 4, 7, 8, 9, 10
High-frequency capacitance
values (pF)
5, 10, 15, 20
Charge pump current settings
(μA)
10, 15, 20, 24, 30, 35, 40, 45, 50, 55, 60, 65,
70, 75, 80, 85, 90, 100, 112, 135, 148, 164,
212
For more information on PLL software support in the Quartus II
software, see the altpll Megafunction User Guide.
Clock Switchover
f
For more information on implementing clock switchover, see
AN 313: Implementing Clock Switchover in Stratix & Stratix GX Devices.
Spread-Spectrum Clocking
Digital clocks are generally square waves with short rise times and a 50%
duty cycle. These high-speed digital clocks concentrate a significant
amount of energy in a narrow bandwidth at the target frequency and at
the higher frequency harmonics. This results in high energy peaks and
increased electromagnetic interference (EMI). The radiated noise from
the energy peaks travels in free air and, if not minimized, can lead to
corrupted data and intermittent system errors, which can jeopardize
system reliability.
Background
Traditional methods for limiting EMI include shielding, filtering, and
multi-layer printed circuit boards (PCBs). However, these methods
significantly increase the overall system cost and sometimes are not
enough to meet EMI compliance. Spread-spectrum technology provides
a simple and effective technique for reducing EMI emissions without
additional cost and the trouble of re-designing a board.
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Spread-spectrum technology modulates the target frequency over a small
range. For example, if a 100-MHz signal has a 0.5% down-spread
modulation, then the frequency is swept from 99.5 to 100 MHz.
Figure 1–14 gives a graphical representation of the energy present in a
spread-spectrum signal as opposed to a non-spread-spectrum signal. It is
apparent that instead of concentrating the energy at the target frequency,
the energy is re-distributed across a wider band of frequencies, which
reduces peak energy.
Not only is there a reduction in the fundamental peak EMI components,
but there is also a reduction in EMI of the higher order harmonics. Since
some regulations focus on peak EMI emissions, rather than average EMI
emissions, spread-spectrum technology is a valuable method of EMI
reduction.
Figure 1–14. Spread-Spectrum Signal Energy versus Non-Spread-Spectrum Signal Energy
Spread-Spectrum Signal
Non-Spread-Spectrum Signal
Δ = ~5 dB
Amplitude
(dB)
δ = 0.5%
Frequency
(MHz)
Spread-spectrum technology would benefit a design with high EMI
emissions and/or strict EMI requirements. Device-generated EMI is
dependent on frequency, output voltage swing amplitude, and slew rate.
For example, a design using LVDS already has low EMI emissions
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General-Purpose PLLs in Stratix & Stratix GX Devices
because of the low-voltage swing. The differential LVDS signal also
allows for EMI rejection within the signal. Therefore, this situation may
not require spread-spectrum technology.
Description
Stratix and Stratix GX device enhanced PLLs feature spread-spectrum
technology to reduce the EMI emitted from the device. The enhanced PLL
provides up to a 0.5% down spread (–0.5%) using a triangular, also
known as linear, modulation profile. The modulation frequency is
programmable and ranges from approximately 30 to 150 kHz. The spread
percentage is based on the clock input to the PLL and the m and n settings.
Spread-spectrum technology reduces the peak energy by 2 to 5 dB at the
target frequency. However, this number is dependent on bandwidth and
the m and n counter values and can vary from design to design.
Spread percentage, also known as modulation width, is defined as the
percentage that the design modulates the target frequency. A negative
(–) percentage indicates a down spread, a positive (+) percentage
indicates an up spread, and a (±) indicates a center spread. Modulation
frequency is the frequency of the spreading signal or how fast the signal
sweeps from the minimum to the maximum frequency. Down-spread
modulation shifts the target frequency down by half the spread
percentage, centering the modulated waveforms on a new target
frequency.
The m and n counter values are toggled at the same time between two
fixed values. The loop filter then slowly changes the VCO frequency to
provide the spreading effect, which results in a triangular modulation.
An additional spread-spectrum counter (shown in Figure 1–15) sets the
modulation frequency. Figure 1–15 shows how spread-spectrum
technology is implemented in the Stratix device enhanced PLL.
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Figure 1–15. Spread-Spectrum Circuit Block Diagram
÷n
refclk
Up
PFD
Down
Spread
Spectrum
Counter
÷m
n count1
n count2
m count2
m count1
Figure 1–16 shows a VCO frequency waveform when toggling between
different counter values. Since the enhanced PLL switches between two
different m and n values, the result is a straight line between two
frequencies, which gives a linear modulation. The magnitude of
modulation is determined by the ratio of two m/n sets. The percent
spread is determined by:
percent spread = (fVCOmax −fVCOmin)/fVCOmax = 1 −[(m2 × n1)/(m1 × n2)]
The maximum and minimum VCO frequency is defined as:
fVCOmax = (m1/n1) × fref
fVCOmin = (m2/n2) × fref
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General-Purpose PLLs in Stratix & Stratix GX Devices
Figure 1–16. VCO Frequency Modulation Waveforms
count2 values
count1 values
VCO Frequency
Software Support
You can enter the desired down-spread percentage and modulation
frequency in the MegaWizard Plug-In Manager through the Quartus II
software. Alternatively, the MegaWizard Plug-In Manager can set the
downspread parameter in the altpll megafunction to the desired
down-spread percentage. Timing analysis ensures the design operates at
the maximum spread frequency and meets all timing requirements.
f
For more information on PLL software support in the Quartus II
software, see the altpll Megafunction User Guide.
Guidelines
If the design cascades PLLs, the source, or upstream PLL should have a
low bandwidth setting, while the destination, or downstream PLL should
have a high bandwidth setting. The upstream PLL must have a low
bandwidth setting because a PLL does not generate jitter higher than its
bandwidth. The downstream PLL must have a high bandwidth setting to
track the jitter. The design must use the spread-spectrum feature in a lowbandwidth PLL and, therefore, the Quartus II software automatically sets
the spread-spectrum PLL’s bandwidth to low.
1
Designs cannot use spread-spectrum PLLs with the
programmable bandwidth feature.
Stratix and Stratix GX devices can accept a spread-spectrum input with
typical modulation frequencies. However, the device cannot
automatically detect that the input is a spread-spectrum signal. Instead,
the input signal looks like deterministic jitter at the input of the
downstream PLL.
Spread spectrum should only have a minor effect on period jitter, but
period jitter increases. Period jitter is the deviation of a clock’s cycle time
from its previous cycle position. Period jitter measures the variation of a
clock’s output transition from its ideal position over consecutive edges.
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With down-spread modulation, the peak of the modulated waveform is
the actual target frequency. Therefore, the system never exceeds the
maximum clock speed. To maintain reliable communication, the entire
system/subsystem should use the Stratix or Stratix GX device as the clock
source. Communication could fail if the Stratix or Stratix GX logic array
is clocked by the spread-spectrum clock, but the data it receives from
another device is not.
Since spread spectrum affects the m counter values, all spread-spectrum
PLL outputs are affected. Therefore, if only one spread-spectrum signal is
needed, the clock signal should use a separate PLL without other outputs
from that PLL.
No special considerations are needed when using spread spectrum with
the clock switchover feature. This is because the clock switchover feature
does not affect the m and n counter values, which are the counter values
that are switching when using spread spectrum.
PLL Reconfiguration
f
See AN 282: Implementing PLL Reconfiguration in Stratix & Stratix GX
Devices for information on PLL reconfiguration.
Enhanced PLL Pins
Table 1–9 shows the physical pins and their purpose for the Enhanced
PLLs. For inclk port connections to pins see “Clocking” on page 1–39.
Table 1–9. Enhanced PLL Pins (Part 1 of 2)
Pin
Description
CLK4p/n
Single-ended or differential pins that can drive the inclk port for PLL 6.
CLK5p/n
Single-ended or differential pins that can drive the inclk port for PLL 6.
CLK6p/n
Single-ended or differential pins that can drive the inclk port for PLL 12.
CLK7p/n
Single-ended or differential pins that can drive the inclk port for PLL 12.
CLK12p/n
Single-ended or differential pins that can drive the inclk port for PLL 11.
CLK13p/n
Single-ended or differential pins that can drive the inclk port for PLL 11.
CLK14p/n
Single-ended or differential pins that can drive the inclk port for PLL 5.
CLK15p/n
Single-ended or differential pins that can drive the inclk port for PLL 5.
PLL5_FBp/n
Single-ended or differential pins that can drive the fbin port for PLL 5.
PLL6_FBp/n
Single-ended or differential pins that can drive the fbin port for PLL 6.
PLLENABLE
Dedicated input pin that drives the pllena port of all or a set of PLLs. If you do not
use this pin, connect it to ground.
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Table 1–9. Enhanced PLL Pins (Part 2 of 2)
Pin
Description
PLL5_OUT[3..0]p/n Single-ended or differential pins driven by extclk[3..0] ports from PLL 5.
PLL6_OUT[3..0]p/n Single-ended or differential pins driven by extclk[3..0] ports from PLL 6.
PLL11_OUT, CLK13n Single-ended output pin driven by clk0 port from PLL 11.
PLL12_OUT, CLK6n
Single-ended output pin driven by clk0 port from PLL 12.
VCCA_PLL5
Analog power for PLL 5. Connect this pin to 1.5 V, even if the PLL is not used.
VCCG_PLL5
Guard ring power for PLL 5. Connect this pin to 1.5 V, even if the PLL is not used.
GNDA_PLL5
Analog ground for PLL 5. You can connect this pin to the GND plane on the board.
GNDG_PLL5
Guard ring ground for PLL 5. You can connect this pin to the GND plane on the board.
VCCA_PLL6
Analog power for PLL 6. Connect this pin to 1.5 V, even if the PLL is not used.
VCCG_PLL6
Guard ring power for PLL 6. Connect this pin to 1.5 V, even if the PLL is not used.
GNDA_PLL6
Analog ground for PLL 6. You can connect this pin to the GND plane on the board.
GNDG_PLL6
Guard ring ground for PLL 6. You can connect this pin to the GND plane on the board.
VCCA_PLL11
Analog power for PLL 11. Connect this pin to 1.5 V, even if the PLL is not used.
VCCG_PLL11
Guard ring power for PLL 11. Connect this pin to 1.5 V, even if the PLL is not used.
GNDA_PLL11
Analog ground for PLL 11. You can connect this pin to the GND plane on the board.
GNDG_PLL11
Guard ring ground for PLL 11.You can connect this pin to the GND plane on the board.
VCCA_PLL12
Analog power for PLL 12. Connect this pin to 1.5 V, even if the PLL is not used.
VCCG_PLL12
Guard ring power for PLL 12. Connect this pin to 1.5 V, even if the PLL is not used.
GNDA_PLL12
Analog ground for PLL 12. You can connect this pin to the GND plane on the board.
GNDG_PLL12
Guard ring ground for PLL 12. You can connect this pin to the GND plane on the board.
VCC_PLL5_OUTA
External clock output VCCIO power for PLL5_OUT0p, PLL5_OUT0n, PLL5_OUT1p,
and PLL5_OUT1n outputs from PLL 5.
VCC_PLL5_OUTB
External clock output VCCIO power for PLL5_OUT2p, PLL5_OUT2n, PLL5_OUT3p,
and PLL5_OUT3n outputs from PLL 5.
VCC_PLL6_OUTA
External clock output VCCIO power for PLL5_OUT0p, PLL5_OUT0n, PLL5_OUT1p,
and PLL5_OUT1n outputs from PLL 6.
VCC_PLL6_OUTB
External clock output VCCIO power for PLL5_OUT2p, PLL5_OUT2n, PLL5_OUT3p,
and PLL5_OUT3n outputs from PLL 6.
Fast PLLs
Altera Corporation
July 2005
Stratix devices contain up to eight fast PLLs and Stratix GX devices
contain up to four fast PLLs. Both device PLLs have high-speed
differential I/O interface ability along with general-purpose features.
Figure 1–17 shows a diagram of the fast PLL. This section discusses the
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general purpose abilities of the Fast PLL. For information on the highspeed differential I/O interface capabilities, see the High-Speed Differential
I/O Interfaces in Stratix Devices chapter.
Figure 1–17. Stratix & Stratix GX Fast PLL Block Diagram
Post-Scale
Counters
diffioclk1 (2)
÷l0
VCO Phase Selection
Selectable at each PLL
Output Port
Global or
regional clock (1)
Clock
Input
Phase
Frequency
Detector
Global or
regional clock
txload_en (3)
rxload_en (3)
÷l1
Global or
regional clock
diffioclk2 (2)
PFD
Charge
Pump
8
Loop
Filter
VCO
÷g0
Global or
regional clock
÷m
Notes to Figure 1–17:
(1)
(2)
(3)
The global or regional clock input can be driven by an output from another PLL or any dedicated CLK or FCLK pin.
It cannot be driven by internally-generated global signals.
In high-speed differential I/O support mode, this high-speed PLL clock feeds the SERDES. Stratix and Stratix GX
devices only support one rate of data transfer per fast PLL in high-speed differential I/O support mode.
This signal is a high-speed differential I/O support SERDES control signal.
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Figure 1–18 shows all possible ports related to fast PLLs.
Figure 1–18. Fast PLL Ports & Physical Destinations
Fast PLL Signals
(1)
pllena
(2)
inclk0
clk[2..0]
locked
areset
pfdena
Physical Pin
Signal Driven by Internal Logic
Signal Driven to Internal Logic
Internal Clock Signal
Notes to Figure 1–18:
(1)
(2)
This input pin is shared by all enhanced and fast PLLs.
This input pin is either single-ended or differential.
Tables 1–10 and 1–11 show the description of all fast PLL ports.
Table 1–10. Fast PLL Input Signals
Name
Description
Source
Destination
inclk1
Reference clock input to PLL
Pin
PFD
pllena
Enable pin for enabling or disabling all or a set of
PLLs – active high
Pin
PLL control signal
areset
Signal used to reset the PLL which resynchronizes all the counter outputs⎯active high
Logic array
PLL control signal
pfdena
Enables the up/down outputs from the phasefrequency detector⎯active high
Logic array
PFD
Table 1–11. Fast PLL Output Signals
Name
Description
Source
Destination
clk[2..0]
PLL outputs driving regional or global clock
PLL counter
Internal clock
locked
Lock output from lock detect circuit⎯active high
PLL lock
detect
Logic array
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Clock Multiplication & Division
Stratix and Stratix GX device fast PLLs provide clock synthesis for PLL
output ports using m/(post scaler) scaling factors. The input clock is
multiplied by the m feedback factor. Each output port has a unique post
scale counter to divide down the high-frequency VCO. There is one
multiply counter, m, per fast PLL with a range of 1 to 32. There are three
post-scale counters (g0, l0, and l1) for the regional and global clock output
ports. All post-scale counters range from 1 to 32. If the design uses a
high-speed serial interface, you can set the output counter to 1 to allow
the high-speed VCO frequency to drive the SERDES.
External Clock Outputs
Each fast PLL supports differential or single-ended outputs for sourcesynchronous transmitters or for general-purpose external clocks. There
are no dedicated external clock output pins. The fast PLL global or
regional outputs can drive any I/O pin as an external clock output pin.
The I/O standards supported by any particular bank determines what
standards are possible for an external clock output driven by the fast PLL
in that bank. See the Selectable I/O Standards in Stratix & Stratix GX Devices
chapter in the Stratix Device Handbook, Volume 2 or the Stratix GX Device
Handbook, Volume 2 for output standard support.
Table 1–12 shows the I/O standards supported by fast PLL input pins.
Table 1–12. Fast PLL Port I/O Standards (Part 1 of 2)
Input
I/O Standard
INCLK
PLLENABLE
LVTTL
v
v
LVCMOS
v
v
2.5 V
v
1.8 V
v
1.5 V
v
3.3-V PCI
3.3-V PCI-X 1.0
LVPECL
v
PCML
v
LVDS
v
HyperTransport technology
v
Differential HSTL
v
1–34
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Table 1–12. Fast PLL Port I/O Standards (Part 2 of 2)
Input
I/O Standard
INCLK
PLLENABLE
Differential SSTL
3.3-V GTL
3.3-V GTL+
v
1.5-V HSTL Class I
v
1.5-V HSTL Class II
1.8-V HSTL Class I
v
1.8-V HSTL Class II
SSTL-18 Class I
v
SSTL-18 Class II
SSTL-2 Class I
v
SSTL-2 Class II
v
SSTL-3 Class I
v
SSTL-3 Class II
v
AGP (1× and 2×)
CTT
v
Phase Shifting
Stratix and Stratix GX device fast PLLs have advanced clock shift ability
to provide programmable phase shift. These parameters are set in the
Quartus II software.
The Quartus II software automatically sets the phase taps and counter
settings according to the phase shift entry. Enter a desired phase shift and
the Quartus II software automatically sets the closest setting achievable.
This type of phase shift is not reconfigurable during system operation.
You can enter a phase shift (in degrees or time units) for each PLL clock
output port or for all outputs together in one shift. You can perform phase
shifting in time units with a resolution range of 125 to 416.66 ps to create
a function of frequency input and the multiplication and division factors
(that is, it is a function of the VCO period), with the finest step being equal
to an eighth (× 0.125) of the VCO period. Each clock output counter can
choose a different phase of the VCO period from up to eight taps for
individual fine-step selection. Also, each clock output counter can use a
unique initial count setting to achieve individual coarse shift selection in
steps of one VCO period. The combination of coarse and grain shifts
allows phase shifting for the entire input clock period.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Fast PLLs
The equation to determine the precision of phase in degrees is: 45° ÷ postscale counter value. Therefore, the maximum step size is 45° , and smaller
steps are possible depending on the multiplication and division ratio
necessary on the output counter port.
This type of phase shift provides the highest precision since it is the least
sensitive to process, supply, and temperature variation.
Programmable Duty Cycle
The programmable duty cycle allows the fast PLL to generate clock
outputs with a variable duty cycle. This feature is supported on each fast
PLL post-scale counter. g0, l0, and l1 all support programmable duty. You
use a low- and high-time count setting for the post-scale counters to set
the duty cycle.
The Quartus II software uses the frequency input and multiply/divide
rate desired to select the post-scale counter, which determines the
possible choices for each duty cycle. The precision of the duty cycle is
determined by the post-scale counter value chosen on an output. The
precision is defined by 50% divided by the post-scale counter value. The
closest value to 100% is not achievable for a given counter value. For
example, if the g0 counter is 10, then steps of 5% are possible for duty
cycle choices between 5 to 90%.
If the device uses external feedback, you must set the duty cycle for the
counter driving off the device to 50%.
Control Signals
The lock output indicates a stable clock output signal in phase with the
reference clock. Unlike enhanced PLLs, fast PLLs do not have a lock filter
counter.
The pllenable pin is a dedicated pin that enables/disables both PLLs.
When the pllenable pin is low, the clock output ports are driven by
GND and all the PLLs go out of lock. When the pllenable pin goes high
again, the PLLs relock and resynchronize to the input clocks. You can
choose which PLLs are controlled by the pllenable by connecting the
pllenable input port of the altpll megafunction to the common
pllenable input pin.
The areset signals are reset/resynchronization inputs for each fast PLL.
The Stratix and Stratix GX devices can drive these input signals from an
input pin or from LEs. When driven high, the PLL counters reset, clearing
the PLL output and placing the PLL out of lock. The VCO sets back to its
nominal setting (~700 MHz). When driven low again, the PLL
1–36
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Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
resynchronizes to its input clock as it relocks. If the target VCO frequency
is below this nominal frequency, then the output frequency starts at a
higher value then desired as it locks.
The pfdena signals control the PFD output with a programmable gate. If
you disable the PFD, the VCO operates at its last set value of control
voltage and frequency with some long-term drift to a lower frequency.
The system continues running when the PLL goes out of lock or the input
clock disables. By maintaining the last locked frequency, the system has
time to store its current settings before shutting down.
If the PLL loses lock for any reason (for example, because of excessive
inclk jitter, clock switchover, PLL reconfiguration, or power supply
noise), the PLL must be reset with the areset signal to guarantee correct
phase relationship between the PLL output clocks. If the phase
relationship between the input clock and the output clock and between
different output clocks from the PLL is not important in your design, it is
not necessary to reset the PLL.
Pins
Table 1–13 shows the physical pins and their purpose for the Fast PLLs.
For inclk port connections to pins see “Clocking” on page 1–39.
Table 1–13. Fast PLL Pins (Part 1 of 3)
Pin
Description
CLK0p/n
Single-ended or differential pins that can drive the inclk port for PLL 1 or 7.
CLK1p/n
Single-ended or differential pins that can drive the inclk port for PLL 1.
CLK2p/n
Single-ended or differential pins that can drive the inclk port for PLL 2 or 8.
CLK3p/n
Single-ended or differential pins that can drive the inclk port for PLL 2.
CLK8p/n
Single-ended or differential pins that can drive the inclk port for PLL 3 or 9. (1)
CLK9p/n
Single-ended or differential pins that can drive the inclk port for PLL 3. (1)
CLK10p/n
Single-ended or differential pins that can drive the inclk port for PLL 4 or 10. (1)
CLK11p/n
Single-ended or differential pins that can drive the inclk port for PLL 4. (1)
FPLL7CLKp/n
Single-ended or differential pins that can drive the inclk port for PLL 7.
FPLL8CLKp/n
Single-ended or differential pins that can drive the inclk port for PLL 8.
FPLL9CLKp/n
Single-ended or differential pins that can drive the inclk port for PLL 9. (1)
FPLL10CLKp/n
Single-ended or differential pins that can drive the inclk port for PLL 10. (1)
PLLENABLE
Dedicated input pin that drives the pllena port of all or a set of PLLs. If you do not
use this pin, connect it to ground.
VCCA_PLL1
Analog power for PLL 1. Connect this pin to 1.5 V, even if the PLL is not used.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Fast PLLs
Table 1–13. Fast PLL Pins (Part 2 of 3)
Pin
Description
VCCG_PLL1
Guard ring power for PLL 1. Connect this pin to 1.5 V, even if the PLL is not used.
GNDA_PLL1
Analog ground for PLL 1. You can connect this pin to the GND plane on the board.
GNDG_PLL1
Guard ring ground for PLL 1. You can connect this pin to the GND plane on the
board.
VCCA_PLL2
Analog power for PLL 2. Connect this pin to 1.5 V, even if the PLL is not used.
VCCG_PLL2
Guard ring power for PLL 2. Connect this pin to1.5 V, even if the PLL is not used.
GNDA_PLL2
Analog ground for PLL 2. You can connect this pin to the GND plane on the board.
GNDG_PLL2
Guard ring ground for PLL 2. You can connect this pin to the GND plane on the
board.
VCCA_PLL3
Analog power for PLL 3. Connect this pin to 1.5 V, even if the PLL is not used. (1)
VCCG_PLL3
Guard ring power for PLL 3. Connect this pin to 1.5 V, even if the PLL is not
used. (1)
GNDA_PLL3
Analog ground for PLL 3. You can connect this pin to the GND plane on the
board. (1)
GNDG_PLL3
Guard ring ground for PLL 3. You can connect this pin to the GND plane on the
board. (1)
VCCA_PLL4
Analog power for PLL 4. Connect this pin to 1.5 V, even if the PLL is not used. (1)
VCCG_PLL4
Guard ring power for PLL 4. Connect this pin to 1.5 V, even if the PLL is not
used. (1)
GNDA_PLL4
Analog ground for PLL 4. You can connect this pin to the GND plane on the
board. (1)
GNDG_PLL4
Guard ring ground for PLL 4. You can connect this pin to the GND plane on the
board. (1)
VCCA_PLL7
Analog power for PLL 7. Connect this pin to 1.5 V, even if the PLL is not used.
VCCG_PLL7
Guard ring power for PLL 7. Connect this pin to 1.5 V, even if the PLL is not used.
GNDA_PLL7
Analog ground for PLL 7. You can connect this pin to the GND plane on the board.
GNDG_PLL7
Guard ring ground for PLL 7. You can connect this pin to the GND plane on the
board.
VCCA_PLL8
Analog power for PLL 8. Connect this pin to 1.5 V, even if the PLL is not used.
VCCG_PLL8
Guard ring power for PLL 8. Connect this pin to 1.5 V, even if the PLL is not used.
GNDA_PLL8
Analog ground for PLL 8. You can connect this pin to the GND plane on the board.
GNDG_PLL8
Guard ring ground for PLL 8. You can connect this pin to the GND plane on the
board.
VCCA_PLL9
Analog power for PLL 9. Connect this pin to 1.5 V, even if the PLL is not used. (1)
VCCG_PLL9
Guard ring power for PLL 9. Connect this pin to 1.5 V, even if the PLL is not
used. (1)
1–38
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Table 1–13. Fast PLL Pins (Part 3 of 3)
Pin
Description
GNDA_PLL9
Analog ground for PLL 9. You can connect this pin to the GND plane on the
board. (1)
GNDG_PLL9
Guard ring ground for PLL 9. You can connect this pin to the GND plane on the
board. (1)
VCCA_PLL10
Analog power for PLL 10. Connect this pin to 1.5 V, even if the PLL is not
used. (1)
VCCG_PLL10
Guard ring power for PLL 10. Connect this pin to 1.5 V, even if the PLL is not
used. (1)
GNDA_PLL10
Analog ground for PLL 10. Connect this pin to the GND plane on the board. (1)
GNDG_PLL10
Guard ring ground for PLL 10. You can connect this pin to the GND plane on the
board. (1)
Note to Table 1–13:
(1)
PLLs 3, 4, 9, and 10 are not available on Stratix GX devices for general-purpose configuration. These PLLs are part
of the HSSI block. See AN 236: Using Source-Synchronous Signaling with DPA in Stratix GX Devices for more
information.
Clocking
Stratix and Stratix GX devices provide a hierarchical clock structure and
multiple PLLs with advanced features. The large number of clocking
resources in combination with the clock synthesis precision provided by
enhanced and fast PLLs provides a complete clock management solution.
Global & Hierarchical Clocking
Stratix and Stratix GX devices provide 16 dedicated global clock
networks, 16 regional clock networks (4 per device quadrant), and
8 dedicated fast regional clock networks. These clocks are organized into
a hierarchical clock structure that allows for up to 22 clocks per device
region with low skew and delay. This hierarchical clocking scheme
provides up to 48 unique clock domains within Stratix and Stratix GX
devices.
There are 16 dedicated clock pins (CLK[15..0]) on Stratix devices and
12 dedicated clock pins (CLK[11..0]) on Stratix GX devices to drive
either the global or regional clock networks. Four clock pins drive each
side of the Stratix device, as shown in Figures 1–19 and 1–20. On Stratix
GX devices, four clock pins drive the top, left, and bottom sides of the
device. The clocks on the right side of the device are not available for
general-purpose PLLs. Enhanced and fast PLL outputs can also drive the
global and regional clock networks.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Clocking
Global Clock Network
These clocks drive throughout the entire device, feeding all device
quadrants. All resources within the device—IOEs, LEs, DSP blocks, and
all memory blocks—can use the global clock networks as clock sources.
These resources can also be used for control signals, such as clock enables
and synchronous or asynchronous clears fed from the external pin.
Internal logic can also drive the global clock networks for internally
generated global clocks and asynchronous clears, clock enables, or other
control signals with large fanout. Figure 1–19 shows the 16 dedicated CLK
pins driving global clock networks.
Figure 1–19. Global Clocking
CLK[15..12]
Global Clock [15..0]
CLK[3..0]
Global Clock [15..0]
CLK[11..8]
CLK[7..4]
Regional Clock Network
There are four regional clock networks within each quadrant of the
Stratix or Stratix GX device that are driven by the same dedicated
CLK[15..0] input pins or from PLL outputs. From a top view of the
silicon, RCLK[0..3] are in the top-left quadrant, RCLK[8..11] are in
the top-right quadrant, RCLK[4..7] are in the bottom-left quadrant, and
1–40
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
RCLK[12..15] are in the bottom-right quadrant. The regional clock
networks only pertain to the quadrant they drive into. The regional clock
networks provide the lowest clock delay and skew for logic contained
within a single quadrant. RCLK clock networks cannot be driven by
internal logic. The CLK clock pins symmetrically drive the RCLK networks
within a particular quadrant, as shown in Figure 1–20. See Figures 1–21
and 1–22 for RCLK connections from PLLs and CLK pins.
Figure 1–20. Regional Clocks
RCLK[2..3]
RCLK[11..10]
CLK[15..12]
RCLK[9..8]
RCLK[1..0]
CLK[3..0]
CLK[11..8]
RCLK[14..15]
RCLK[4..5]
CLK[7..4]
Regional Clocks Only Drive a Device
Quadrant from Specified CLK Pins or
PLLs within that Quadrant
RCLK[6..7]
RCLK[12..13]
Clock Input Connections
Two CLK pins drive each enhanced PLL. You can use either one or both
pins for clock switchover inputs into the PLL. Either pin can be the
primary clock source for clock switchover, which is controlled in the
Quartus II software. Enhanced PLLs 5 and 6 also have feedback input
pins as shown in Table 1–14.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Clocking
Input clocks for fast PLLs 1, 2, 3, and 4 come from CLK pins. Stratix GX
devices use PLLs 3 and 4 in the HSSI block only. A multiplexer chooses
one of two possible CLK pins to drive each PLL. This multiplexer is not a
clock switchover multiplexer and is only used for clock input
connectivity.
Either a FPLLCLK input pin or a CLK pin can drive the fast PLLs in the
corners (7, 8, 9, and 10) when used for general purpose. CLK pins cannot
drive these fast PLLs in high-speed differential I/O mode. PLLs 9 and 10
are used for the HSSI block in Stratix GX devices and are not available.
Table 1–14 shows which PLLs are available for each Stratix device and
which input clock pin drives which PLLs.
Table 1–14. Stratix Clock Input Sources For Enhanced & Fast PLLs (Part 1 of 2)
EP1S30, EP1S40, EP1S60 &
EP1S80 Devices Only
All Stratix Devices
Clock Input
Pins
EP1S40 (3),
EP1S60 &
EP1S80
Devices Only
PLL 1 PLL 2 PLL 3 PLL 4 PLL 5 PLL 6 PLL 7 PLL 8 PLL 9 PLL
PLL
PLL
(1)
(1)
(1)
(1)
(2)
(2)
(1)
(1)
(1) 10 (1) 11 (2) 12 (2)
CLK0p/n
v
CLK1p/n
v
v
CLK2p/n
v
CLK3p/n
v
v
CLK4p/n
v
CLK5p/n
v
CLK6p/n
v
CLK7p/n
v
CLK8p/n
v
CLK9p/n
v
v
CLK10p/n
v
CLK11p/n
v
v
CLK12p/n
v
CLK13p/n
v
CLK14p/n
v
CLK15p/n
v
1–42
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Table 1–14. Stratix Clock Input Sources For Enhanced & Fast PLLs (Part 2 of 2)
EP1S30, EP1S40, EP1S60 &
EP1S80 Devices Only
All Stratix Devices
Clock Input
Pins
EP1S40 (3),
EP1S60 &
EP1S80
Devices Only
PLL 1 PLL 2 PLL 3 PLL 4 PLL 5 PLL 6 PLL 7 PLL 8 PLL 9 PLL
PLL
PLL
(1)
(1)
(1)
(1)
(2)
(2)
(1)
(1)
(1) 10 (1) 11 (2) 12 (2)
v
FPll7clk
v
FPll8clk
v
FPll9clk
v
FPll10clk
Clock Feedback Input Pins
Pll5_fbp/n
Pll6_fbp/n
v
v
Notes to Table 1–14:
(1)
(2)
(3)
This is a fast PLL. The global or regional clocks in a fast PLL’s quadrant can drive the fast PLL input. A pin or other
PLL must drive the global or regional source. The source cannot be driven by internally generated logic before
driving the fast PLL.
This is an enhanced PLL.
The EP1S40 device in the F780 package does not support PLLs 11 and 12.
Clock Output Connections
Enhanced PLLs have outputs for two regional clock outputs and four
global outputs. There is line sharing between clock pins, global and
regional clock networks and all PLL outputs. Check Tables 1–15 and 1–16
and Figures 1–21 and 1–22 to make sure that the clocking scheme is valid.
The Quartus II software automatically maps to regional and global clocks
to avoid any restrictions. Enhanced PLLs 5 and 6 drive out to singleended pins as shown in Table 1–15. PLLs 11 and 12 drive out to singleended pins.
You can connect each fast PLL 1, 2, 3, or 4 outputs (g0, l0, and l1) to either
a global or a regional clock. (PLLs 3 and 4 are not available on Stratix GX
devices.) There is line sharing between clock pins, FPLLCLK pins, global
and regional clock networks and all PLL outputs. Check Figures 1–21 and
1–22 to make sure that the clocking is valid. The Quartus II software
automatically maps to regional and global clocks to avoid any
restrictions.
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July 2005
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Stratix Device Handbook, Volume 2
Clocking
Table 1–15 shows the global and regional clocks that each PLL drives
outputs to for Stratix devices. Table 1–16 shows the global and regional
clock network each of the CLK and FPLLCLK pins drive when bypassing
the PLL.
Table 1–15. Stratix Global & Regional Clock Output Line Sharing for Enhanced & Fast PLLs (Part 1 of 2)
EP1S30, EP1S40, EP1S60 &
EP1S80 Devices Only
All Devices
Clock
Network
EP1S40 (5),
EP1S60 &
EP1S80
Devices Only
PLL 1 PLL 2 PLL 3 PLL 4 PLL 5 PLL 6 PLL 7 PLL 8 PLL PLL
PLL
PLL
(1)
(1)
(1)
(1)
(2)
(2)
(1)
(1) 9 (1) 10 (1) 11 (2) 12 (2)
GCLK0
v
v
v
v
GCLK1
v
v
v
v
GCLK2
v
v
v
v
GCLK3
v
v
v
v
GCLK4
v
v
GCLK5
v
v
GCLK6
v
v
GCLK7
v
v
GCLK8
v
v
v
v
GCLK9
v
v
v
v
GCLK10
v
v
v
v
GCLK11
v
v
v
v
GCLK12
v
v
GCLK13
v
v
GCLK14
v
v
GCLK15
v
v
RCLK0
v
v
v
RCLK1
v
v
v
RCLK2
v
v
RCLK3
v
v
RCLK4
v
v
v
RCLK5
v
v
v
1–44
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Table 1–15. Stratix Global & Regional Clock Output Line Sharing for Enhanced & Fast PLLs (Part 2 of 2)
EP1S30, EP1S40, EP1S60 &
EP1S80 Devices Only
All Devices
Clock
Network
EP1S40 (5),
EP1S60 &
EP1S80
Devices Only
PLL 1 PLL 2 PLL 3 PLL 4 PLL 5 PLL 6 PLL 7 PLL 8 PLL PLL
PLL
PLL
(1)
(1)
(1)
(1)
(2)
(2)
(1)
(1) 9 (1) 10 (1) 11 (2) 12 (2)
RCLK6
v
v
RCLK7
v
v
RCLK8
v
v
v
RCLK9
v
v
v
RCLK10
v
v
RCLK11
v
v
RCLK12
v
v
RCLK13
v
v
RCLK14
v
v
v
RCLK15
v
v
v
External Clock Output
PLL5_OUT
[3..0]p/n
PLL6_OUT
[3..0]p/n
v
v
PLL11_OUT
v
(3)
PLL12_OUT
v
(4)
Notes to Table 1–15:
(1)
(2)
(3)
(4)
(5)
This is a fast PLL.
This is an enhanced PLL.
This pin is a tri-purpose pin; it can be an I/O pin, CLK13n, or used for PLL 11 output.
This pin is a tri-purpose pin; it can be an I/O pin, CLK7n, or used for PLL 12 output.
The EP1S40 device in the F780 package does not support PLLs 11 and 12.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Clocking
Table 1–16. Stratix CLK & FPLLCLK Input Pin Connections to Global & Regional Clock Networks Note (1)
CLK Pins
FPLLCLK (2)
Clock Network
0
GCLK0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
v
v v
v
GCLK4
v
GCLK5
v
GCLK6
v
GCLK7
v
GCLK8
v v
v
GCLK9
v v
v
GCLK10
v v
v
GCLK11
v v
v
GCLK12
v
GCLK13
v
GCLK14
v
GCLK15
v
v
v
v
v
RCLK2
RCLK5
v
v
RCLK3
RCLK4
10
v v
v
GCLK3
RCLK1
9
v v
v
GCLK2
RCLK0
8
v v
v
GCLK1
7
v
v
v
RCLK6
RCLK7
v
v
v
RCLK8
v
RCLK9
v
v
RCLK11
1–46
Stratix Device Handbook, Volume 2
v
v
RCLK10
RCLK12
v
v
v
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Table 1–16. Stratix CLK & FPLLCLK Input Pin Connections to Global & Regional Clock Networks Note (1)
CLK Pins
FPLLCLK (2)
Clock Network
0
RCLK13
RCLK14
RCLK15
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
7
8
9
10
v
v
v
Notes to Table 1–16:
(1)
(2)
The CLK and FPLLCLK pins cannot drive.
The FPLLCLK pin is only available in EP1S80, EP1S60, EP1S40, and EP1S30 devices.
The fast PLLs also drive high-speed SERDES clocks for differential I/O
interfacing. For information on these FPLLCLK pins, see the High-Speed
Differential I/O Interfaces in Stratix Devices chapter.
Figure 1–21 shows the global and regional clock input and output
connections from the enhanced. Figure 1–21 shows graphically the same
information as Tables 1–15 and 1–16 but with the added detail of where
each specific PLL output port drives to.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Clocking
Figure 1–21. Global & Regional Clock Connections from Side Clock Pins & Fast PLL Outputs
RCLK1
RCLK0
FPLL7CLK
G3
G1
G0
G2
G8
G9
G10
G11
RCLK9
RCLK8
l0
l0
PLL 7 l1
CLK0
CLK1
g0
g0
l0
l0
PLL 1 l1
l1 PLL 4
g0
CLK2
CLK3
CLK10
CLK11
g0
l02
PLL 2 l1
g0
2l0
l1 PLL 3
g0
l0
FPLL8CLK
FPLL10CLK
l1 PLL 10
CLK8
CLK9
l0
PLL 8 l1
g0
l1 PLL 9
g0
RCLK4
RCLK5
Regional
Clocks
FPLL9CLK
RCLK14
Global
Clocks
RCLK15
Regional
Clocks
Notes to Figures 1–21:
(1)
(2)
The global or regional clocks in a fast PLL’s quadrant can drive the fast PLL input. A dedicated pin or other PLL
must drive the global or regional source. The source cannot be driven by internally generated logic before driving
the fast PLL.
PLLs 3, 4, 9, and 10 are used for the HSSI block in Stratix GX devices and are not available for this use.
When using a fast PLL to compensate for clock delays to drive logic on
the chip, the clock delay from the input pin to the clock input port of the
PLL is compensated only if the clock is fed by the dedicated input pin
closest to the PLL. If the fast PLL gets its input clock from a global or
regional clock or from another dedicated clock pin, which does not
directly feed the fast PLL, the clock signal is first routed onto a global
clock network. The signal then drives into the PLL. In this case, the clock
delay is not fully compensated and the delay compensation is equal to the
clock delay from the dedicated clock pin closest to the PLL to the clock
input port of the PLL.
For example, if you use CLK0 to feed PLL 7, the input clock path delay is
not fully compensated, but if FPLL7CLK feeds PLL 7, the input clock path
delay is fully compensated.
Figure 1–22 shows the global and regional clock input and output
connections from the fast PLLs. Figure 1–22 shows graphically the same
information as Tables 1–15 and 1–16 but with the added detail of where
each specific PLL output port drives to.
1–48
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Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Figure 1–22. Global & Regional Clock Connections from Top Clock Pins & Enhanced PLL Outputs
PLL5_OUT[3..0] CLK14 (1)
PLL5_FB
CLK15 (2)
CLK12 (1)
CLK13 (2)
E[0..3]
PLL 5
PLL 11
L0 L1 G0 G1 G2 G3
G0 G1 G2 G3 L0 L1
PLL11_OUT
RCLK10
RCLK11
Regional
Clocks
RCLK2
RCLK3
G12
G13
G14
G15
Global
Clocks
Regional
Clocks
G4
G5
G6
G7
RCLK6
RCLK7
RCLK12
RCLK13
PLL12_OUT
L0 L1 G0 G1 G2 G3
G0 G1 G2 G3 L0 L1
PLL 6
PLL6_OUT[3..0]
PLL 12
PLL6_FB
CLK4 (1)
CLK6 (1)
CLK7 (2)
CLK5 (2)
Notes to Figures 1–22:
(1)
(2)
CLK4, CLK6, CLK12, and CLK14 feed the corresponding PLL’s inclk0 port.
CLK5, CLK7, CLK13, and CLK15 feed the corresponding PLL’s inclk1 port.
Altera Corporation
July 2005
1–49
Stratix Device Handbook, Volume 2
Board Layout
Board Layout
The enhanced and fast PLL circuits in Stratix and Stratix GX devices
contain analog components embedded in a digital device. These analog
components have separate power and ground pins to minimize noise
generated by the digital components. Both Stratix and Stratix GX
enhanced and fast PLLs use separate VCC and ground pins to isolate
circuitry and improve noise resistance.
VCCA & GNDA
Each enhanced and fast PLL uses separate VCC and ground pin pairs for
their analog circuitry. The analog circuit power and ground pin for each
PLL is called PLL<PLL number>_VCCA and PLL<PLL number>_GNDA.
Connect the VCCA power pin to a 1.5-V power supply, even if you do not
use the PLL. Isolate the power connected to VCCA from the power to the
rest of the Stratix and Stratix GX device or any other digital device on the
board. You can use one of three different methods of isolating the VCCA
pin: separate VCCA power planes, a partitioned VCCA island within the
VCCINT plane, and thick VCCA traces.
Separate VCCA Power Plane
A mixed signal system is already partitioned into analog and digital
sections, each with its own power planes on the board. To isolate the
VCCA pin using a separate VCCA power plane, connect the VCCA pin to the
analog 1.5-V power plane.
Partitioned VCCA Island within VCCINT Plane
Fully digital systems do not have a separate analog power plane on the
board. Because it is expensive to add new planes to the board, you can
create islands for VCCA_PLL. Figure 1–23 shows an example board layout
with an analog power island. The dielectric boundary that creates the
island should be 25 mils thick. Figure 1–23 shows a partitioned plane
within VCCINT for VCCA.
1–50
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Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Figure 1–23. VCCINT Plane Partitioned for VCCA Island
Thick VCCA Trace
Because of board constraints, you might not be able to partition a VCCA
island. Instead, run a thick trace from the power supply to each VCCA pin.
The traces should be at least 20 mils thick.
In each of these three cases, you should filter each VCCA pin with a
decoupling circuit shown in Figure 1–24. Place a ferrite bead that exhibits
high impedance at frequencies of 50 MHz or higher and a 10-μF tantalum
parallel capacitor where the power enters the board. Decouple each VCCA
pin with a 0.1-μF and 0.001-μF parallel combination of ceramic capacitors
located as close as possible to the Stratix or Stratix GX device. You can
connect the GNDA pins directly to the same ground plane as the device’s
digital ground.
Altera Corporation
July 2005
1–51
Stratix Device Handbook, Volume 2
Board Layout
Figure 1–24. PLL Power Schematic for Stratix or Stratix GX PLLs
Ferrite
Bead
1.5-V Supply
10 μF
PLL<PLL number>_VCCA
0.1 μF
0.001 μF
PLL<PLL number>_GNDA
VCCINT
PLL<PLL number>_VCCG
Repeat for Each PLL
Power and Ground Set
PLL<PLL number>_GNDG
Stratix Device
VCCG & GNDG
The guard ring power and ground pins are called
PLL<PLL number>_VCCG and PLL<PLL number>_GNDG. The guard ring
isolates the PLL circuit from the rest of the device. Connect these guard
ring VCCG pins to the quietest digital supply on the board. In most
systems, this is the digital 1.5-V supply supplied to the device's VCCINT
pins. Connect the VCCG pins to a power supply even if you do not use the
PLL. You can connect the GNDG pins directly to the same ground plane as
the device’s digital ground. See Figure 1–24.
1–52
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
External Clock Output Power
Enhanced PLLs 5 and 6 also have isolated power pins for their dedicated
external clock outputs (VCC_PLL5_OUTA and VCC_PLL5_OUTB, or
VCC_PLL6_OUTA and VCC_PLL6_OUTB, respectively). PLLs 5 and 6 both
have two banks of outputs. Each bank is powered by a unique output
power, OUTA or OUTB, as illustrated in Figure 1–25. These outputs can by
powered by 3.3, 2.5, 1.8, or 1.5 V depending on the I/O standard for the
clock output in the A or B groups.
Altera Corporation
July 2005
1–53
Stratix Device Handbook, Volume 2
Board Layout
Figure 1–25. External Clock Output Pin Association to Output Power Note (1)
VCC_PLL5_OUTA
PLL5_OUT0p
PLL5_OUT0n
PLL5_OUT0p
PLL5_OUT0n
VCC_PLL5_OUTB
PLL5_OUT2p
PLL5_OUT2n
PLL5_OUT3p
PLL5_OUT3n
Note to Figure 1–25:
(1)
These pins apply to PLL 5. The figure for PLL 6 is similar, except that the pin names
begin with the prefix PLL6 instead of PLL5.
1–54
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
General-Purpose PLLs in Stratix & Stratix GX Devices
Filter each isolated power pin with a decoupling circuit shown in
Figure 1–26. Decouple the isolated power pins with a 0.1-μF and a
0.001-μF parallel combination of ceramic capacitors located as close as
possible to the Stratix device.
Figure 1–26. Stratix PLL External Clock Output Power Ball Connections
Note (1)
VCCIO
Supply
VCC_PLL5_OUTA
0.1 μF
0.001 μF
VCC_PLL5_OUTB
0.1 μF
0.001 μF
Stratix Device
Note to Figure 1–26:
(1)
Altera Corporation
July 2005
Figure 1–26 also applies to VCC_PLL6_OUTA/B.
1–55
Stratix Device Handbook, Volume 2
Conclusion
Guidelines
Use the following guidelines for optimal jitter performance on the
external clock outputs from enhanced PLLs 5 and 6. If all outputs are
running at the same frequency, these guidelines are not necessary to
improve performance.
■
■
■
When driving two or more clock outputs from PLL 5 or 6, separate
the outputs into the two groups shown in Figure 1–24. For example,
if you are driving 100- and 200-MHz clock outputs off-chip from PLL
5, place one output on PLL5_OUT0p (powered by VCC_PLL5_OUTA)
and the other output on PLL5_OUT2p (powered by
VCC_PLL5_OUTB). Since the output buffers are powered by different
pins, they are less susceptible to bimodal jitter. Bimodal jitter is a
deterministic jitter not caused by the PLL but rather by coincident
edges of clock outputs that are multiples of each other.
Use phase shift to ensure edges are not coincident on all the clock
outputs.
Use phase shift to skew clock edges with respect to each other for
best jitter performance.
1
■
Conclusion
Delay shift (time delay elements) are no longer supported
in Stratix PLLs. Use the phase shift feature to implement the
desired time shift.
If you cannot drive multiple clocks of different frequencies and
phase shifts or isolate banks, you should control the drive capability
on the lower frequency clock. Reducing how much current the
output buffer has to supply can reduce the noise. Minimize
capacitive load on the slower frequency output and configure the
output buffer to drive slow slew rate and lower current strength. The
higher frequency output should have an improved performance, but
this may degrade the performance of your lower frequency clock
output.
Stratix and Stratix GX device enhanced PLLs provide you with complete
control of your clocks and system timing. These PLLs are capable of
offering flexible system level clock management that was previously only
available in discrete PLL devices. The embedded PLLs meet and exceed
the features offered by these high-end discrete devices, reducing the need
for other timing devices in the system.
1–56
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Section II. Memory
This section provides information on the TriMatrix™ Embedded Memory
blocks internal to Stratix® devices and the supported external memory
interfaces.
It contains the following chapters:
■
Chapter 2, TriMatrix Embedded Memory Blocks in
Stratix & Stratix GX Devices
■
Chapter 3, External Memory Interfaces in Stratix & Stratix GX
Devices
The QDR SRAM Controller Reference Design for Stratix & Stratix GX Devices
chapter is removed in this version of the Stratix Device Handbook. The
information is available in AN 349: Interfacing QDR SRAM with Stratix and
Stratix GX Devices.
Revision History
The table below shows the revision history for Chapters 2 and 3.
Chapter
Date/Version
Changes Made
2
July 2005, v3.3
●
Updated “Implementing True Dual-Port Mode” section.
January 2005,
v3.2
●
Minor technical content update.
September
2004, v3.1
●
Updated Note 1 in Figure 2–12 on page 2–22.
Updated description about using two different clocks in a
dual-port RAM on page 2–27.
Deleted description of M-RAM block and document
references on page 2–27.
●
●
April 2004, v3.0
●
●
●
July 2003, v2.0
●
●
●
Altera Corporation
Comments
Synchronous occurrences are renamed to pipelined.
Pseudo-synchronous occurrences are renamed flowthrough.
Added AND gate to Figure 2–12.
Updated performance specification for TriMatrix memory
in Table 2-1.
Added addressing example for a RAM that is using
mixed-width mode, page 2-9.
Added Note 1 to Tables 2-9 and 2-10, Note 3 to Figure 211, and Note 2 to Figures 2-12 and 2-13.
Section II–1
Memory
Stratix Device Handbook, Volume 2
Chapter
Date/Version
3
June 2006, v3.3
Changes Made
●
●
July 2005, v3.2
●
●
September
2004, v3.1
●
●
●
●
●
●
●
April 2004, v3.0
●
●
●
●
●
●
Updated mathematical symbols in Table 3–3.
Updated “DQS Phase-Shift Circuitry” section.
Moved Figure 8 to become Figure 1, “Example of Where
a DQS Signal is Center-Aligned in the IOE” on page 3–3.
Updated Table 3–1 on page 3–10, updated Note 4. Note
4, 5, and 6, are now Note 5, 6, and 7, respectively.
Updated Table 3–2 on page 3–10.
Updated Table 3–3 on page 3–13.
Updated Note on page 3–14.
Moved the “External Memory Standards” on page 3–1 to
follow the Introduction section.
Moved “Conclusion” on page 3–27 to end of chapter.
Chapter renamed Chapter 3, External Memory Interfaces
in Stratix & Stratix GX Devices.
Table 3–1: DDR SDRAM - side banks row added, ZBT
SRAM row updated.
Added Tables 3–2 and 3–4.
DQSn pins removed (page 3-5)
Deleted “QDR SRAM Interfacing” figure.
Replaced “tZX & tXZ Timing Diagram.”
●
Removed support for series and parallel on-chip
termination.
July 2003, v2.0
●
altddio_bidir function is used for DQS in versions before
Quartus II 3.0. (page 3-2)
Updated naming convention for DQS pins on page 3-9 to
match pin tables.
Clarified input clock to PLL must come from an external
input pin on page 3-12.
●
Section II–2
Changed the name of the chapter from External Memory
Interfaces to External Memory Interfaces in Stratix &
Stratix GX Devices to reflect its shared status between
those device handbooks.
Added cross reference regarding frequency limits for 72
and 90° phase shift for DQS.
November 2003,
v2.1
●
Comments
Altera Corporation
2. TriMatrix Embedded
Memory Blocks in
Stratix & Stratix GX Devices
S52003-3.3
Introduction
Stratix® and Stratix GX devices feature the TriMatrix™ memory
structure, composed of three sizes of embedded RAM blocks. TriMatrix
memory includes 512-bit M512 blocks, 4-Kbit M4K blocks, and 512-Kbit
M-RAM blocks, each of which is configurable to support a wide range of
features. Offering up to 10 Mbits of RAM and up to 12 terabits per second
of device memory bandwidth, the TriMatrix memory structure makes the
Stratix and Stratix GX families ideal for memory-intensive applications.
TriMatrix
Memory
TriMatrix memory structures can implement a wide variety of complex
memory functions. For example, use the small M512 blocks for first-in
first-out (FIFO) functions and clock domain buffering where memory
bandwidth is critical. The M4K blocks are an ideal size for applications
requiring medium-sized memory, such as asynchronous transfer mode
(ATM) cell processing. M-RAM blocks enhance programmable logic
device (PLD) memory capabilities for large buffering applications, such
as internet protocol (IP) packet buffering and system cache.
TriMatrix memory blocks support various memory configurations,
including single-port, simple dual-port, true dual-port (also known as
bidirectional dual-port), shift-register, ROM, and FIFO mode. The
TriMatrix memory architecture also includes advanced features and
capabilities, such as byte enable support, parity-bit support, and mixedport width support. This chapter describes the various TriMatrix memory
modes and features.
Table 2–1 summarizes the features supported by the three sizes of
TriMatrix memory.
f
Altera Corporation
July 2005
For more information on selecting which memory block to use, see
AN 207: TriMatrix Memory Selection Using the Quartus II Software.
2–1
TriMatrix Memory
Table 2–1. Summary of TriMatrix Memory Features
Feature
Performance
Total RAM bits (including parity bits)
Configurations
Parity bits
M512 Block
M4K Block
M-RAM Block
319 MHz
290 MHz
287 MHz
576
4,608
589,824
512 × 1
256 × 2
128 × 4
64 × 8
64 × 9
32 × 16
32 × 18
4K × 1
2K × 2
1K × 4
512 × 8
512 × 9
256 × 16
256 × 18
128 × 32
128 × 36
64K × 8
64K × 9
32K × 16
32K × 18
16K × 32
16K × 36
8K × 64
8K × 72
4K × 128
4K × 144
v
v
v
v
v
Byte enable
Single-port memory
v
v
v
Simple dual-port memory
v
v
v
v
v
True dual-port memory
Embedded shift register
v
v
ROM
v
v
FIFO buffer
v
v
v
Simple dual-port mixed width support
v
v
v
v
v
True dual-port mixed width support
Memory initialization file (.mif)
Mixed-clock mode
v
v
v
v
v
Power-up condition
Outputs cleared
Outputs cleared
Outputs unknown
Register clears
Input and output
registers (1)
Input and output
registers (2)
Output registers
Same-port read-during-write
New data available at
positive clock edge
New data available at
positive clock edge
New data available at
positive clock edge
Mixed-port read-during-write
Outputs set to
unknown or old data
Outputs set to
unknown or old data
Unknown output
Notes to Table 2–1:
(1)
(2)
The rden register on the M512 memory block does not have a clear port.
On the M4K block, asserting the clear port of the rden and byte enable registers drives the output of these registers
high.
2–2
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
The extremely high memory bandwidth of the Stratix and Stratix GX
device families is a result of increased memory capacity and speed.
Table 2–2 shows the memory capacity for TriMatrix memory blocks in
each Stratix device. Table 2–3 shows the memory capacity for TriMatrix
memory blocks in each Stratix GX device.
Table 2–2. TriMatrix Memory Distribution in Stratix Devices
Device
M512
M4K
Columns/Blocks Columns/Blocks
EP1S10
4 / 94
EP1S20
EP1S25
M-RAM
Blocks
Total RAM Bits
2 / 60
1
920,448
6 / 194
2 / 82
2
1,669,248
6 / 224
3 / 138
2
1,944,576
EP1S30
7 / 295
3 / 171
4
3,317,184
EP1S40
8 / 384
3 / 183
4
3,423,744
EP1S60
10 / 574
4 / 292
6
5,215,104
EP1S80
11 / 767
4 / 364
9
7,427,520
Table 2–3. TriMatrix Memory Distribution in Stratix GX Devices
Device
M512
M4K
Columns/Blocks Columns/Blocks
M-RAM
Blocks
Total RAM Bits
EP1SGX10
4 / 94
2 / 60
1
920,448
EP1SGX25
6 / 224
3 / 138
2
1,944,576
EP1SGX40
8 / 384
3 / 183
4
3,423,744
Clear Signals
When applied to input registers, the asynchronous clear signal for the
TriMatrix embedded memory immediately clears the input registers.
However, the output of the memory block does not show the effects until
the next clock edge. When applied to output registers, the asynchronous
clear signal clears the output registers and the effects are seen
immediately.
Parity Bit Support
The memory blocks support a parity bit for each byte. Parity bits are in
addition to the amount of memory in each RAM block. For example, the
M512 block has 576 bits, 64 of which are optionally used for parity bit
Altera Corporation
July 2005
2–3
Stratix Device Handbook, Volume 2
TriMatrix Memory
storage. The parity bit, along with logic implemented in logic elements
(LEs), can implement parity checking for error detection to ensure data
integrity. Parity-size data words can also store user-specified control bits.
Byte Enable Support
In the M4K and M-RAM blocks, byte enables can mask the input data so
that only specific bytes of data are written. The unwritten bytes retain the
previous written value. The write enable signals (wren), in conjunction
with the byte enable signals (byteena), controls the RAM block’s write
operations. The default value for the byteena signals is high (enabled),
in which case writing is controlled only by the wren signals.
Asserting the clear port of the byte enable registers drives the byte enable
signals to their default high level.
M4K Blocks
M4K blocks support byte writes when the write port has a data width of
16, 18, 32, or 36 bits. Table 2–4 summarizes the byte selection.
Table 2–4. Byte Enable for M4K Blocks Notes (1), (2)
byteena
datain × 18
datain × 36
[0] = 1
[8..0]
[8..0]
[1] = 1
[17..9]
[17..9]
[2] = 1
–
[26..18]
[3] = 1
–
[35..27]
Notes to Table 2–4:
(1)
(2)
Any combination of byte enables is possible.
Byte enables can be used in the same manner with 8-bit words, i.e., in × 16 and × 32
modes.
2–4
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
M-RAM Blocks
M-RAM blocks support byte enables for the × 16, × 18, × 32, × 36, × 64, and
× 72 modes. In the × 128 or × 144 simple dual-port mode, the two sets of
byteena signals (byteena_a and byteena_b) combine to form the
necessary 16 byte enables. Tables 2–5 and 2–6 summarize the byte
selection.
Table 2–5. Byte Enable for M-RAM Blocks Notes (1), (2)
byteena
datain × 18
datain × 36
datain × 72
[0] = 1
[8..0]
[8..0]
[8..0]
[1] = 1
[17..9]
[17..9]
[17..9]
[2] = 1
–
[26..18]
[26..18]
[3] = 1
–
[35..27]
[35..27]
[4] = 1
–
–
[44..36]
[5] = 1
–
–
[53..45]
[6] = 1
–
–
[62..54]
[7] = 1
–
–
[71..63]
Notes to Table 2–5:
(1)
(2)
Any combination of byte enables is possible.
Byte enables can be used in the same manner with 8-bit words, that is, in × 16, × 32,
and × 64 modes.
Table 2–6. M-RAM Combined Byte Selection for × 144 Mode (Part 1 of 2),
Notes (1), (2)
byteena_a
Altera Corporation
July 2005
datain × 144
[0] = 1
[8..0]
[1] = 1
[17..9]
[2] = 1
[26..18]
[3] = 1
[35..27]
[4] = 1
[44..36]
[5] = 1
[53..45]
[6] = 1
[62..54]
[7] = 1
[71..63]
[8] = 1
[80..72]
[9] = 1
[89..81]
[10] = 1
[98..90]
[11] = 1
[107..99]
2–5
Stratix Device Handbook, Volume 2
TriMatrix Memory
Table 2–6. M-RAM Combined Byte Selection for × 144 Mode (Part 2 of 2),
Notes (1), (2)
byteena_a
datain × 144
[12] = 1
[116..108]
[13] = 1
[125..117]
[14] = 1
[134..126]
[15] = 1
[143..135]
Notes to Table 2–6:
(1)
(2)
Any combination of byte enables is possible.
Byte enables can be used in the same manner with 8-bit words, i.e., in × 16, × 32,
× 64, and × 128 modes.
Byte Enable Functional Waveform
Figure 2–1 shows how both the wren and the byteena signals control
the write operations of the RAM.
Figure 2–1. Byte Enable Functional Waveform Note (1)
inclock
wren
a0
address
an
data_in
XXXX
byteena
XX
contents at a0
contents at a1
a2
a0
a1
ABCD
10
a2
XXXX
01
11
FFFF
XX
ABFF
FFFF
FFCD
FFFF
contents at a2
asynch_data_out
a1
doutn
ABXX
ABCD
XXCD
ABCD
ABFF
FFCD
ABCD
Note to Figure 2–1:
(1)
For more information on simulation output when a read-during-write occurs at the same address location, see
“Read-During-Write Operation at the Same Address” on page 2–25.
2–6
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Using TriMatrix
Memory
f
The TriMatrix memory blocks include input registers that synchronize
writes and output registers to pipeline designs and improve system
performance. All TriMatrix memory blocks are pipelined, meaning that
all inputs are registered, but outputs are either registered or
combinatorial. TriMatrix memory can emulate a flow-through memory
by using combinatorial outputs.
For more information, see AN 210: Converting Memory from Asynchronous
to Synchronous for Stratix & Stratix GX Designs.
Depending on the TriMatrix memory block type, the memory can have
various modes, including:
■
■
■
■
■
■
Single-port
Simple dual-port
True dual-port (bidirectional dual-port)
Shift-register
ROM
FIFO
Implementing Single-Port Mode
Single-port mode supports non-simultaneous reads and writes.
Figure 2–2 shows the single-port memory configuration for TriMatrix
memory. All memory block types support the single-port mode.
Figure 2–2. Single-Port Memory Note (1)
data[ ]
address[ ]
wren
inclock
inclocken
inaclr
q[ ]
outclock
outclocken
outaclr
Note to Figure 2–2:
(1)
Two single-port memory blocks can be implemented in a single M4K block.
M4K memory blocks can also be divided in half and used for two
independent single-port RAM blocks. The Altera Quartus II software
automatically uses this single-port memory packing when running low
on memory resources. To force two single-port memories into one M4K
block, first ensure that each of the two independent RAM blocks is equal
to or less than half the size of the M4K block. Second, assign both singleport RAMs to the same M4K block.
Altera Corporation
July 2005
2–7
Stratix Device Handbook, Volume 2
Using TriMatrix Memory
In the single-port RAM configuration, the outputs can only be in
read-during-write mode, which means that during the write operation,
data written to the RAM flows through to the RAM outputs. When the
output registers are bypassed, the new data is available on the rising edge
of the same clock cycle it was written on. For more information about
read-during-write mode, see “Read-During-Write Operation at the Same
Address” on page 2–25.
Figure 2–3 shows timing waveforms for read and write operations in
single-port mode.
Figure 2–3. Single-Port Timing Waveforms
in clock
wren
address
an-1
an
data_in
din-1
din
synch_data_out
asynch_data_out
a0
din-2
din
din-1
din
din-1
a1
a2
dout0
dout0
dout1
a3
dout1
dout2
a4
a5
a6
din4
din5
din6
dout2
dout3
dout3
din4
din4
din5
Implementing Simple Dual-Port Mode
Simple dual-port memory supports a simultaneous read and write.
Figure 2–4 shows the simple dual-port memory configuration for
TriMatrix memory. All memory block types support this configuration.
Figure 2–4. Simple Dual-Port Memory Note (1)
Dual-Port Memory
data[ ]
wraddress[ ]
wren
inclock
inclocken
inaclr
rdaddress[ ]
rden
q[ ]
outclock
outclocken
outaclr
Note to Figure 2–4:
(1)
Simple dual-port RAM supports read/write clock mode in addition to the
input/output clock mode shown.
2–8
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
TriMatrix memory supports mixed-width configurations, allowing
different read and write port widths. When using mixed-width mode, the
LSB is written to or read from first. For example, take a RAM that is set up
in mixed-width mode with write data width ×8 and read data width ×2.
If a binary 00000001 is written to write dress 0, the following is read out
of the ×2 output side:
Read Address
×2 data
00
01(LSB of ×8 data)
01
00
10
00
11
00(MSB of ×8 data)
Tables 2–7 to 2–9 show the mixed width configurations for the M512,
M4K, and M-RAM blocks, respectively.
Table 2–7. M512 Block Mixed-Width Configurations (Simple Dual-Port Mode)
Write Port
Read Port
512 × 1
256 × 2
128 × 4
64 × 8
32 × 16
v
v
v
v
v
v
v
512 × 1
256 × 2
v
v
v
128 × 4
v
v
v
64 × 8
v
v
32 × 16
v
v
64 × 9
32 × 18
v
v
v
v
64 × 9
v
32 × 18
v
Table 2–8. M4K Block Mixed-Width Configurations (Simple Dual-Port Mode) (Part 1 of 2)
Write Port
Read Port
4K × 1 2K × 2 1K × 4 512 × 8 256 × 16
128 × 32 512 × 9 256 × 18
4K × 1
v
v
v
v
v
v
2K × 2
v
v
v
v
v
v
1K × 4
v
v
v
v
v
v
512 × 8
v
v
v
v
v
v
256 × 16
v
v
v
v
v
v
Altera Corporation
July 2005
128 × 36
2–9
Stratix Device Handbook, Volume 2
Using TriMatrix Memory
Table 2–8. M4K Block Mixed-Width Configurations (Simple Dual-Port Mode) (Part 2 of 2)
Write Port
Read Port
128 × 32
4K × 1 2K × 2 1K × 4 512 × 8 256 × 16
v
v
v
v
v
128 × 32 512 × 9 256 × 18
128 × 36
v
512 × 9
v
v
v
256 × 18
v
v
v
128 × 36
v
v
v
Table 2–9. M-RAM Block Mixed-Width Configurations (Simple Dual-Port Mode)
Write Port
Read Port
64K × 9
32K × 18
16K × 36
8K × 72
64K × 9
v
v
v
v
32K × 18
v
v
v
v
16K × 36
v
v
v
v
8K × 72
v
v
v
v
4K × 144
4K × 144
v
M512 blocks support serializer and deserializer (SERDES) applications.
By using the mixed-width support in combination with double data rate
(DDR) I/O standards, the block can function as a SERDES to support lowspeed serial I/O standards using global or regional clocks.
f
For more information on Stratix device I/O structure see the Stratix
Device Family Data Sheet section of the Stratix Device Handbook, Volume 1.
For more information on Stratix GX device I/O structure see the
Stratix GX Device Family Data Sheet section of the Stratix GX Device
Handbook, Volume 1.
In simple dual-port mode, the M512 and M4K blocks have one write
enable and one read enable signal. The M512 does not support a clear port
on the rden register. On the M4K block, asserting the clear port of the
rden register drives rden high, which allows the read operation to occur.
When the read enable is deactivated, the current data is retained at the
output ports. If the read enable is activated during a write operation with
the same address location selected, the simple dual-port RAM output is
either unknown or can be set to output the old data stored at the memory
address. For more information, see “Read-During-Write Operation at the
Same Address” on page 2–25.
2–10
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
M-RAM blocks have one write enable signal in simple dual-port mode. To
perform a write operation, the write enable is held high. The M-RAM
block is always enabled for read operation. If the read address and the
write address select the same address location during a write operation,
the M-RAM block output is unknown.
Figure 2–5 shows timing waveforms for read and write operations in
simple dual-port mode.
Figure 2–5. Simple Dual-Port Timing Waveforms Note (1)
wrclock
wren
wraddress
an-1
an
data_in
din-1
din
a0
a1
a2
a3
a4
a5
a6
din4
din5
din6
rdclock
rden
rdaddress
synch_data_out
asynch_data_out
bn
doutn-2
doutn-1
b1
b0
doutn-1
doutn
b2
doutn
b3
dout0
dout0
Note to Figure 2–5:
(1)
The rden signal is not available in the M-RAM block. A M-RAM block in simple dual-port mode is always reading
out the data stored at the current read address location.
Implementing True Dual-Port Mode
M4K and M-RAM blocks offer a true dual-port mode to support any
combination of two-port operations: two reads, two writes, or one read
and one write at two different clock frequencies. Figure 2–6 shows the
true dual-port memory configuration for TriMatrix memory.
Altera Corporation
July 2005
2–11
Stratix Device Handbook, Volume 2
Using TriMatrix Memory
Figure 2–6. True Dual-Port Memory Note (1)
A
B
dataA[ ]
addressA[ ]
wrenA
clockA
clockenA
qA[ ]
aclrA
dataB[ ]
addressB[ ]
wrenB
clockB
clockenB
qB[ ]
aclrB
Note to Figure 2–6:
(1)
True dual-port memory supports input/output clock mode in addition to the
independent clock mode shown.
The widest bit configuration of the M4K and M-RAM blocks in true dualport mode is 256 × 16-bit (× 18-bit with parity) and 8K × 64-bit (× 72-bit
with parity), respectively. The 128 × 32-bit (× 36-bit with parity)
configuration of the M4K block and the 4K × 128-bit (× 144-bit with parity)
configuration of the M-RAM block are unavailable because the number of
output drivers is equivalent to the maximum bit width of the respective
memory block. Because true dual-port RAM has outputs on two ports,
the maximum width of the true dual-port RAM equals half of the total
number of output drivers. Tables 2–10 and 2–11 list the possible M4K
RAM block and M-RAM block configurations, respectively.
Table 2–10. M4K Block Mixed-Port Width Configurations (True Dual-Port)
Port B
Port A
4K × 1
2K × 2
1K × 4
512 × 8
256 × 16
512 × 9
256 × 18
4K × 1
v
v
v
v
v
2K × 2
v
v
v
v
v
1K × 4
v
v
v
v
v
512 × 8
v
v
v
v
v
256 × 16
v
v
v
v
v
512 × 9
v
v
256 × 18
v
v
2–12
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Table 2–11. M-RAM Block Mixed-Port Width Configurations (True Dual-Port)
Port B
Port A
64K × 9
32K × 18
16K × 36
8K × 72
64K × 9
v
v
v
v
32K × 18
v
v
v
v
16K × 36
v
v
v
v
8K × 72
v
v
v
v
In true dual-port configuration, the RAM outputs can only be configured
for read-during-write mode. This means that during write operation,
data being written to the A or B port of the RAM flows through to the A
or B outputs, respectively. When the output registers are bypassed, the
new data is available on the rising edge of the same clock cycle it was
written on. For waveforms and information on mixed-port read-duringwrite mode, see “Read-During-Write Operation at the Same Address” on
page 2–25.
Potential write contentions must be resolved external to the RAM because
writing to the same address location at both ports results in unknown
data storage at that location. Data is written on the rising edge of the write
clock for the M-RAM block. For a valid write operation to the same
address of the M-RAM block, the rising edge of the write clock for port A
must occur following the maximum write cycle time interval after the
rising edge of the write clock for port B. Since data is written into the
M512 and M4K blocks at the falling edge of the write clock, the rising
edge of the write clock for port A should occur following half of the
maximum write cycle time interval after the falling edge of the write clock
for port B. If this timing is not met, the data stored in that particular
address is invalid.
f
See the Stratix Device Family Data Sheet section of the Stratix Device
Handbook, Volume 1 or the Stratix GX Device Family Data Sheet section of
the Stratix GX Device Handbook, Volume 1 for the maximum synchronous
write cycle time.
Figure 2–7 shows true dual-port timing waveforms for write operation at
port A and read operation at port B.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Using TriMatrix Memory
Figure 2–7. True Dual-Port Timing Waveforms
A_clk
A_wren
A_address
A_data_in
an-1
an
din-1
din
A_synch_data_out
din-2
A_asynch_data_out
a0
din
din-1
din
din-1
a1
a2
dout0
dout1
dout1
dout0
a3
a4
a5
a6
din4
din5
din6
dout2
dout2
din4
dout3
dout3
din5
din4
B_clk
B_wren
B_address
B_synch_data_out
B_asynch_data_out
bn
doutn-2
doutn-1
b1
b0
doutn-1
doutn
b2
dout0
doutn
dout0
b3
dout1
dout2
dout1
Implementing Shift-Register Mode
Embedded memory block configurations can implement shift registers
for digital signal processing (DSP) applications, such as finite impulse
response (FIR) filters, pseudo-random number generators, multi-channel
filtering, and auto-correlation and cross-correlation functions. These and
other DSP applications require local data storage, traditionally
implemented with standard flip-flops that can quickly consume many
logic cells for large shift registers. A more efficient alternative is to use
embedded memory as a shift register block, which saves logic cell and
routing resources and provides a more efficient implementation.
The size of a (w × m × n) shift register is determined by the input data
width (w), the length of the taps (m), and the number of taps (n). The size
of a (w × m × n) shift register must be less than or equal to the maximum
number of memory bits in the respective block: 576 bits for the M512
block and 4,608 bits for the M4K block. In addition, the size of w × n must
be less than or equal to the maximum width of the respective block: 18
bits for the M512 block and 36 bits for the M4K block. If a larger shift
register is required, the memory blocks can be cascaded together.
1
2–14
Stratix Device Handbook, Volume 2
M-RAM blocks do not support the shift-register mode.
Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Data is written into each address location at the falling edge of the clock
and read from the address at the rising edge of the clock. The shift-register
mode logic automatically controls the positive and negative edge
clocking to shift the data in one clock cycle. Figure 2–8 shows the
TriMatrix memory block in the shift-register mode.
Figure 2–8. Shift-Register Memory Configuration
w × m × n Shift Register
m-Bit Shift Register
w
w
m-Bit Shift Register
w
w
n Number
of Taps
m-Bit Shift Register
w
w
m-Bit Shift Register
w
w
Implementing ROM Mode
The M512 and the M4K blocks support ROM mode. Use a memory
initialization file (.mif) to initialize the ROM contents of M512 and M4K
blocks. The M-RAM block does not support ROM mode.
All Stratix memory configurations must have synchronous inputs;
therefore, the address lines of the ROM are registered. The outputs can be
registered or combinatorial. The ROM read operation is identical to the
read operation in the single-port RAM configuration.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Clock Modes
Implementing FIFO Buffers
While the small M512 memory blocks are ideal for designs with many
shallow FIFO buffers, all three memory sizes support FIFO mode.
All memory configurations have synchronous inputs; however, the FIFO
buffer outputs are always combinatorial. Simultaneous read and write
from an empty FIFO is not supported.
Clock Modes
Depending on the TriMatrix memory mode, independent, input/output,
read/write, and/or single-port clock modes are available. Table 2–12
shows the clock modes supported by the TriMatrix memory modes.
Table 2–12. TriMatrix Memory Clock Modes
Clocking Mode
True-Dual Port
Mode
Independent
v
Input/output
v
Read/write
Single-port
Simple DualPort Mode
Single-Port
Mode
v
v
v
Independent Clock Mode
The TriMatrix memory blocks can implement independent clock mode
for true dual-port memory. In this mode, a separate clock is available for
each port (A and B). Clock A controls all registers on the port A side,
while clock B controls all registers on the port B side. Each port also
supports independent clock enables and asynchronous clear signals for
port A and B registers. Figure 2–9 shows a TriMatrix memory block in
independent clock mode.
2–16
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
clockB
clkenB
wrenB
addressB[ ]
D
ENA
D
D
Q
ENA
ENA
Q
Q
ENA
D
Q
ENA
ENA
D
clockA
clkenA
wrenA
addressA[ ]
byteenaA[ ]
dataA[ ]
8
D
8 LAB Row Clocks
Q
Write
Pulse
Generator
D
Data Out
Address A
Write/Read
Enable
qA[ ]
qB[ ]
Q
Data Out
Write/Read
Enable
Address B
Byte Enable B
Byte Enable A
B
Data In
Memory Block
256 ´ 16 (2)
512 ´ 8
1,024 ´ 4
2,048 ´ 2
4,096 ´ 1
A
Data In
ENA
Write
Pulse
Generator
Q
D
ENA
Q
D
ENA
Q
D
Q
ENA
8
dataB[ ]
byteenaB[ ]
Figure 2–9. Independent Clock Mode Note (1), (2)
Note to Figure 2–9:
(1)
(2)
Violating the setup or hold time on the address registers could corrupt the memory contents. This applies to both
read and write operations.
All registers shown have asynchronous clear ports, except when using the M-RAM. M-RAM blocks have
asynchronous clear ports on their output registers only.
Altera Corporation
July 2005
2–17
Stratix Device Handbook, Volume 2
Clock Modes
Input/Output Clock Mode
The TriMatrix memory blocks can implement input/output clock mode
for true and simple dual-port memory. On each of the two ports, A and B,
one clock controls all registers for inputs into the memory block: data
input, wren, and address. The other clock controls the block’s data output
registers. Each memory block port also supports independent clock
enables and asynchronous clear signals for input and output registers.
Figures 2–10 and 2–11 show the memory block in input/output clock
mode for true and simple dual-port modes, respectively.
2–18
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
(1)
Altera Corporation
July 2005
clockA
clkenA
wrenA
addressA[ ]
byteenaA[ ]
dataA[ ]
8
ENA
D
ENA
D
ENA
D
ENA
D
8 LAB Row Clocks
Q
Q
Q
Q
Write
Pulse
Generator
Q
Data Out
Write/Read
Enable
Address A
ENA
D
A
qA[ ]
Data In
B
qB[ ]
Q
D
ENA
Data Out
Write/Read
Enable
Address B
Byte Enable B
Memory Block
256 × 16 (2)
512 × 8
1,024 × 4
2,048 × 2
4,096 × 1
Byte Enable A
Data In
Write
Pulse
Generator
Q
Q
Q
Q
ENA
D
ENA
D
ENA
D
ENA
D
8
clockB
clkenB
wrenB
addressB[ ]
byteenaB[ ]
dataB[ ]
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Figure 2–10. Input/Output Clock Mode in True Dual-Port Mode Note (1)
Note to Figure 2–10:
Violating the setup or hold time on the address registers could corrupt the memory contents. This applies to both
read and write operations.
2–19
Stratix Device Handbook, Volume 2
Clock Modes
All registers shown have asynchronous clear ports, except when using
the M-RAM. M-RAM blocks have asynchronous clear ports on their
output registers only.
Figure 2–11. Input/Output Clock Mode in Simple Dual-Port Mode Notes (1), (2), (3), (4)
8 LAB Row
Clocks
Memory Block
256 ´ 16
512 ´ 8
1,024 ´ 4
2,048 ´ 2
4,096 ´ 1
8
data[ ]
D
Q
ENA
Data In
address[ ]
D
Q
ENA
Read Address
Data Out
byteena[ ]
D
Q
ENA
Byte Enable
wraddress[ ]
D
Q
ENA
Write Address
D
Q
ENA
Read Enable
D
Q
ENA
To MultiTrack
Interconnect
rden
wren
outclken
inclken
wrclock
D
Q
ENA
Write
Pulse
Generator
Write Enable
rdclock
Notes to Figure 2–11:
(1)
(2)
(3)
(4)
The rden signal is not available in the M-RAM block. A M-RAM block in simple dual-port mode is always reading
out the data stored at the current read address location.
For more information on the MultiTrack™ interconnect, see the Stratix Device Family Data Sheet section of the Stratix
Device Handbook, Volume 1 or the Stratix GX Device Family Data Sheet section of the Stratix GX Device Handbook,
Volume 1.
All registers shown have asynchronous clear ports, except when using the M-RAM. M-RAM blocks have
asynchronous clear ports on their output registers only.
Violating the setup or hold time on the address registers could corrupt the memory contents. This applies to both
read and write operations.
2–20
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Read/Write Clock Mode
The TriMatrix memory blocks can implement read/write clock mode for
simple dual-port memory. This mode can use up to two clocks. The write
clock controls the block’s data inputs, wraddress, and wren. The read
clock controls the data output, rdaddress, and rden. The memory
blocks support independent clock enables for each clock and
asynchronous clear signals for the read- and write-side registers.
Figure 2–12 shows a memory block in read/write clock mode.
Altera Corporation
July 2005
2–21
Stratix Device Handbook, Volume 2
Clock Modes
Figure 2–12. Read/Write Clock Mode in Simple Dual-Port Mode Notes (1), (2), (3)
8 LAB Row
Clocks
Memory Block
256 × 16
512 × 8
1,024 × 4
Data In
2,048 × 2
4,096 × 1
8
data[ ]
D
Q
ENA
Data Out
address[ ]
D
Q
ENA
Read Address
wraddress[ ]
D
Q
ENA
Write Address
byteena[ ]
D
Q
ENA
Byte Enable
D
Q
ENA
To MultiTrack
Interconnect
rden
D
Q
ENA
wren
Read
Pulse
Generator
Read Enable
rdclocken
wrclocken
wrclock
D
Q
ENA
Write
Pulse
Generator
Write Enable
rdclock
Notes to Figure 2–12:
(1)
(2)
(3)
For more information on the MultiTrack interconnect, see the Stratix Device Family Data Sheet section of the Stratix
Device Handbook, Volume 1 or the Stratix GX Device Family Data Sheet section of the Stratix GX Device Handbook,
Volume 1.
All registers shown have asynchronous clear ports, except when using the M-RAM. M-RAM blocks have
asynchronous clear ports on their output registers only.
Violating the setup or hold time on the address registers could corrupt the memory contents. This applies to both
read and write operations.
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Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Single-Port Mode
The TriMatrix memory blocks can implement single-port clock mode for
single-port memory mode. Single-port mode is used when simultaneous
reads and writes are not required. See Figure 2–13. A single block in a
memory block can support up to two single-port mode RAM blocks in
M4K blocks.
Figure 2–13. Single-Port Mode Notes (1), (2), (3)
8 LAB Row
Clocks
RAM/ROM
256 × 16
512 × 8
1,024 × 4
Data In
2,048 × 2
4,096 × 1
8
data[ ]
D
Q
ENA
Data Out
address[ ]
D
Q
ENA
Address
D
Q
ENA
To MultiTrack
Interconnect
wren
Write Enable
outclken
inclken
inclock
D
Q
ENA
Write
Pulse
Generator
outclock
Notes to Figure 2–13:
(1)
(2)
(3)
For more information on the MultiTrack interconnect, see the Stratix Device Family Data Sheet section of the Stratix
Device Handbook, Volume 1 or the Stratix GX Device Family Data Sheet section of the Stratix GX Device Handbook,
Volume 1.
All registers shown have asynchronous clear ports, except when using the M-RAM. M-RAM blocks have
asynchronous clear ports on their output registers only.
Violating the setup or hold time on the address registers could corrupt the memory contents. This applies to both
read and write operations.
Designing With
TriMatrix
Memory
Altera Corporation
July 2005
When instantiating TriMatrix memory you must understand the various
features that set it apart from other memory architectures. The following
sections describe some of the important attributes and functionality of
TriMatrix memory.
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Stratix Device Handbook, Volume 2
Designing With TriMatrix Memory
f
For information on the difference between APEX-style memory and
TriMatrix memory, see the Transitioning APEX Designs to Stratix Devices
chapter.
Selecting TriMatrix Memory Blocks
The Quartus II software automatically partitions user-defined memory
into embedded memory blocks using the most efficient size
combinations. The memory can also be manually assigned to a specific
block size or a mixture of block sizes. Table 2–1 on page 2–2 is a guide for
selecting a TriMatrix memory block size based on supported features.
1
f
Violating the setup or hold time on the address registers could
corrupt the memory contents. This applies to both read and
write operations.
For more information on selecting which memory block to use, see
AN 207: TriMatrix Memory Selection Using the Quartus II Software.
1
Violating the setup or hold time on the address registers could
corrupt the memory contents. This applies to both read and
write operations.
Pipeline & Flow-Through Modes
TriMatrix memory architecture implements synchronous (pipelined)
RAM by registering both the input and output signals to the RAM block.
All TriMatrix memory inputs are registered providing synchronous write
cycles. In synchronous operation, RAM generates its own self-timed
strobe write enable (wren) signal derived from the global or regional
clock. In contrast, a circuit using asynchronous RAM must generate the
RAM wren signal while ensuring its data and address signals meet setup
and hold time specifications relative to the wren signal. The output
registers can be bypassed.
In an asynchronous memory neither the input nor the output is
registered. While Stratix and Stratix GX devices do not support
asynchronous memory, they do support a flow-through read where the
output data is available during the clock cycle when the read address is
driven into it. Flow-through reading is possible in the simple and true
dual-port modes of the M512 and M4K blocks by clocking the read enable
and read address registers on the negative clock edge and bypassing the
output registers.
f
For more information, see AN 210: Converting Memory from Asynchronous
to Synchronous for Stratix & Stratix GX Devices.
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Altera Corporation
July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Power-up Conditions & Memory Initialization
Upon power-up, TriMatrix memory is in an idle state. The M512 and M4K
block outputs always power-up to zero, regardless of whether the output
registers are used or bypassed. Even if a memory initialization file is used
to pre-load the contents of the RAM block, the outputs still power-up
cleared. For example, if address 0 is pre-initialized to FF, the M512 and
M4K blocks power-up with the output at 00.
M-RAM blocks do not support memory initialization files; therefore, they
cannot be pre-loaded with data upon power-up. M-RAM blocks
combinatorial outputs and memory controls always power-up to an
unknown state. If M-RAM block outputs are registered, the registers
power-up cleared. The undefined output appears one clock cycle later.
The output remains undefined until a read operation is performed on an
address that has been written to.
Read-DuringWrite Operation
at the Same
Address
The following two sections describe the functionality of the various RAM
configurations when reading from an address during a write operation at
that same address. There are two types of read-during-write operations:
same-port and mixed-port. Figure 2–14 illustrates the difference in data
flow between same-port and mixed-port read-during-write.
Figure 2–14. Read-During-Write Data Flow
Port A
data in
Port B
data in
Mixed-port
data flow
Same-port
data flow
Port A
data out
Port B
data out
Same-Port Read-During-Write Mode
For read-during-write operation of a single-port RAM or the same port of
a true dual-port RAM, the new data is available on the rising edge of the
same clock cycle it was written on. This behavior is valid on all memoryblock sizes. See Figure 2–15 for a sample functional waveform.
Altera Corporation
July 2005
2–25
Stratix Device Handbook, Volume 2
Read-During-Write Operation at the Same Address
When using byte enables in true dual-port RAM mode, the outputs for
the masked bytes on the same port are unknown. (See Figure 2–1 on
page 2–6.) The non-masked bytes are read out as shown in Figure 2–15.
Figure 2–15. Same-Port Read-During-Write Functionality Note (1)
inclock
data_in
A
B
wren
data_out Old
A
Note to Figure 2–15:
(1)
Outputs are not registered.
Mixed-Port Read-During-Write Mode
This mode is used when a RAM in simple or true dual-port mode has one
port reading and the other port writing to the same address location with
the same clock.
The READ_DURING_WRITE_MODE_MIXED_PORTS parameter for M512
and M4K memory blocks determines whether to output the old data at
the address or a “don’t care” value. Setting this parameter to OLD_DATA
outputs the old data at that address. Setting this parameter to DONT_CARE
outputs a “don’t care” or unknown value. See Figures 2–16 and 2–17 for
sample functional waveforms showing this operation. These figures
assume that the outputs are not registered.
The DONT_CARE setting allows memory implementation in any TriMatrix
memory block. The OLD_DATA setting restricts memory implementation
to only M512 or M4K memory blocks. Selecting DONT_CARE gives the
compiler more flexibility when placing memory functions into TriMatrix
memory.
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July 2005
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
Figure 2–16. Mixed-Port Read-During-Write: OLD_DATA
inclock
addressA and
addressB
Port A
data_in
Address Q
A
B
Port A
wren
Port B
wren
Port B
data_out
Old
A
B
For mixed-port read-during-write operation of the same address location
of a M-RAM block, the RAM outputs are unknown, as shown in
Figure 2–17.
Figure 2–17. Mixed-Port Read-During-Write: DONT_CARE
inclock
addressA and
addressB
Port A
data_in
Address Q
A
B
Port A
wren
Port B
wren
Port B
data_out
Unknown
B
Mixed-port read-during-write is not supported when two different clocks
are used in a dual-port RAM. The output value will be unknown during
a mixed-port read-during-write operation.
Conclusion
Altera Corporation
July 2005
TriMatrix memory, an enhanced RAM architecture with extremely high
memory bandwidth in Stratix and Stratix GX devices, gives advanced
control of memory applications with features such as byte enables, parity
bit storage, and shift-register mode, as well as mixed-port width support
and true dual-port mode.
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Conclusion
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Altera Corporation
July 2005
3. External Memory
Interfaces in Stratix &
Stratix GX Devices
S52008-3.3
Introduction
Stratix® and Stratix GX devices support a broad range of external
memory interfaces such as double data rate (DDR) SDRAM, RLDRAM II,
quad data rate (QDR) SRAM, QDRII SRAM, zero bus turnaround (ZBT)
SRAM, and single data rate (SDR) SDRAM. The dedicated phase-shift
circuitry allows the Stratix and Stratix GX devices to interface at twice the
system clock speed with an external memory (up to 200 MHz/400 Mbps).
Typical I/O architectures transmit a single data word on each positive
clock edge and are limited to the associated clock speed using this
protocol. To achieve a 400-megabits per second (Mbps) transfer rate, a
SDR system requires a 400-MHz clock. Many new applications have
introduced a DDR I/O architecture as an alternative to SDR architectures.
While SDR architectures capture data on one edge of a clock, the DDR
architectures captures data on both the rising and falling edges of the
clock, doubling the throughput for a given clock frequency and
accelerating performance. For example, a 200-MHz clock can capture a
400-Mbps data stream, enhancing system performance and simplifying
board design.
Most current memory architectures use a DDR I/O interface. These DDR
memory standards cover a broad range of applications for embedded
processor systems, image processing, storage, communications, and
networking. This chapter describes the hardware features in Stratix and
Stratix GX devices that facilitate the high-speed memory interfacing for
each memory standard. It then briefly explains how each memory
standard uses the features of the Stratix and Stratix GX devices.
f
External
Memory
Standards
You can use this document with AN 329: ZBT SRAM Controller Reference
Design for Stratix & Stratix GX Devices, AN 342: Interfacing DDR SDRAM
with Stratix & Stratix GX Devices, and AN 349: QDR SRAM Controller
Reference Design for Stratix & Stratix GX Devices.
The following sections provide an overview on using the Stratix and
Stratix GX device external memory interfacing features.
DDR SDRAM
DDR SDRAM is a memory architecture that transmits and receives data
at twice the clock speed of traditional SDR architectures. These devices
transfer data on both the rising and falling edge of the clock signal.
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June 2006
3–1
External Memory Standards
Interface Pins
DDR devices use interface pins including data, data strobe, clock,
command, and address pins. Data is sent and captured at twice the clock
rate by transferring data on both the positive and negative edge of a clock.
The commands and addresses only use one active edge of a clock.
Connect the memory device’s DQ and DQS pins to the DQ and DQS pins,
respectively, as listed in the Stratix and Stratix GX devices pin table. DDR
SDRAM also uses active-high data mask pins for writes. You can connect
DM pins to any of the I/O pins in the same bank as the DQ pins of the
FPGA. There is one DM pin per DQS/DQ group.
DDR SDRAM ×16 devices use two DQS pins, and each DQS pin is
associated with eight DQ pins. However, this is not the same as the
×16 mode in Stratix and Stratix GX devices. To support a ×16 DDR
SDRAM, you need to configure the Stratix and Stratix GX FPGAs to use
two sets of DQ pins in ×8 mode. Similarly if your ×32 memory device uses
four DQS pins where each DQS pin is associated with eight DQ pins, you
need to configure the Stratix and Stratix GX FPGA to use four sets of pins
in ×8 mode.
You can also use any I/O pins in banks 1, 2, 5, or 6 to interface with
DDR SDRAM devices. These banks do not have dedicated circuitry,
though.
You can also use any of the user I/O pins for commands and addresses to
the DDR SDRAM.
f
For more information, see AN 342: Interfacing DDR SDRAM with Stratix
& Stratix GX Devices.
If the DDR SDRAM device supports ECC, the design uses a DQS/DQ
group for ECC pins. You can use any of the user I/O pins for commands
and addresses.
Because of the symmetrical setup and hold time for the command and
address pins at the memory, you might need to generate these signals
from the system clock’s negative edge.
The clocks to the SDRAM device are called CK and CK#. Use any of the
user I/O pins via the DDR registers to generate the CK and CK# signals
to meet the DDR SDRAM tDQSS requirement. The memory device’s tDQSS
requires that the DQS signal’s positive edge write operations must be
within 25% of the positive edge of the DDR SDRAM clock input. Using
user I/O pins for CK and CK# ensures that any PVT variations seen by
the DQS signal are tracked by these pins, too.
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June 2006
External Memory Interfaces in Stratix & Stratix GX Devices
Read & Write Operations
When reading from the DDR SDRAM, the DQS signal coming into the
Stratix and Stratix GX device is edge-aligned with the DQ pins. The
dedicated circuitry center-aligns the DQS signal with respect to the DQ
signals and the shifted DQS bus drives the clock input of the DDR input
registers. The DDR input registers bring the data from the DQ signals to
the device. The system clock clocks the DQS output enable and output
paths. The -90° shifted clock clocks the DQ output enable and output
paths. Figure 3–1 shows an example of the DQ and DQS relationship
during a burst-of-two read. It shows where the DQS signal is
center-aligned in the IOE.
Figure 3–1. Example of Where a DQS Signal is Center-Aligned in the IOE
Pin to register
delay
DQS at
FPGA Pin
Postamble
Preamble
DQ at
FPGA Pin
DQS at DQ
IOE registers
DQ at DQ
IOE registers
90 degree shift
Pin to register
delay
When writing to the DDR SDRAM, the DQS signal must be centeraligned with the DQ pins. Two PLL outputs are needed to generate the
DQS signal and to clock the DQ pins. The DQS are clocked by the 0°
phase-shift PLL output, while the DQ pins are clocked by the -90° phaseshifted PLL output. Figure 3–2 shows the DQS and DQ relationship
during a DDR SDRAM burst-of-two write.
Figure 3–2. DQ & DQS Relationship During a Burst-of-Two Write
DQS at
FPGA Pin
DQ at
FPGA Pin
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June 2006
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Stratix Device Handbook, Volume 2
External Memory Standards
Figure 3–3 shows DDR SDRAM interfacing from the I/O through the
dedicated circuitry to the logic array. When the DQS pin acts as an input
strobe, the dedicated circuitry shifts the incoming DQS pin by either 72°
or 90° and clocks the DDR input registers. Because of the DDR input
registers architecture in Stratix and Stratix GX devices, the shifted DQS
signal must be inverted. The DDR registers outputs are sent to two LE
registers to be synchronized with the system clock.
f
Refer to the DC & Switching Characteristics chapter in volume 1 of the
Stratix Device Handbook for frequency limits regarding the 72 and 90°
phase shift for DQS.
Figure 3–3. DDR SDRAM Interfacing
DQ
DQS
Compensated
Delay Shift
OE
PLL
DDR
OE
Registers
User logic/ 2
GND
2
DDR
Output
Registers
OE
Δt
DDR
OE
Registers
2
DDR
Output
Registers
DDR
Input
Registers
I/O Elements &
Periphery
− 90˚
DQS Bus
LE
Register
LE
Register
Resynchronizing
Global Clock
f
Adjacent LAB LEs
For more information on DDR SDRAM specifications, see JEDEC
standard publications JESD79C from www.jedec.org, or see
AN 342: Interfacing DDR SDRAM with Stratix & Stratix GX Devices.
RLDRAM II
RLDRAM II provides fast random access as well as high bandwidth and
high density, making this memory technology ideal for high-speed
network and communication data storage applications. The fast random
access speeds in RLDRAM II devices make them a viable alternative to
SRAM devices at a lower cost. Additionally, RLDRAM II devices have
minimal latency to support designs that require fast response times.
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External Memory Interfaces in Stratix & Stratix GX Devices
Interface Pins
RLDRAM II devices use interface pins such as data, clock, command, and
address pins. There are two types of RLDRAM II memory: common I/O
(CIO) and separate I/O (SIO). The data pins in RLDRAM II CIO device
are bidirectional while the data pins in a RLDRAM II SIO device are
uni-directional. Instead of bidirectional data strobes, RLDRAM II uses
differential free-running read and write clocks to accompany the data. As
in DDR SDRAM, data is sent and captured at twice the clock rate by
transferring data on both the positive and negative edge of a clock. The
commands and addresses still only use one active edge of a clock.
If the data pins are bidirectional, connect them to the Stratix and
Stratix GX device DQ pins. If the data pins are uni-directional, connect
the RLDRAM II device Q ports to the Stratix and Stratix GX device DQ
pins and connect the D ports to any user I/O pins in I/O banks 3, 4, 7, and
8. RLDRAM II also uses active-high data mask pins for writes. You can
connect DM pins to any of the I/O pins in the same bank as the DQ pins
of the FPGA. When interfacing with SIO devices, connect the DM pins to
any of the I/O pins in the same bank as the D pins. There is one DM pin
per DQS/DQ group.
Connect the read clock pins (QK) to Stratix and Stratix GX device DQS
pins. You must configure the DQS signals as bidirectional pins. However,
since QK pins are output-only pins from the memory, RLDRAM memory
interfacing in Stratix and Stratix GX devices requires that you ground the
DQS and DQSn pin output enables. The Stratix and Stratix GX devices
use the shifted QK signal from the DQS logic block to capture data. You
can leave the QK# signal of the RLDRAM II device unconnected.
RLDRAM II devices have both input clocks (CK and CK#) and write
clocks (DK and DK#). Use the external clock buffer to generate CK, CK#,
DK, and DK# to meet the CK, CK#, DK, and DK# skew requirements from
the RLDRAM II device. If you are interfacing with multiple RLDRAM II
devices, perform IBIS simulations to analyze the loading effects on the
clock pair.
You can use any of the user I/O pins for commands and addresses.
RLDRAM II also offers QVLD pins to indicate the read data availability.
Connect the QVLD pins to the Stratix and Stratix GX device DQVLD pins,
listed in the pin table.
Read & Write Operations
When reading from the RLDRAM II device, data is sent edge-aligned
with the read clock QK or QK# signal. When writing to the RLDRAM II
device, data must be center-aligned with the write clock (DK or DK#
signal). The Stratix and Stratix GX device RLDRAM II interface uses the
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June 2006
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Stratix Device Handbook, Volume 2
External Memory Standards
same scheme as in DDR SDRAM interfaces whereby the dedicated
circuitry is used during reads to center-align the data and the read clock
inside the FPGA and the PLL center-aligns the data and write clock
outputs. The data and clock relationship for reads and writes in
RLDRAM II is similar to those in DDR SDRAM as already depicted in
Figure 3–1 on page 3–3 and Figure 3–3 on page 3–4.
QDR & QDRII SRAM
QDR SRAM provides independent read and write ports that eliminate
the need for bus turnaround. The memory uses two sets of clocks: K and
Kn for write access, and optional C and Cn for read accesses, where Kn
and Cn are the inverse of the K and C clocks, respectively. You can use
differential HSTL I/O pins to drive the QDR SRAM clock into the Stratix
and Stratix GX devices. The separate write data and read data ports
permit a transfer rate up to four words on every cycle through the DDR
circuitry. Stratix and Stratix GX devices support both burst-of-two and
burst-of-four QDR SRAM architectures, with clock cycles up to 167 MHz
using the 1.5-V HSTL Class I or Class II I/O standard. Figure 3–4 shows
the block diagram for QDR SRAM burst-of-two architecture.
Figure 3–4. QDR SRAM Block Diagram for Burst-of-Two Architecture
Discrete QDR SRAM Device
A
18
BWSn
Write
Port
WPSn
D
36
Data
256K × 18
Memory
Array
256K × 18
Memory 36
Array
Data
Read
Port
RPSn
2
C, Cn
18
Q
18
2
K, Kn
VREF
Control
Logic
QDRII SRAM is a second generation of QDR SRAM devices. It can
transfer four words per clock cycle, fulfilling the requirements facing
next-generation communications system designers. QDRII SRAM
devices provide concurrent reads and writes, zero latency, and increased
data throughput. Stratix and Stratix GX devices support QDRII SRAM at
speeds up to 200 MHz since the timing requirements for QDRII SRAM
are not as strict as QDR SRAM.
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External Memory Interfaces in Stratix & Stratix GX Devices
Interface Pins
QDR and QDRII SRAM uses two separate, uni-directional data ports for
read and write operations, enabling quad data-rate data transfer. Both
QDR and QDRII SRAM use shared address lines for reads and writes.
Stratix and Stratix GX devices utilize dedicated DDR I/O circuitry for the
input and output data bus and the K and Kn output clock signals.
Both QDR and QDRII SRAM burst-of-two devices sample the read
address on the rising edge of the K clock and sample the write address on
the rising edge of the Kn clock while QDR and QDRII SRAM burst-offour devices sample both read and write addresses on the K clock's rising
edge. You can use any of the Stratix and Stratix GX device user I/O pins
in I/O banks 3, 4, 7, and 8 for the D write data ports, commands, and
addresses.
QDR SRAM uses the following clock signals: input clocks K and Kn and
output clocks C and Cn. In addition to the aforementioned two pairs of
clocks, QDRII SRAM also uses echo clocks CQ and CQn. Clocks Cn, Kn,
and CQn are logical complements of clocks C, K, and CQ respectively.
Clocks C, Cn, K, and Kn are inputs to the QDRII SRAM while clocks CQ
and CQn are outputs from the QDRII SRAM. Stratix and Stratix GX
devices use single-clock mode for single-device QDR and QDRII SRAM
interfacing where the K and Kn are used for both read and write
operations, and the C and Cn clocks are unused. Use both C or Cn and K
or Kn clocks when interfacing with a bank of multiple QDRII SRAM
devices with a single controller.
You can generate C, Cn, K, and Kn clocks using any of the I/O registers
in I/O banks 3, 4, 7, or 8 via the DDR registers. Due to strict skew
requirements between K and Kn signals, use adjacent pins to generate the
clock pair. Surround the pair with buffer pins tied to VCC and ground for
better noise immunity from other signals.
In general, all output signals to the QDR and QDRII SRAM should use the
top and bottom banks (I/O banks 3, 4, 7, or 8). You can place the input
signals from the QDR and QDRII SRAM in any I/O banks.
Read & Write Operations
Figure 3–5 shows the data and clock relationships in QDRII SRAM
devices at the memory pins during reads. QDR and QDRII SRAM devices
send data within a tCO time after each rising edge of the input clock C or
Cn in multi-clock mode, or the input clock K or Kn in single clock mode.
Data is valid until tDOH time, after each rising edge of the C or Cn in multi-
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June 2006
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External Memory Standards
clock mode, or K or Kn in single clock mode. The edge-aligned CQ and
CQn clocks accompany the read data for data capture in Stratix and
Stratix GX devices.
Figure 3–5. Data & Clock Relationship During a QDRII SRAM Read
Note (1)
C/K
Cn/Kn
tCO (2)
Q
tCO (2)
QA
tCLZ (3)
QA + 1
tDOH (2)
QA + 2
QA + 3
tCHZ (3)
CQ
tCQD (4)
CQn
tCCQO (5)
tCQOH (5)
tCQD (4)
Notes to Figure 3–5:
(1)
(2)
(3)
(4)
(5)
The timing parameter nomenclature is based on the Cypress QDRII SRAM data sheet for CY7C1313V18.
CO is the data clock-to-out time and tDOH is the data output hold time between burst.
tCLZ and tCHZ are bus turn-on and turn-off times respectively.
tCQD is the skew between CQn and data edges.
tCQQO and tCQOH are skew between the C or Cn (or K or Kn in single-clock mode) and the CQ or CQn clocks.
When writing to QDRII SRAM devices, data is generated by the write
clock, while the K clock is 90° shifted from the write clock, creating a
center-aligned arrangement.
f
Go to www.qdrsram.com for the QDR SRAM and QDRII SRAM
specifications. For more information on QDR and QDRII SRAM
interfaces in Stratix and Stratix GX devices, see AN 349: QDR SRAM
Controller Reference Design for Stratix & Stratix GX Devices.
ZBT SRAM
ZBT SRAM eliminate dead bus cycles when turning a bidirectional bus
around between reads and writes or between writes and reads. ZBT
allows for 100% bus utilization because ZBT SRAM can be read or written
on every clock cycle. Bus contention can occur when shifting from a write
cycle to a read cycle or vice versa with no idle cycles in between.
ZBT SRAM allows small amounts of bus contention. To avoid bus
contention, the output clock-to-low-impedance time (tZX) must be greater
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External Memory Interfaces in Stratix & Stratix GX Devices
than the clock-to-high-impedance time (tXZ). Stratix and Stratix GX device
I/O pins can interface with ZBT SRAM devices at up to 200 MHz and can
meet ZBT tCO and tSU timing requirements by controlling phase delay in
clocks to the OE or output and input registers using an enhanced PLL.
Figure 3–6 shows a flow-through ZBT SRAM operation where A1 and A3
are read addresses and A2 and A4 are write addresses. For pipelined
ZBT SRAM operation, data is delayed by another clock cycle. Stratix and
Stratix GX devices support up to 200-MHz ZBT SRAM operation using
the 2.5-V or 3.3-V LVTTL I/O standard.
Figure 3–6. tZX & tXZ Timing Diagram
tZX
clock
addr
A1
A2
A3
A4
tXZ
dataout
Q(A1)
Q(A3)
ZBT Bus Sharing
Device tZX
datain
D(A3)
wren
Interface Pins
ZBT SRAM uses one system clock input for all clocking purposes. Only
the rising edge of this clock is used, since ZBT SRAM uses a single data
rate scheme. The data bus, DQ, is bidirectional. There are three control
signals to the ZBT SRAM: RW_N, BW_N, and ADV_LD_N. You can use any
of the Stratix and Stratix GX device user I/O pins to interface to the
ZBT SRAM device.
f
Altera Corporation
June 2006
For more information on ZBT SRAM Interfaces in Stratix devices, see
AN 329: ZBT SRAM Controller Reference Design for Stratix & Stratix GX
Devices.
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DDR Memory Support Overview
DDR Memory
Support
Overview
Table 3–1 shows the external RAM support in Stratix EP1S10 through
EP1S40 devices and all Stratix GX devices. Table 3–2 shows the external
RAM support in Stratix EP1S60 and EP1S80 devices.
Table 3–1. External RAM Support in Stratix EP1S10 through EP1S40 & All Stratix GX Devices
Maximum Clock Rate (MHz)
DDR Memory Type
I/O
Standard
-5 Speed
Grade
-6 Speed Grade
Flip-Chip Flip-Chip
-7 Speed Grade
-8 Speed Grade
WireBond
FlipChip
WireBond
FlipChip
WireBond
DDR SDRAM (1),
(2)
SSTL-2
200
167
133
133
100
100
100
DDR SDRAM - side
banks (2), (3), (4)
SSTL-2
150
133
110
133
100
100
100
RLDRAM II (4)
1.8-V HSTL
200
(5)
(5)
(5)
(5)
(5)
(5)
QDR SRAM (6)
1.5-V HSTL
167
167
133
133
100
100
100
QDRII SRAM (6)
1.5-V HSTL
200
167
133
133
100
100
100
ZBT SRAM (7)
LVTTL
200
200
200
167
167
133
133
Notes to Table 3–1:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
These maximum clock rates apply if the Stratix device uses DQS phase-shift circuitry to interface with DDR
SDRAM. DQS phase-shift circuitry is only available on the top and bottom I/O banks (I/O banks 3, 4, 7, and 8).
For more information on DDR SDRAM, see AN 342: Interfacing DDR SDRAM with Stratix & Stratix GX Devices.
DDR SDRAM is supported on the Stratix device side I/O banks (I/O banks 1, 2, 5, and 6) without dedicated DQS
phase-shift circuitry. The read DQS signal is ignored in this mode.
These performance specifications are preliminary.
This device does not support RLDRAM II.
For more information on QDR or QDRII SRAM, see AN 349: QDR SRAM Controller Reference Design for Stratix &
Stratix GX Devices.
For more information on ZBT SRAM, see AN 329: ZBT SRAM Controller Reference Design for Stratix and Stratix GX
Devices.
Table 3–2. External RAM Support in Stratix EP1S60 & EP1S80
(Part 1 of 2)
Maximum Clock Rate (MHz)
DDR Memory Type
I/O Standard
-5 Speed Grade
-6 Speed Grade
-7 Speed Grade
SSTL-2
167
167
133
DDR SDRAM - side banks (2), (3) SSTL-2
150
133
133
QDR SRAM (4)
1.5-V HSTL
133
133
133
QDRII SRAM (4)
1.5-V HSTL
167
167
133
DDR SDRAM (1), (2)
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External Memory Interfaces in Stratix & Stratix GX Devices
Table 3–2. External RAM Support in Stratix EP1S60 & EP1S80
(Part 2 of 2)
Maximum Clock Rate (MHz)
DDR Memory Type
ZBT SRAM (5)
I/O Standard
LVTTL
-5 Speed Grade
-6 Speed Grade
-7 Speed Grade
200
200
167
Notes to Table 3–2:
(1)
(2)
(3)
(4)
(5)
These maximum clock rates apply if the Stratix device uses DQS phase-shift circuitry to interface with DDR
SDRAM. DQS phase-shift circuitry is only available on the top and bottom I/O banks (I/O banks 3, 4, 7, and 8).
For more information on DDR SDRAM, see AN 342: Interfacing DDR SDRAM with Stratix & Stratix GX Devices.
DDR SDRAM is supported on the side banks (I/O banks 1, 2, 5, and 6) with no dedicated DQS phase-shift circuitry.
The read DQS signal is ignored in this mode.
For more information on QDR or QDRII SRAM, see AN 349: QDR SRAM Controller Reference Design for Stratix &
Stratix GX Devices.
For more information on ZBT SRAM, see AN 329: ZBT SRAM Controller Reference Design for Stratix and Stratix GX
Devices.
Stratix and Stratix GX devices support the data strobe or read clock signal
(DQS) used in DDR SDRAM, and RLDRAM II devices. DQS signals are
associated with a group of data (DQ) pins.
Stratix and Stratix GX devices contain dedicated circuitry to shift the
incoming DQS signals by 0°, 72°, and 90°. The DQS phase-shift circuitry
uses a frequency reference to dynamically generate control signals for the
delay chains in each of the DQS pins, allowing it to compensate for
process, voltage, and temperature (PVT) variations. The dedicated
circuitry also creates consistent margins that meet your data sampling
window requirements.
f
Refer to the DC & Switching Characteristics chapter in volume 1 of the
Stratix Device Handbook for frequency limits regarding the 72 and 90°
phase shift for DQS.
In addition to the DQS dedicated phase-shift circuitry, every I/O element
(IOE) in Stratix and Stratix GX devices contains six registers and one latch
to achieve DDR operation. There is also a programmable delay chain in
the IOE that can help reduce contention when interfacing with ZBT
SRAM devices.
DDR Memory Interface Pins
Stratix and Stratix GX devices use data (DQ), data strobe (DQS), and clock
pins to interface with DDR SDRAM and RLDRAM II devices. This section
explains the pins used in the DDR SDRAM and RLDRAM II interfaces.
For QDR, QDRII, and ZBT SRAM interfaces, see the “External Memory
Standards” section.
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DDR Memory Support Overview
Figure 3–7 shows the DQ and DQS pins in ×8 mode.
Figure 3–7. Stratix & Stratix GX Device DQ & DQS Groups in × 8 Mode
Top or Bottom I/O Bank
DQ Pins (1)
DQS Pin
Note to Figure 3–7:
(1)
There are at least eight DQ pins per group.
Data & Data Strobe Pins
Stratix and Stratix GX data pins for the DDR memory interfaces are called
DQ pins. The Stratix and Stratix GX device I/O banks at the top (I/O
banks 3 and 4) and the bottom (I/O banks 7 and 8) of the device support
DDR SDRAM and RLDRAM II up to 200 MHz. These pins support DQS
signals with DQ bus modes of ×8, ×16, or ×32. Stratix and Stratix GX
devices can support either bidirectional data strobes or uni-directional
read clocks. Depending on the external memory interface, either the
memory device's read data strobes or read clocks feed the DQS pins.
For ×8 mode, there are up to 20 groups of programmable DQS and DQ
pins—10 groups in I/O banks 3 and 4 and 10 groups in I/O banks 7 and 8
(see Table 3–3). Each group consists of one DQS pin and a set of eight DQ
pins.
For ×16 mode, there are up to eight groups of programmable DQS and
DQ pins—four groups in I/O banks 3 and 4, and four groups in I/O
banks 7 and 8. The EP1S20 device supports seven ×16 mode groups. The
EP1S10 device does not support ×16 mode. All other devices support the
full eight groups. See Table 3–3. Each group consists of one DQS and 16
DQ pins. In ×16 mode, DQS1T, DQS3T, DQS6T, and DQS8T pins on the top
side of the device, and DQS1B, DQS3B, DQS6B, and DQS8B pins on the
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External Memory Interfaces in Stratix & Stratix GX Devices
bottom side of the device are dedicated DQS pins. The DQS2T, DQS7T,
DQS2B, and DQS7B pins are dedicated DQS pins for ×32 mode, and each
group consists of one DQS and 32 DQ pins.
Table 3–3. DQS & DQ Bus Mode Support
Device
Package
Note (1)
Number of ×8 Number of ×16
Groups
Groups
Number of ×32
Groups
672-pin BGA
672-pin FineLine BGA®
12 (2)
0
0
484-pin FineLine BGA
780-pin FineLine BGA
16 (3)
0
4
484-pin FineLine BGA
18 (4)
7 (5)
4
672-pin BGA
672-pin FineLine BGA
16 (3)
7 (5)
4
780-pin FineLine BGA
20
7 (5)
4
672-pin BGA
672-pin FineLine BGA
16 (3)
8
4
780-pin FineLine BGA
1,020-pin FineLine BGA
20
8
4
EP1S30
956-pin BGA
780-pin FineLine BGA
1,020-pin FineLine BGA
20
8
4
EP1S40
956-pin BGA
1,020-pin FineLine BGA
1,508-pin FineLine BGA
20
8
4
EP1S60
956-pin BGA
1,020-pin FineLine BGA
1,508-pin FineLine BGA
20
8
4
EP1S80
956-pin BGA
1,508-pin FineLine BGA
1,923-pin FineLine BGA
20
8
4
EP1S10
EP1S20
EP1S25
Notes to Table 3–3:
(1)
(2)
(3)
(4)
(5)
For VREF guidelines, see the Selectable I/O Standards in Stratix & Stratix GX Devices chapter of the Stratix Device
Handbook, Volume 2 or the Stratix GX Handbook, Volume 2.
These packages have six groups in I/O banks 3 and 4 and six groups in I/O banks 7 and 8.
These packages have eight groups in I/O banks 3 and 4 and eight groups in I/O banks 7 and 8.
This package has nine groups in I/O banks 3 and 4 and nine groups in I/O banks 7 and 8.
These packages have three groups in I/O banks 3 and 4 and four groups in I/O banks 7 and 8.
Altera Corporation
June 2006
3–13
Stratix Device Handbook, Volume 2
DDR Memory Support Overview
The DQS pins are marked in the Stratix and Stratix GX device pin table as
DQS[9..0]T or DQS[9..0]B, where T stands for top and B for bottom.
The corresponding DQ pins are marked as DQ[9..0]T[7..0], where
[9..0] indicates which DQS group the pins belong to. The numbering
scheme starts from right to left on the package bottom view. When not
used as DQ or DQS pins, these pins are available as user I/O pins.
You can also create a design in a mode other than the ×8, ×16, or ×32
mode. The Quartus® II software uses the next larger mode with the
unused DQ pins available as regular use I/O pins. For example, if you
create a design for ×9 mode for an RLDRAM II interface (nine DQ pins
driven by one DQS pin), the Quartus II software implements a ×16 mode
with seven DQ pins unconnected to the DQS bus. These seven unused
DQ pins can be used as regular I/O pins.
1
On the top and bottom side of the device, the DQ and DQS pins
must be configured as bidirectional DDR pins to enable the DQS
phase-shift circuitry. If you only want to use the DQ and/or
DQS pins as inputs, you need to set the output enable of the DQ
and/or DQS pins to ground. Use the altdqs and altdq
megafunctions to configure the DQS and DQ pins, respectively.
However, you should use the Altera® IP Toolbench to create the
data path for your memory interfaces.
Stratix and Stratix GX device side I/O banks (I/O banks 1, 2, 5, and 6)
support SDR SDRAM, ZBT SRAM, QDR SRAM, QDRII SRAM, and DDR
SDRAM interfaces and can use any of the user I/O pins in these banks for
the interface. Since these I/O banks do not have any dedicated circuitry
for memory interfacing, they can support DDR SDRAM up to 150 MHz
in -5 speed grade devices. However, these I/O banks do not support the
HSTL-18 Class II I/O standard, which is required to interface with
RLDRAM II.
Clock Pins
You can use any of the DDR I/O registers in the top or bottom bank of the
device (I/O banks 3, 4, 7, or 8) to generate clocks to the memory device.
You can also use any of the DDR I/O registers in the side I/O banks 1, 2,
5, or 6 to generate clocks for DDR SDRAM interfaces on the side I/O
banks (not using the DQS circuitry).
3–14
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
External Memory Interfaces in Stratix & Stratix GX Devices
Command & Address Pins
You can use any of the user I/O pins in the top or bottom bank of the
device (I/O banks 3, 4, 7, or 8) for commands and addresses. For DDR
SDRAM, you can also use any of the user I/O pins in the side I/O banks
1, 2, 5, or 6, regardless of whether you use the DQS phase-shift circuitry
or not.
Other Pins (Parity, DM, ECC & QVLD Pins)
You can use any of the DQ pins for the parity pins in Stratix and
Stratix GX devices. However, this may mean that you are using the next
larger DQS/DQ mode. For example, if you need a parity bit for each byte
of data, you are actually going to have nine DQ pins per DQS pin. The
Quartus II software then implements a ×16 mode, with the seven unused
DQ pins available as user I/O pins.
The data mask (DM) pins are only required when writing to
DDR SDRAM and RLDRAM II devices. A low signal on the DM pins
indicates that the write is valid. If the DM signal is high, the memory
masks the DQ signals. You can use any of the I/O pins in the same bank
as the DQ pins for the DM signals. Each group of DQS and DQ signals
requires a DM pin. The DDR register, clocked by the –90° shifted clock,
creates the DM signals, similar to DQ output signals.
Some DDR SDRAM devices support error correction coding (ECC),
which is a method of detecting and automatically correcting errors in
data transmission. Connect the DDR ECC pins to a Stratix and Stratix GX
device DQS/DQ group. In 72-bit DDR SDRAM, there are eight ECC pins
in addition to the 64 data pins. The memory controller needs extra logic
to encode and decode the ECC data.
QVLD pins are used in RLDRAM II interfacing to indicate the read data
availability. There is one QVLD pin per RLDRAM II device. A high on
QVLD indicates that the memory is outputting the data requested.
Similar to DQ inputs, this signal is edge-aligned with the RLDRAM II
read clocks, QK and QK#, and is sent half a clock cycle before data starts
coming out of the memory. You can connect QVLD pins to any of the I/O
pins in the same bank as the DQ pins for the QVLD signals.
DQS Phase-Shift Circuitry
Two single phase-shifting reference circuits are located on the top and
bottom of the Stratix and Stratix GX devices. Each circuit is driven by a
system reference clock that is of the same frequency as the DQS signal.
Clock pins CLK[15..12]p feed the phase-shift circuitry on the top of the
device and clock pins CLK[7..4]p feed the phase-shift circuitry on the
Altera Corporation
June 2006
3–15
Stratix Device Handbook, Volume 2
DDR Memory Support Overview
bottom of the device. The phase-shift circuitry cannot be fed from other
sources such as the LE or the PLL internal output clocks. This phase-shift
circuitry is used for DDR SDRAM and RLDRAM II interfaces. For best
performance, turn off the input reference clock to the DQS phase-shift
circuitry when reading from the DDR SDRAM or RLDRAM II. This is to
avoid any DLL jitter incorrectly shifting the DQS signal while the FPGA
is capturing data.
1
The I/O pins in I/O banks 1, 2, 5, and 6 can interface with the
DDR SDRAM at up to 150 MHz. See AN 342: Interfacing DDR
SDRAM with Stratix & Stratix GX Devices.
A compensated delay element on each DQS pin allows for either a 90° or
a 72° phase shift, which automatically centers input DQS signals with the
data valid window of their corresponding DQ data signals. The DQS
signals drive a local DQS bus within the top and bottom I/O banks. This
DQS bus is an additional resource to the I/O clocks and clocks DQ input
registers with the DQS signal.
f
Refer to the DC & Switching Characteristics chapter in volume 1 of the
Stratix Device Handbook for frequency limits regarding the 72 and 90°
phase shift for DQS.
The phase-shifting reference circuit on the top of the device controls the
compensated delay elements for all 10 DQS pins located at the top of the
device. The phase-shifting reference circuit on the bottom of the device
controls the compensated delay elements for all 10 DQS pins located on
the bottom of the device. All 10 delay elements (DQS signals) on either the
top or bottom of the device shift by the same degree amount. For
example, all 10 DQS pins on the top of the device can be shifted by 90° and
all 10 DQS pins on the bottom of the device can be shifted by 72°. The
reference circuit requires a maximum of 256 system reference clock cycles
to set the correct phase on the DQS delay elements.
1
This applies only to the initial phase calculation. Altera
recommends that you enable the DLL during the refresh cycle of
the DDR SDRAM. Enabling the DLL for the duration of the
minimum refresh time is sufficient for recalculating the phase
shift.
Figure 3–8 shows the phase-shift reference circuit control of each DQS
delay shift on the top of the device. This same circuit is duplicated on the
bottom of the device.
3–16
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Altera Corporation
June 2006
External Memory Interfaces in Stratix & Stratix GX Devices
Figure 3–8. DQS & DQSn Pins & the DQS Phase-Shift Circuitry
Note (1)
CLK[15..12] (2)
DQS
Pin
DQS
Pin
DQS
Pin
DQS
Pin
DQS
Pin
DQS
Pin
DQS
Pin
DQS
Pin
DQS
Pin
DQS
Pin
Compensated
Delay Element
Δt
Δt
Δt
Δt
Phase Shift
Reference
Circuit
Δt
Δt
Δt
Δt
Δt
Δt
DQS Bus
Notes to Figure 3–8:
(1)
(2)
There are up to 10 DQS and DQSn pins available on the top or the bottom of the Stratix and Stratix GX devices.
Clock pins CLK[15..12]p feed the phase-shift circuitry on the top of the device and clock pins CLK[7..4]p feed
the phase circuitry on the bottom of the device. The reference clock can also be used in the logic array.
The phase-shift circuitry is only used during read transactions where the
DQS pins are acting as input clocks or strobes. The phase-shift circuitry
can shift the incoming DQS signal by 0°, 72°, and 90°. The shifted DQS
signal is then inverted and used as a clock or a strobe at the DQ IOE input
registers.
f
Refer to the DC & Switching Characteristics chapter in volume 1 of the
Stratix Device Handbook for frequency limits regarding the 72 and 90°
phase shift for DQS.
The DQS phase-shift circuitry is bypassed when 0° shift is chosen. The
routing delay between the pins and the IOE registers is matched with
high precision for both the DQ and DQS signal when the 72° or 90° phase
shift is used. With the 0° phase shift, the skew between DQ and the DQS
signals at the IOE register has been minimized. See Table 3–4 for the
Quartus II software reported number on the DQ and DQS path to the IOE
when the DQS is set to 0° phase shift.
Table 3–4. Quartus II Reported Number on the DQS Path to the
IOE Note (1)
Altera Corporation
June 2006
Speed Grade
DQ2IOE
DQS2IOE
Unit
-5
0.908
1.008
ns
-6
0.956
1.061
ns
-7
1.098
1.281
ns
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Stratix Device Handbook, Volume 2
DDR Memory Support Overview
Table 3–4. Quartus II Reported Number on the DQS Path to the
IOE Note (1)
Speed Grade
DQ2IOE
DQS2IOE
Unit
-8
1.293
1.635
ns
Note to Table 3–4:
(1)
These are reported by Quartus II version 4.0. Check the latest version of the
Quartus II software for the most current information.
To generate the correct phase shift, you must provide a clock signal of the
same frequency as the DQS signal to the DQS phase-shift circuitry. Any
of the CLK[15..12]p clock pins can feed the phase circuitry on the top
of the device (I/O banks 3 and 4) and any of the CLK[7..4]p clock pins
can feed the phase circuitry on the bottom of the device (I/O banks 7
and 8). Both the top and bottom phase-shift circuits need unique clock
pins for the reference clock. You cannot use any internal clock sources to
feed the phase-shift circuitry, but you can route internal clock sources
off-chip and then back into one of the allowable clock input pins.
DLL
The DQS phase-shift circuitry uses a DLL to dynamically measure the
clock period needed by the DQS pin (see Figure 3–9). The DQS
phase-shift circuitry then uses the clock period to generate the correct
phase shift. The DLL in the Stratix and Stratix GX devices DQS phaseshift circuitry can operate between 100 and 200 MHz. The phase-shift
circuitry needs a maximum of 256 clock cycles to calculate the correct
phase shift. Data sent during these clock cycles may not be properly
captured.
1
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Stratix Device Handbook, Volume 2
You can still use the DQS phase-shift circuitry for DDR SDRAM
interfaces that are less than 100 MHz. The DQS signal is shifted
by about 2.5 ns. This shifted DQS signal is not in the center of the
DQ signals, but it is shifted enough to capture the correct data in
this low-frequency application.
Altera Corporation
June 2006
External Memory Interfaces in Stratix & Stratix GX Devices
Figure 3–9. Simplified Diagram of the DQS Phase-Shift Circuitry
Input
Reference
Clock
Phase
Comparator
Up/Down
Counter
Delay Chains
6
Control Signals
to DQS Pins
The input reference clock goes into the DLL to a chain of delay elements.
The phase comparator compares the signal coming out of the end of the
delay element chain to the input reference clock. The phase comparator
then issues the upndn signal to the up/down counter. This signal
increments or decrements a six-bit delay setting (control signals to DQS
pins) that increases or decreases the delay through the delay element
chain to bring the input reference clock and the signals coming out of the
delay element chain in phase.
The shifted DQS signal then goes to the DQS bus to clock the IOE input
registers of the DQ pins. It cannot go into the logic array for other
purposes.
For external memory interfaces that use a bidirectional read strobe like
DDR SDRAM, the DQS signal is low before going to or coming from a
high-impedance state (see Figure 3–1 on page 3–3). The state where DQS
is low just after a high-impedance state is called the preamble and the
state where DQS is low just before it returns to high-impedance state is
called the postamble. There are preamble and postamble specifications
for both read and write operations in DDR SDRAM. To ensure data is not
lost when there is noise on the DQS line at the end of a read postamble
time, you need to add soft postamble circuitry to disable the clocks at the
DQ IOE registers.
f
Altera Corporation
June 2006
For more information, the DQS Postamble soft logic is described in
AN 342: Interfacing DDR SDRAM with Stratix & Stratix GX Devices. The
Altera DDR SDRAM controller MegaCore® generates this logic as
open-source code.
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Stratix Device Handbook, Volume 2
DDR Memory Support Overview
DDR Registers
Each Stratix and Stratix GX IOE contains six registers and one latch. Two
registers and a latch are used for input, two registers are used for output,
and two registers are used for output enable control. The second output
enable register provides the write preamble for the DQS strobe in the
DDR external memory interfaces. This negative-edge output enable
register extends the high-impedance state of the pin by a half clock cycle
to provide the external memory's DQS preamble time specification.
Figure 3–10 shows the six registers and the latch in the Stratix and
Stratix GX IOE and Figure 3–11 shows how the second OE register
extends the DQS high impedance state by half a clock cycle during a write
operation.
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Altera Corporation
June 2006
External Memory Interfaces in Stratix & Stratix GX Devices
Figure 3–10. Bidirectional DDR I/O Path in Stratix & Stratix GX Devices
Note (1)
DFF
OE
(2)
D
Q
OR2
OE Register AOE (3)
1
0
(4)
DFF
D
Q
OE Register BOE (5)
DFF
datain_l
D
Q
0
1
TRI (6)
I/O Pin (7)
Output Register AO
DFF
Logic Array
datain_h
D
Q
Output Register BO
outclock
combout
DFF
dataout_h
Q
D
Input Register AI
LatchTCHLA
dataout_l
Q
D
DFF
neg_reg_out
Q
D
ENA
Latch C I
Input Register BI
inclock
Notes to Figure 3–10:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
All control signals can be inverted at the IOE. No programmable delay chains are shown in this diagram.
The OE signal is active low, but the Quartus II software implements this as active high and automatically adds an
inverter before input to the AOE register during compilation.
The AOE register generates the enable signal for general-purpose DDR I/O applications.
This select line is to choose whether the OE signal should be delayed by half-a-clock cycle.
The BOE register generates the delayed enable signal for the write strobes and write clock for memory interfaces.
The tristate enable is active low by default. You can design it to be active high. The combinational control path for
the tristate is not shown in this diagram.
You can also have combinational output to the I/O pin; this path is not shown in the diagram.
Altera Corporation
June 2006
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Stratix Device Handbook, Volume 2
DDR Memory Support Overview
Figure 3–11. Extending the OE Disable by Half-a-Clock Cycle for a Write Transaction
Note (1)
System clock
(outclock for DQS)
OE for DQS
(from logic array)
90˚
DQS
Delay
by Half
a Clock
Cycle
Preamble
Postamble
Write Clock
(outclock for DQ,
−90° phase shifted
from System Clock)
datain_h
(from logic array)
D0
D2
datain_l
(from logic array)
D1
D3
OE for DQ
(from logic array)
D0
DQ
D1
D2
D3
Note to Figure 3–11:
(1)
The waveform reflects the software simulation result. The OE signal is an active low on the device. However, the
Quartus II software implements this signal as an active high and automatically adds an inverter before the AOE
register D input.
Figures 3–12 and 3–13 summarize the IOE registers used for the DQ and
DQS signals.
3–22
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Altera Corporation
June 2006
External Memory Interfaces in Stratix & Stratix GX Devices
Figure 3–12. DQ Configuration in Stratix & Stratix GX IOE
Note (1)
DFF
(2)
D
OE
Q
OE Register AOE
DFF
D
datain_l
Q
0
1
Output Register AO
TRI
DQ Pin
DFF
Logic Array
D
datain_h
Q
Output Register BO
outclock (3)
DFF
Q
D
dataout_h
Input Register AI
Latch
TCH
LA
Q
dataout_l
D
DFF
neg_reg_out
Q
D
ENA
Latch C I
Input Register BI
inclock (from DQS bus)
(4)
Notes to Figure 3–12:
(1)
(2)
(3)
(4)
You can use the altdq megafunction to generate the DQ signals.
The OE signal is active low, but the Quartus II software implements this as active high and automatically adds an
inverter before the OE register AOE during compilation.
The outclock signal is phase shifted –90° from the system clock.
The shifted DQS signal must be inverted before going to the IOE. The inversion is automatic if you use the altdq
megafunction to generate the DQ signals.
Altera Corporation
June 2006
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Stratix Device Handbook, Volume 2
DDR Memory Support Overview
Figure 3–13. DQS Configuration in Stratix & Stratix GX IOE
Note (1)
DFF
OE
(2)
D
Q
OE Register AOE
OR2
1
0
(3)
DFF
D
Q
OE Register BOE
DFF
Logic Array
datain_h (3)
D
Q
0
Output Register AO
TRI
DQS Pin (5)
1
DFF
datain_l (4)
system clock
D
Q
Output Register BO
undelayed DQS (6)
combout (7)
DQS Phase
Shift Circuitry
(8)
Notes to Figure 3–13:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
You can use the altdqs megafunction to generate the DQS signals.
The OE signal is active low, but the Quartus II software implements this as active high and automatically adds an
inverter before OE register AOE during compilation.
The select line can be chosen in the altdqs MegaWizard Plug-In Manager.
The datain_l and datain_h pins are usually connected to VCC and ground, respectively.
DQS postamble handling is not shown in this diagram. For more information, see AN 342: Interfacing DDR SDRAM
with Stratix & Stratix GX Devices.
This undelayed DQS signal goes to the LE for the soft postamble circuitry.
You must invert this signal before it reaches the DQ IOE. This signal is automatically inverted if you use the altdq
megafunction to generate the DQ signals. Connect this port to the inclock port in the altdq megafunction.
DQS phase-shift circuitry is only available on DQS pins.
3–24
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
External Memory Interfaces in Stratix & Stratix GX Devices
The Stratix and Stratix GX DDR IOE structure requires you to invert the
incoming DQS signal by using a NOT gate to ensure proper data transfer.
The altdq megafunction automatically adds the inverter when it
generates the DQ signals. As shown in Figure 3–10, the inclock signal's
rising edge clocks the AI register, inclock signal's falling edge clocks
the BI register, and latch CI is opened when inclock is one. In a DDR
memory read operation, the last data coincides with DQS being low. If
you do not invert the DQS pin, you do not get this last data because the
latch does not open until the next rising edge of the DQS signal. The NOT
gate is inserted automatically if the altdg megafunction is used;
otherwise you need to add the NOT gate manually.
Figure 3–14 shows waveforms of the circuit shown in Figure 3–12. The
second set of waveforms in Figure 3–14 shows what happens if the
shifted DQS signal is not inverted; the last data, Dn, does not get latched
into the logic array as DQS goes to tristate after the read postamble time.
The third set of waveforms in Figure 3–14 shows a proper read operation
with the DQS signal inverted after the 90° shift; the last data Dn does get
latched. In this case the outputs of register AI and latch CI, which
correspond to dataout_h and dataout_l ports, are now switched
because of the DQS inversion.
Altera Corporation
June 2006
3–25
Stratix Device Handbook, Volume 2
DDR Memory Support Overview
Figure 3–14. DQ Captures with Non-Inverted & Inverted Shifted DQS
DQ & DQS Signals
DQ at the pin
Dn − 1
Dn
DQS at the pin
Shifted DQS Signal is Not Inverted
DQS shifted
by 90˚
Output of register A1
(dataout_h)
Output of register B1
Output of latch C1
(dataout_l)
Dn − 1
Dn − 2
Dn
Dn − 2
Shifted DQS Signal is Inverted
DQS inverted and
shifted by 90˚
Output of register A1
(dataout_h)
Output of register B1
Output of latch C1
(dataout_l)
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Stratix Device Handbook, Volume 2
Dn − 2
Dn
Dn − 1
Dn − 3
Dn − 1
Altera Corporation
June 2006
External Memory Interfaces in Stratix & Stratix GX Devices
PLL
When using the Stratix and Stratix GX top and bottom I/O banks (I/O
banks 3, 4, 7, or 8) to interface with a DDR memory, at least one PLL with
two outputs is needed to generate the system clock and the write clock.
The system clock generates the DQS write signals, commands, and
addresses. The write clock is –90° shifted from the system clock and
generates the DQ signals during writes.
When using the Stratix and Stratix GX side I/O banks 1, 2, 5, or 6 to
interface with DDR SDRAM devices, two PLLs may be needed per I/O
bank for best performance. The side I/O banks do not have dedicated
circuitry, so one PLL captures data from the DDR SDRAM and another
PLL generates the write signals, commands, and addresses to the
DDR SDRAM device. Stratix and Stratix GX devices side I/O banks can
support DDR SDRAM up to 150 MHz.
f
Conclusion
Altera Corporation
June 2006
For more information, see AN 342: Interfacing DDR SDRAM with Stratix
& Stratix GX Devices.
Stratix and Stratix GX devices support SDR SDRAM, DDR SDRAM,
RLDRAM II, QDR SDRAM, QDRII SRAM, and ZBT SRAM external
memories. Stratix and Stratix GX devices feature high-speed interfaces
that transfer data between external memory devices at up to
200 MHz/400 Mbps. Phase-shift circuitry in the Stratix and Stratix GX
devices allows you to ensure that clock edges are properly aligned.
3–27
Stratix Device Handbook, Volume 2
Conclusion
3–28
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Section III. I/O Standards
This section provides information on Stratix® single-ended, voltagereferenced, and differential I/O standards.
It contains the following chapters:
Revision History
■
Chapter 4, Selectable I/O Standards in Stratix & Stratix GX Devices
■
Chapter 5, High-Speed Differential I/O Interfaces in Stratix Devices
The table below shows the revision history for Chapters 4 and 5.
Chapter
Date/Version
4
June 2006, v3.4
●
Updated “AC Hot Socketing Specification” section.
July 2005, v3.3
●
●
Updated “Non-Voltage-Referenced Standards” section.
Minor change to Table 4–6.
●
Updated content throughout.
January 2005,
v3.2
Altera Corporation
Changes Made
Comments
Section III–1
I/O Standards
Chapter
Stratix Device Handbook, Volume 2
Date/Version
September 2004,
v3.1
Changes Made
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
April 2004, v3.0
●
●
●
November 2003,
v2.2
●
●
October 2003,
v2.1
●
●
July 2003, v2.0
●
●
●
●
●
●
Section III–2
Comments
Table 4–1 on page 4–1: renamed table, updated table, and
added Note 1.
Deleted Figure named “1.5-V Differential HSTL Class II
Termination.”
Updated text describing “SSTL-18 Class I & II - EIA/JEDEC
Preliminary Standard JC42.3” on page 4–11.
Updated HyperTransport data rates on page 4–17.
Changed HyperTransport device speed from 800 MHz to
400 MHz on page 4–17.
Added four rows to Table 4–2 on page 4–18: 1.5V HSTL Class I, 1.8-V HSTL Class I, 1.5-V HSTL Class II,
and 1.8-V HSTL Class II.
Changed title of Table 4–3 on page 4–21.
Updated Table 4–4 on page 4–22.
Updated Figure 4–20 on page 4–29.
Added description of which clock pins support differential
on-chip termination on page 4–30.
Updated description of flip-chip packages on page 4–31.
Changed title of Figure 4–21 on page 4–31.
Updated milliamps for non-thermally enhanced cavity up
and non-thermally enhanced FineLine BGA packages on
page 4–35.
Updated equation for FineLine BGA package on
page 4–35.
Updated milliamps in non-thermally enhanced cavity up and
non-thermally enhanced FineLine BGA packages
onpage 4–37.
Updated notes to Figure 4–18.
New information added to the “Hot Socketing” section.
New information added to the “Differential Pad Placement
Guidelines” section.
Removed support for series and parallel on-chip
termination.
Updated Figure 4–22.
Added the Output Enable Group Logic Option in Quartus II
and Toggle Rate Logic Option in Quartus II sections.
Updated notes to Table 4–10.
Renamed impedance matching to series termination
throughout Chapter.
Removed wide range specs for LVTTL and LVCMOS
standards pages 4-3 to 4-5.
Relaxed restriction of input pins next to differential pins for
flipchip packages (pages 4-20, 4-35, and 4-36).
Added Drive Strength section on page 4-26.
Removed text “for 10 ns or less” from AC Hot socketing
specification on page 4-27.
Added Series Termination column to Table 4-9.
Altera Corporation
I/O Standards
Chapter
Date/Version
5
July 2005, v3.2
September 2004,
v3.1
Changes Made
Updated Table 5–14 on page 5–58.
●
●
●
●
●
●
●
April 2004, v3.0
●
●
●
November 2003,
v2.2
●
●
Updated Note 3 in Table 5–10 on page 5–54.
Updated Table 5–7 on page 5–34.
Updated Table 5–8 on page 5–36.
Updated description of “RD Differential Termination” on
page 5–46.
Updated Note 5 in Table 5–14 on page 5–58.
Updated Notes 2, 5, and 7 in Table 5–11 on page 5–56
through Table 5–14 on page 5–58.
Added new text about spanning two I/O banks on
page 5–60.
Updated notes for Figure 5–17.
Updated Table 5–7, 5–8, and 5–10.
“Data Alignment with Clock” section, last sentence: change
made from 90 degrees to 180 degrees.
Removed support for series and parallel on-chip
termination.
Updated the number of channels per PLL in Tables 5-10
through 5-14.
October 2003,
v2.1
●
Added -8 speed grade device information, including Tables
5-7 and 5-8.
July 2003, v2.0
●
Format changes throughout Chapter.
Relaxed restriction of input pins next to differential pins for
flip chip packages in Figure 5-1, Note 5.
Wire bond package performance specification for “high”
speed channels was increased to 624 Mbps from 462 Mbps
throughout Chapter.
Updated high-speed I/O specification for J=2 in Tables 5-7
and 5-8.
Updated Tables 5-10 to 5-14 to reflect PLL cross-bank
support for high-speed differential channels at full speed.
Increased maximum output clock frequency to 462 to 500
MHz on page 5-66.
●
●
●
●
●
Altera Corporation
Comments
Section III–3
I/O Standards
Section III–4
Stratix Device Handbook, Volume 2
Altera Corporation
4. Selectable I/O Standards
in Stratix &
Stratix GX Devices
S52004-3.4
Introduction
The proliferation of I/O standards and the need for higher I/O
performance have made it critical that devices have flexible I/O
capabilities. Stratix® and Stratix GX programmable logic devices (PLDs)
feature programmable I/O pins that support a wide range of industry
I/O standards, permitting increased design flexibility. These I/O
capabilities enable fast time-to-market and high-performance solutions to
meet the demands of complex system designs. Additionally, Stratix and
Stratix GX devices simplify system board design and make it easy to
connect to microprocessors, peripherals, memories, gate arrays,
programmable logic circuits, and standard logic functions.
This chapter provides guidelines for using one or more industry I/O
standards in Stratix and Stratix GX devices, including:
■
■
■
■
■
■
■
■
Stratix & Stratix
GX I/O
Standards
Stratix and Stratix GX I/O standards
High-speed interfaces
Stratix and Stratix GX I/O banks
Programmable current drive strength
Hot socketing
Differential on-chip termination
I/O pad placement guidelines
Quartus® II software support
Stratix and Stratix GX devices support a wide range of industry I/O
standards as shown in the Stratix Device Family Data Sheet section in the
Stratix Device Handbook, Volume 1 and the Stratix GX Device Family Data
Sheet section of the Stratix GX Device Handbook, Volume 1. Several
applications that use these I/O standards are listed in Table 4–1.
Table 4–1. I/O Standard Applications & Performance (Part 1 of 2) Note (1)
I/O Standard
Altera Corporation
June 2006
Application
Performance
3.3-V LVTTL/LVCMOS
General purpose
350 MHz
2.5-V LVTTL/LVCMOS
General purpose
350 MHz
1.8-V LVTTL/LVCMOS
General purpose
250 MHz
1.5-V LVCMOS
General purpose
225 MHz
PCI/CompactPCI
PC/embedded systems
66 MHz
4–1
Stratix & Stratix GX I/O Standards
Table 4–1. I/O Standard Applications & Performance (Part 2 of 2) Note (1)
I/O Standard
Application
Performance
PCI-X 1.0
PC/embedded systems
133 MHz
AGP 1× and 2×
Graphics processors
66 to 133 MHz
SSTL-3 Class I and II
SDRAM
167 MHz
SSTL-2 Class I and II
DDR I SDRAM
160 to 400 Mbps
HSTL Class I
QDR SRAM/SRAM/CSIX
150 to 225 MHz
HSTL Class II
QDR SRAM/SRAM/CSIX
150 to 250 MHz
Differential HSTL
Clock interfaces
150 to 225 MHz
GTL
Backplane driver
200 MHz
GTL+
Pentium processor interface
133 to 200 MHz
LVDS
Communications
840 Mbps
HyperTransport
technology
Motherboard interfaces
800 Mbps
LVPECL
PHY interface
840 Mbps
PCML
Communications
840 Mbps
Differential SSTL-2
DDR I SDRAM
160 to 400 Mbps
CTT
Back planes and bus interfaces 200 MHz
Note to Table 4–1:
(1)
These performance values are dependent on device speed grade, package type
(flip-chip or wirebond) and location of I/Os (top/bottom or left/right). See the
DC & Switching Characteristics chapter of the Stratix Device Handbook, Volume 1.
3.3-V Low Voltage Transistor-Transistor Logic (LVTTL) EIA/JEDEC Standard JESD8-B
The 3.3-V LVTTL I/O standard is a general-purpose, single-ended
standard used for 3.3-V applications. The LVTTL standard defines the DC
interface parameters for digital circuits operating from a 3.0-V or 3.3-V
power supply and driving or being driven by LVTTL-compatible devices.
The LVTTL input standard specifies a wider input voltage range of
–0.5 V ≤VI ≤ 3.8 V. Altera allows an input voltage range of –0.5 V ≤VI ≤ 4.1
V. The LVTTL standard does not require input reference voltages or board
terminations.
Stratix and Stratix GX devices support both input and output levels for
3.3-V LVTTL operation.
4–2
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
3.3-V LVCMOS - EIA/JEDEC Standard JESD8-B
The 3.3-V low voltage complementary metal oxide semiconductor
(LVCMOS) I/O standard is a general-purpose, single-ended standard
used for 3.3-V applications. The LVCMOS standard defines the DC
interface parameters for digital circuits operating from a 3.0-V or 3.3-V
power supply and driving or being driven by LVCMOS-compatible
devices.
The LVCMOS standard specifies the same input voltage requirements as
LVTTL (–0.5 V ≤VI ≤ 3.8 V). The output buffer drives to the rail to meet the
minimum high-level output voltage requirements. The 3.3-V I/O
standard does not require input reference voltages or board terminations.
Stratix and Stratix GX devices support both input and output levels for
3.3-V LVCMOS operation.
2.5-V LVTTL Normal Voltage Range - EIA/JEDEC Standard
EIA/JESD8-5
The 2.5-V I/O standard is used for 2.5-V LVTTL applications. This
standard defines the DC interface parameters for high-speed, lowvoltage, non-terminated digital circuits driving or being driven by other
2.5-V devices. The input and output voltage ranges are:
■
■
The 2.5-V normal range input standards specify an input voltage
range of – 0.3 V ≤ VI ≤ 3.0 V.
The normal range minimum high-level output voltage requirement
(VOH) is 2.1 V.
Stratix and Stratix GX devices support both input and output levels for
2.5-V LVTTL operation.
2.5-V LVCMOS Normal Voltage Range - EIA/JEDEC Standard
EIA/JESD8-5
The 2.5-V I/O standard is used for 2.5-V LVCMOS applications. This
standard defines the DC interface parameters for high-speed, lowvoltage, non-terminated digital circuits driving or being driven by other
2.5-V parts. The input and output voltage ranges are:
■
■
Altera Corporation
June 2006
The 2.5-V normal range input standards specify an input voltage
range of – 0.5 V ≤ VI ≤ 3.0 V.
The normal range minimum VOH requirement is 2.1 V.
4–3
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Standards
Stratix and Stratix GX devices support both input and output levels for
2.5-V LVCMOS operation.
1.8-V LVTTL Normal Voltage Range - EIA/JEDEC Standard
EIA/JESD8-7
The 1.8-V I/O standard is used for 1.8-V LVTTL applications. This
standard defines the DC interface parameters for high-speed, lowvoltage, non-terminated digital circuits driving or being driven by other
1.8-V parts. The input and output voltage ranges are:
■
■
The 1.8-V normal range input standards specify an input voltage
range of – 0.5 V ≤ VI ≤ 2.3 V.
The normal range minimum VOH requirement is VCCIO – 0.45 V.
Stratix and Stratix GX devices support both input and output levels for
1.8-V LVTTL operation.
1.8-V LVCMOS Normal Voltage Range - EIA/JEDEC Standard
EIA/JESD8-7
The 1.8-V I/O standard is used for 1.8-V LVCMOS applications. This
standard defines the DC interface parameters for high-speed, lowvoltage, non-terminated digital circuits driving or being driven by other
1.8-V devices. The input and output voltage ranges are:
■
■
The 1.8-V normal range input standards specify an input voltage
range of – 0.5 V ≤ VI ≤ 2.5 V.
The normal range minimum VOH requirement is VCCIO – 0.45 V.
Stratix and Stratix GX devices support both input and output levels for
1.8-V LVCMOS operation.
1.5-V LVCMOS Normal Voltage Range - EIA/JEDEC Standard
JESD8-11
The 1.5-V I/O standard is used for 1.5-V applications. This standard
defines the DC interface parameters for high-speed, low-voltage, nonterminated digital circuits driving or being driven by other 1.5-V devices.
The input and output voltage ranges are:
■
■
The 1.5-V normal range input standards specify an input voltage
range of – 0.5 V ≤ VI ≤ 2.0 V.
The normal range minimum VOH requirement is 1.05 V.
4–4
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Stratix and Stratix GX devices support both input and output levels for
1.5-V LVCMOS operation.
1.5-V HSTL Class I & II - EIA/JEDEC Standard EIA/JESD8-6
The high-speed transceiver logic (HSTL) I/O standard is used for
applications designed to operate in the 0.0- to 1.5-V HSTL logic switching
range. This standard defines single ended input and output specifications
for all HSTL-compliant digital integrated circuits. The single ended input
standard specifies an input voltage range of – 0.3 V ≤ VI ≤ VCCIO + 0.3 V.
Stratix and Stratix GX devices support both input and output levels
specified by the 1.5-V HSTL I/O standard. The input clock is
implemented using dedicated differential input buffers. Two singleended output buffers are automatically programmed to have opposite
polarity so as to implement a differential output clock. Additionally, the
1.5-V HSTL I/O standard in Stratix and Stratix GX devices is compatible
with the 1.8-V HSTL I/O standard in APEXTM 20KE and APEX 20KC
devices because the input and output voltage thresholds are compatible.
See Figures 4–1 and 4–2. Stratix and Stratix GX devices support both
input and output levels with VREF and VTT.
Figure 4–1. HSTL Class I Termination
VTT = 0.75 V
Output Buffer
50 Ω
Z = 50 Ω
Input Buffer
VREF = 0.75 V
Figure 4–2. HSTL Class II Termination
VTT = 0.75 V
VTT = 0.75 V
Output Buffer
50 Ω
50 Ω
Z = 50 Ω
Input Buffer
VREF = 0.75 V
Altera Corporation
June 2006
4–5
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Standards
1.5-V Differential HSTL - EIA/JEDEC Standard EIA/JESD8-6
The differential HSTL I/O standard is used for applications designed to
operate in the 0.0- to 1.5-V HSTL logic switching range such as quad data
rate (QDR) memory clock interfaces. The differential HSTL specification
is the same as the single ended HSTL specification. The standard specifies
an input voltage range of – 0.3 V ≤ VI ≤ VCCIO + 0.3 V. Differential HSTL
does not require an input reference voltage, however, it does require a
50 Ω resistor termination resistor to VTT at the input buffer (see
Figure 4–3). Stratix and Stratix GX devices support both input and output
clock levels for 1.5-V differential HSTL. The input clock is implemented
using dedicated differential input buffer. Two single-ended output
buffers are automatically programmed to have opposite polarity so as to
implement a differential output clock.
Figure 4–3. 1.5-V Differential HSTL Class I Termination
VTT = 0.75 V
Differential
Transmitter
50 Ω
VTT = 0.75 V
50 Ω
Differential
Receiver
Z0 = 50 Ω
Z0 = 50 Ω
3.3-V PCI Local Bus - PCI Special Interest Group PCI Local Bus
Specification Rev. 2.3
The PCI local bus specification is used for applications that interface to
the PCI local bus, which provides a processor-independent data path
between highly integrated peripheral controller components, peripheral
add-in boards, and processor/memory systems. The conventional PCI
specification revision 2.3 defines the PCI hardware environment
including the protocol, electrical, mechanical, and configuration
specifications for the PCI devices and expansion boards. This standard
requires 3.3-V VCCIO. Stratix and Stratix GX devices are fully compliant
with the 3.3-V PCI Local Bus Specification Revision 2.3 and meet
64-bit/66-MHz operating frequency and timing requirements. The 3.3-V
PCI standard does not require input reference voltages or board
terminations. Stratix and Stratix GX devices support both input and
output levels.
4–6
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
3.3-V PCI-X 1.0 Local Bus - PCI-SIG PCI-X Local Bus
Specification Revision 1.0a
The PCI-X 1.0 standard is used for applications that interface to the PCI
local bus. The standard enables the design of systems and devices that
operate at clock speeds up to 133 MHz, or 1 gigabit per second (Gbps) for
a 64-bit bus. The PCI-X 1.0 protocol enhancements enable devices to
operate much more efficiently, providing more usable bandwidth at any
clock frequency. By using the PCI-X 1.0 standard, devices can be designed
to meet PCI-X 1.0 requirements and operate as conventional 33- and
66-MHz PCI devices when installed in those systems. This standard
requires 3.3-V VCCIO. Stratix and Stratix GX devices are fully compliant
with the 3.3-V PCI-X Specification Revision 1.0a and meet the 133-MHz
operating frequency and timing requirements. The 3.3-V PCI standard
does not require input reference voltages or board terminations. Stratix
and Stratix GX devices support both input and output levels.
3.3-V Compact PCI Bus - PCI SIG PCI Local Bus Specification
Revision 2.3
The Compact PCI local bus specification is used for applications that
interface to the PCI local bus. It follows the PCI Local Bus Specification
Revision 2.3 plus additional requirements in PCI Industrial Computers
Manufacturing Group (PICMG) specifications PICMG 2.0 R3.0,
CompactPCI specification, and the hot swap requirements in PICMG 2.1
R2.0, CompactPCI Hot Swap Specification. This standard has similar
electrical requirements as LVTTL and requires 3.3-V VCCIO. Stratix and
Stratix GX devices are compliant with the Compact PCI electrical
requirements. The 3.3-V PCI standard does not require input reference
voltages or board terminations. Stratix and Stratix GX devices support
both input and output levels.
3.3-V 1× AGP - Intel Corporation Accelerated Graphics Port
Interface Specification 2.0
The AGP interface is a platform bus specification that enables highperformance graphics by providing a dedicated high-speed port for the
movement of large blocks of 3-dimensional texture data between a PC's
graphics controller and system memory. The 1× AGP I/O standard is a
single-ended standard used for 3.3-V graphics applications. The 1× AGP
input standard specifies an input voltage range of
– 0.5 V ≤ VI ≤ VCCIO + 0.5 V. The 1× AGP standard does not require input
reference voltages or board terminations. Stratix and Stratix GX devices
support both input and output levels.
Altera Corporation
June 2006
4–7
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Standards
3.3-V 2× AGP - Intel Corporation Accelerated Graphics Port
Interface Specification 2.0
The 2× AGP I/O standard is a voltage-referenced, single-ended standard
used for 3.3-V graphics applications. The 2× AGP input standard
specifies an input voltage range of – 0.5V ≤ VI ≤ VCCIO + 0.5V. The 2× AGP
standard does not require board terminations. Stratix and Stratix GX
devices support both input and output levels.
GTL - EIA/JEDEC Standard EIA/JESD8-3
The GTL I/O standard is a low-level, high-speed back plane standard
used for a wide range of applications from ASICs and processors to
interface logic devices. The GTL standard defines the DC interface
parameters for digital circuits operating from power supplies of 2.5, 3.3,
and 5.0 V. The GTL standard is an open-drain standard, and Stratix and
Stratix GX devices support a 2.5- or 3.3-V VCCIO to meet this standard.
GTL requires a 0.8-V VREF and open-drain outputs with a 1.2-V VTT (see
Figure 4–4). Stratix and Stratix GX devices support both input and output
levels.
Figure 4–4. GTL Termination
VTT = 1.2 V
Output Buffer
VTT = 1.2 V
50 Ω
Z = 50 Ω
50 Ω
Input Buffer
VREF = 0.8 V
GTL+
The GTL+ I/O standard is used for high-speed back plane drivers and
Pentium processor interfaces. The GTL+ standard defines the DC
interface parameters for digital circuits operating from power supplies of
2.5, 3.3, and 5.0 V. The GTL+ standard is an open-drain standard, and
Stratix and Stratix GX devices support a 2.5- or 3.3-V VCCIO to meet this
standard. GTL+ requires a 1.0-V VREF and open-drain outputs with a
1.5-V VTT (see Figure 4–5). Stratix and Stratix GX devices support both
input and output levels.
4–8
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Figure 4–5. GTL+ Termination
VTT = 1.5 V
VTT = 1.5 V
Output Buffer
50 Ω
50 Ω
Z = 50 Ω
Input Buffer
VREF = 1.0 V
CTT - EIA/JEDEC Standard JESD8-4
The CTT I/O standard is used for backplanes and memory bus interfaces.
The CTT standard defines the DC interface parameters for digital circuits
operating from 2.5- and 3.3-V power supplies. The CTT standard does not
require special circuitry to interface with LVTTL or LVCMOS devices
when the CTT driver is not terminated. The CTT standard requires a 1.5-V
VREF and a 1.5-V VTT (see Figure 4–6). Stratix and Stratix GX devices
support both input and output levels.
Figure 4–6. CTT Termination
VTT = 1.5 V
Output Buffer
50 Ω
Z = 50 Ω
Input Buffer
VREF = 1.5 V
SSTL-3 Class I & II - EIA/JEDEC Standard JESD8-8
The SSTL-3 I/O standard is a 3.3-V memory bus standard used for
applications such as high-speed SDRAM interfaces. This standard
defines the input and output specifications for devices that operate in the
SSTL-3 logic switching range of 0.0 to 3.3 V. The SSTL-3 standard specifies
an input voltage range of – 0.3 V ≤ VI ≤ VCCIO + 0.3 V. SSTL-3 requires a 1.5V VREF and a 1.5-V VTT to which the series and termination resistors are
connected (see Figures 4–7 and 4–8). Stratix and Stratix GX devices
support both input and output levels.
Altera Corporation
June 2006
4–9
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Standards
Figure 4–7. SSTL-3 Class I Termination
VTT = 1.5 V
Output Buffer
50 Ω
25 Ω
Z = 50 Ω
Input Buffer
VREF = 1.5 V
Figure 4–8. SSTL-3 Class II Termination
VTT = 1.5 V
VTT = 1.5 V
50 Ω
50 Ω
Output Buffer
25 Ω
Z = 50 Ω
Input Buffer
VREF = 1.5 V
SSTL-2 Class I & II - EIA/JEDEC Standard JESD8-9A
The SSTL-2 I/O standard is a 2.5-V memory bus standard used for
applications such as high-speed DDR SDRAM interfaces. This standard
defines the input and output specifications for devices that operate in the
SSTL-2 logic switching range of 0.0 to 2.5 V. This standard improves
operation in conditions where a bus must be isolated from large stubs.
The SSTL-2 standard specifies an input voltage range of
– 0.3 V ≤ VI ≤ VCCIO + 0.3 V. SSTL-2 requires a 1.25-V VREF and a 1.25-V
VTT to which the series and termination resistors are connected (see
Figures 4–9 and 4–10). Stratix and Stratix GX devices support both input
and output levels.
Figure 4–9. SSTL-2 Class I Termination
VTT = 1.25 V
Output Buffer
50 Ω
25 Ω
Z = 50 Ω
Input Buffer
VREF = 1.25 V
4–10
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Figure 4–10. SSTL-2 Class II Termination
VTT = 1.25 V
VTT = 1.25 V
Output Buffer
50 Ω
25 Ω
50 Ω
Z = 50 Ω
Input Buffer
VREF = 1.25 V
SSTL-18 Class I & II - EIA/JEDEC Preliminary Standard JC42.3
The SSTL-18 I/O standard is a 1.8-V memory bus standard. This standard
is similar to SSTL-2 and defines input and output specifications for
devices that are designed to operate in the SSTL-18 logic switching range
0.0 to 1.8 V. SSTL-18 requires a 0.9-V VREF and a 0.9-V VTT to which the
series and termination resistors are connected. See Figures 4–11 and 4–12
for details on SSTL-18 Class I and II termination. Stratix and Stratix GX
devices support both input and output levels.
Figure 4–11. SSTL-18 Class I Termination
VTT = 0.9 V
Output Buffer
50 Ω
25 Ω
Z = 50 Ω
Input Buffer
VREF = 0.9 V
Figure 4–12. SSTL-18 Class II Termination
VTT = 0.9 V
VTT = 0.9 V
50 Ω
50 Ω
Output Buffer
25 Ω
Z = 50 Ω
Input Buffer
VREF = 0.9 V
Differential SSTL-2 - EIA/JEDEC Standard JESD8-9A
The differential SSTL-2 I/O standard is a 2.5-V standard used for
applications such as high-speed DDR SDRAM clock interfaces. This
standard supports differential signals in systems using the SSTL-2
Altera Corporation
June 2006
4–11
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Standards
standard and supplements the SSTL-2 standard for differential clocks.
The differential SSTL-2 standard specifies an input voltage range of
– 0.3 V ≤ VI ≤ VCCIO + 0.3 V. The differential SSTL-2 standard does not
require an input reference voltage differential. See Figure 4–13 for details
on differential SSTL-2 termination. Stratix and Stratix GX devices support
output clock levels for differential SSTL-2 Class II operation. The output
clock is implemented using two single-ended output buffers which are
programmed to have opposite polarity.
Figure 4–13. Differential SSTL-2 Class II Termination
VTT = 1.25 V
Differential
Transmitter
50 Ω
VTT = 1.25 V
50 Ω
VTT = 1.25 V
50 Ω
VTT = 1.25 V
50 Ω
Differential
Receiver
25 Ω
Z0 = 50 Ω
25 Ω
Z0 = 50 Ω
LVDS - ANSI/TIA/EIA Standard ANSI/TIA/EIA-644
The LVDS I/O standard is a differential high-speed, low-voltage swing,
low-power, general-purpose I/O interface standard requiring a 3.3-V
VCCIO. This standard is used in applications requiring high-bandwidth
data transfer, backplane drivers, and clock distribution. The
ANSI/TIA/EIA-644 standard specifies LVDS transmitters and receivers
capable of operating at recommended maximum data signaling rates of
655 Mbps. However, devices can operate at slower speeds if needed, and
there is a theoretical maximum of 1.923 Gbps. Stratix and Stratix GX
devices meet the ANSI/TIA/EIA-644 standard.
Due to the low voltage swing of the LVDS I/O standard, the
electromagnetic interference (EMI) effects are much smaller than CMOS,
TTL, and PECL. This low EMI makes LVDS ideal for applications with
low EMI requirements or noise immunity requirements. The LVDS
standard does not require an input reference voltage, however, it does
require a 100 Ω termination resistor between the two signals at the input
buffer. Stratix and Stratix GX devices include an optional differential
LVDS termination resistor within the device using differential on-chip
termination. Stratix and Stratix GX devices support both input and
output levels.
4–12
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Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
f
For more information on the LVDS I/O standard in Stratix devices, see
the High-Speed Differential I/O Interfaces in Stratix Devices chapter.
LVPECL
The LVPECL I/O standard is a differential interface standard requiring a
3.3-V VCCIO. The standard is used in applications involving video
graphics, telecommunications, data communications, and clock
distribution. The high-speed, low-voltage swing LVPECL I/O standard
uses a positive power supply and is similar to LVDS, however, LVPECL
has a larger differential output voltage swing than LVDS. The LVPECL
standard does not require an input reference voltage, but it does require
a 100-Ω termination resistor between the two signals at the input buffer.
See Figures 4–14 and 4–15 for two alternate termination schemes for
LVPECL. Stratix and Stratix GX devices support both input and output
levels.
Figure 4–14. LVPECL DC Coupled Termination
Output Buffer
Input Buffer
Z = 50 Ω
100 Ω
Z = 50 Ω
Figure 4–15. LVPECL AC Coupled Termination
VCCIO
VCCIO
Output Buffer
10 to 100 nF
Z = 50 Ω
R1
R1
R2
R2
Input Buffer
100 Ω
10 to 100 nF
Z = 50 Ω
Pseudo Current Mode Logic (PCML)
The PCML I/O standard is a differential high-speed, low-power I/O
interface standard used in applications such as networking and
telecommunications. The standard requires a 3.3-V VCCIO. The PCML I/O
standard consumes less power than the LVPECL I/O standard. The
Altera Corporation
June 2006
4–13
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Standards
PCML standard is similar to LVPECL, but PCML has a reduced voltage
swing, which allows for a faster switching time and lower power
consumption. The PCML standard uses open drain outputs and requires
a differential output signal. See Figure 4–16 for details on PCML
termination. Stratix and Stratix GX devices support both input and
output levels.
Additionally, Stratix GX devices support 1.5-V PCML as described in the
Stratix GX Device Handbook, Volume 1.
Figure 4–16. PCML Termination
VTT
Output Buffer
50 Ω
50 Ω
Z = 50 Ω
50 Ω
50 Ω
Input Buffer
Z = 50 Ω
HyperTransport Technology - HyperTransport Consortium
The HyperTransport technology I/O standard is a differential highspeed, high-performance I/O interface standard requiring a 2.5-V VCCIO.
This standard is used in applications such as high-performance
networking, telecommunications, embedded systems, consumer
electronics, and Internet connectivity devices. The HyperTransport
technology I/O standard is a point-to-point standard in which each
HyperTransport technology bus consists of two point-to-point
unidirectional links. Each link is 2 to 32 bits. The HyperTransport
technology standard does not require an input reference voltage.
However, it does require a 100-Ω termination resistor between the two
signals at the input buffer. See Figure 4–17 for details on HyperTransport
technology termination. Stratix and Stratix GX devices support both
input and output levels.
Figure 4–17. HyperTransport Technology Termination
Output Buffer
Input Buffer
Z = 50 Ω
100 Ω
Z = 50 Ω
4–14
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
f
High-Speed
Interfaces
See the Stratix Device Family Data Sheet section in the Stratix Device
Handbook, Volume 1; the Stratix GX Device Family Data Sheet section of the
Stratix GX Device Handbook, Volume 1; and the High-Speed Differential I/O
Interfaces in Stratix Devices chapter for more information on differential
I/O standards.
In addition to current industry physical I/O standards, Stratix and
Stratix GX devices also support a variety of emerging high-speed
interfaces. This section provides an overview of these interfaces.
OIF-SPI4.2
This implementation agreement is widely used in the industry for
OC-192 and 10-Gbps multi-service system interfaces. SONET and SDH
are synchronous transmission systems over which data packets are
transferred. POS-PHY Level 4 is a standard interface for switches and
routers, and defines the operation between a physical layer (PHY) device
and link layer devices (ATM, Internet protocol, and Gigabit Ethernet) for
bandwidths of OC-192 ATM, POS, and 10-Gigabit Ethernet applications.
Some key POS-PHY Level 4 system features include:
■
■
■
■
■
■
■
■
■
Large selection of POS-PHY Level 4-based PHYs
Independent of data protocol
Wide industry support
LVDS I/O standard to improve signal integrity
Inband addressing/control
Out of band flow control
Scalable architecture
Over 622-Mbps operation
Dynamic interface timing mode
POS-PHY Level 4 operates at a wide range of frequencies.
OIF-SFI4.1
This implementation agreement is widely used in the industry for
interfacing physical layer (PHY) to the serializer-deserializer (SERDES)
devices in OC-192 and 10 Gbps multi-service systems. The POS-PHY
Level 4 interface standard defines the SFI-4 standard. POS-PHY
Level 4: SFI-4 is a standardized 16-bit × 622-Mbps line-side interface for
10-Gbps applications. Internet LAN and WAN architectures use
telecommunication SONET protocols for data transferring data over the
PHY layer. SFI-4 interfaces between OC-192 SERDES and SONET
framers.
Altera Corporation
June 2006
4–15
Stratix Device Handbook, Volume 2
High-Speed Interfaces
10 Gigabit Ethernet Sixteen Bit Interface (XSBI) - IEEE Draft
Standard P802.3ae/D2.0
10 Gigabit Ethernet XSBI is an interface standard for LANs, metropolitan
area networks (MANs), storage area networks (SANs), and WANs.
10 Gigabit Ethernet XSBI provides many features for efficient, effective
high-speed networking, including easy migration to higher performance
levels without disruption, lower cost of ownership including acquisition
and support versus other alternatives, familiar management tools and
common skills, ability to support new applications and data protocols,
flexibility in network design, and multiple vendor sourcing and
interoperability.
Under the ISO Open Systems Interconnection (OSI) model, Ethernet is a
Layer 2 protocol. 10 Gigabit Ethernet XSBI uses the IEEE 802.3 Ethernet
media access control (MAC) protocol, Ethernet frame format, and the
minimum/maximum frame size. An Ethernet PHY corresponding to OSI
layer 1 connects the media to the MAC layer that corresponds to OSI
layer 2. The PHY is divided into a physical media dependent (PMD)
element, such as optical transceivers, and a physical coding sub-layer
(PCS), which has coding and a serializer/multiplexor. This standard
defines two PHY types, including the LAN PHY and the WAN PHY,
which are distinguished by the PCS. The 10 Gigabit Ethernet XSBI
standard is a full-duplex technology standard that can increase the speed
and distance of Ethernet.
RapidIO Interconnect Specification Revision 1.1
The RapidIO interface is a communications standard used to connect
devices on a circuit board and circuit boards on a backplane. RapidIO is a
packet-switched interconnect standard designed for embedded systems
such as those used in networking and communications. The RapidIO
interface standard is a high-performance interconnect interface used for
transferring data and control information between microprocessors,
DSPs, system memory, communications and network processors, and
peripheral devices in a system.
RapidIO replaces existing peripheral bus and processor technologies
such as PCI. Some features of RapidIO include multiprocessing support,
an open standard, flexible topologies, higher bandwidth, low latency,
error management support in hardware, small silicon footprint, widely
available process and I/O technologies, and transparency to existing
applications and operating system software. The RapidIO standard
provides 10-Gbps device bandwidth using 8-bit-wide input and output
data ports. RapidIO uses LVDS technology, has the capability to be scaled
to multi-GHz frequencies, and features a 10-bit interface.
4–16
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
HyperTransport Technology - HyperTransport Consortium
The HyperTransport technology I/O standard is a differential
high-speed, high performance I/O interface standard developed for
communications and networking chip-to-chip communications.
HyperTransport technology is used in applications such as highperformance networking, telecommunications, embedded systems,
consumer electronics, and Internet connectivity devices. The
HyperTransport technology I/O standard is a point-to-point (one source
connected to exactly one destination) standard that provides a highperformance interconnect between integrated circuits in a system, such as
on a motherboard.
Stratix devices support HyperTransport technology at data rates up to
800 Mbps and 32 bits in each direction. HyperTransport technology uses
an enhanced differential signaling technology to improve performance.
HyperTransport technology supports data widths of 2, 4, 8, 16, or 32 bits
in each direction. HyperTransport technology in Stratix and Stratix GX
devices operates at multiple clock speeds up to 400 MHz.
UTOPIA Level 4 – ATM Forum Technical Committee Standard AFPHY-0144.001
The UTOPIA Level 4 frame-based interface standard allows device
manufacturers and network developers to develop components that can
operate at data rates up to 10 Gbps. This standard increases interface
speeds using LVDS I/O and advanced silicon technologies for fast data
transfers.
UTOPIA Level 4 provides new control techniques and a 32-, 16-, or 8-bit
LVDS bus, a symmetric transmit/receive bus structure for easier
application design and testability, nominal data rates of 10 Gbps, in-band
control of cell delimiters and flow control to minimize pin count, sourcesynchronous clocking, and supports variable length packet systems.
UTOPIA Level 4 handles sustained data rates for OC-192 and supports
ATM cells. UTOPIA Level 4 also supports interconnections across
motherboards, daughtercards, and backplane interfaces.
Stratix & Stratix
GX I/O Banks
Altera Corporation
June 2006
Stratix devices have eight I/O banks in addition to the four enhanced PLL
external clock output banks, as shown in Table 4–2 and Figure 4–18. I/O
banks 3, 4, 7, and 8 support all single-ended I/O standards. I/O banks 1,
2, 5, and 6 support differential HSTL (on input clocks), LVDS, LVPECL,
PCML, and HyperTransport technology, as well as all single-ended I/O
standards except HSTL Class II, GTL, SSTL-18 Class II, PCI/PCI-X 1.0,
and 1× /2× AGP. The four enhanced PLL external clock output banks
(I/O banks 9, 10, 11, and 12) support clock outputs all single-ended I/O
4–17
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Banks
standards in addition to differential SSTL-2 and HSTL (both on the output
clock only). Since Stratix devices support both non-voltage-referenced
and voltage-referenced I/O standards, there are different guidelines
when working with either separately or when working with both.
Table 4–2. I/O Standards Supported in Stratix I/O Banks (Part 1 of 2)
Enhanced PLL External
Clock Output Banks
I/O Bank
I/O Standard
1
2
3
4
5
6
7
8
9
10
11
12
3.3-V LVTTL/LVCMOS
v
v
v
v
v
v
v
v
v
v
v
v
2.5-V LVTTL/LVCMOS
v
v
v
v
v
v
v
v
v
v
v
v
1.8-V LVTTL/LVCMOS
v
v
v
v
v
v
v
v
v
v
v
v
1.5-V LVCMOS
v
v
v
v
v
v
v
v
v
v
v
v
PCI/PCIX//Compact PCI
v
v
v
v
v
v
v
v
AGP 1×
v
v
v
v
v
v
v
v
AGP 2×
v
v
v
v
v
v
v
v
SSTL-3 Class I
v
v
v
v
v
v
v
v
v
v
v
v
SSTL-3 Class II
v
v
v
v
v
v
v
v
v
v
v
v
SSTL-2 Class I
v
v
v
v
v
v
v
v
v
v
v
v
SSTL-2 Class II
v
v
v
v
v
v
v
v
v
v
v
v
SSTL-18 Class I
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
SSTL-18 Class II
Differential SSTL-2
(output clocks)
HSTL Class I
v
v
v
v
v
v
v
v
v
v
v
v
1.5-V HSTL Class I
v
v
v
v
v
v
v
v
v
v
v
v
1.8-V HSTL Class I
v
v
v
v
v
v
v
v
v
v
v
v
HSTL Class II
v
v
v
v
v
v
v
v
1.5-V HSTL Class II
v
v
v
v
v
v
v
v
1.8-V HSTL Class II
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
v
Differential HSTL (input
clocks)
v
v
v
v
Differential HSTL (output
clocks)
GTL
4–18
Stratix Device Handbook, Volume 2
v
v
v
v
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Table 4–2. I/O Standards Supported in Stratix I/O Banks (Part 2 of 2)
Enhanced PLL External
Clock Output Banks
I/O Bank
I/O Standard
1
2
3
4
5
6
7
8
9
10
11
12
GTL+
v
v
v
v
v
v
v
v
v
v
v
v
CTT
v
v
v
v
v
v
v
v
v
v
v
v
LVDS
v
v
(1)
(1)
v
v
(1)
(1)
(2)
(2)
(2)
(2)
HyperTransport
technology
v
v
(1)
(1)
v
v
(1)
(1)
(2)
(2)
(2)
(2)
LVPECL
v
v
(1)
(1)
v
v
(1)
(1)
(2)
(2)
(2)
(2)
PCML
v
v
(1)
(1)
v
v
(1)
(1)
(2)
(2)
(2)
(2)
Notes to Table 4–2:
(1)
(2)
This I/O standard is only supported on input clocks in this I/O bank.
This I/O standard is only supported on output clocks in this I/O bank.
Altera Corporation
June 2006
4–19
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Banks
Figure 4–18. Stratix I/O Banks Notes (1), (2), (3)
DQS5T
9
DQS4T
PLL11
(5)
DQS1T
DQS0T
10
Bank 4
LVDS, LVPECL, 3.3-V PCML,
and HyperTransport I/O Block
and Regular I/O Pins (4)
(5)
I/O Banks 1, 2, 5, and 6 Support All
Single-Ended I/O Standards Except
Differential HSTL Output Clocks,
Differential SSTL-2 Output Clocks,
HSTL Class II, GTL, SSTL-18 Class II,
PCI, PCI-X 1.0, and AGP 1×/2×
PLL2
Bank 1
DQS2T
I/O Banks 3, 4, 9 & 10 Support
All Single-Ended I/O Standards
PLL1
Bank 8
PLL3
DQS8B
DQS7B
DQS6B
DQS5B
(5)
LVDS, LVPECL, 3.3-V PCML,
and HyperTransport I/O Block
and Regular I/O Pins (4)
11
VREF5B8 VREF4B8 VREF3B8 VREF2B8 VREF1B8
DQS9B
PLL4
I/O Banks 7, 8, 11 & 12 Support
All Single-Ended I/O Standards
(5)
LVDS, LVPECL, 3.3-V PCML,
and HyperTransport I/O Block
and Regular I/O Pins (4)
PLL8
DQS3T
VREF1B4 VREF2B4 VREF3B4 VREF4B4 VREF5B4 PLL10
LVDS, LVPECL, 3.3-V PCML,
and HyperTransport I/O Block
and Regular I/O Pins (4)
Bank 2
VREF1B2 VREF2B2 VREF3B2 VREF4B2
Bank 3
VREF1B1 VREF2B1 VREF3B1 VREF4B1
PLL5
12
PLL6
Bank 5
DQS6T
VREF4B5 VREF3B5 VREF2B5 VREF1B5
DQS7T
Bank 6
DQS8T
VREF1B3 VREF2B3 VREF3B3 VREF4B3 VREF5B3
VREF4B6 VREF3B6 VREF2B6 VREF1B6
DQS9T
PLL7
Bank 7
PLL12
VREF5B7 VREF4B7 VREF3B7 VREF2B7 VREF1B7
DQS4B
DQS3B
DQS2B
DQS1B
PLL9
DQS0B
Notes to Figure 4–18:
(1)
(2)
(3)
(4)
(5)
Figure 4–18 is a top view of the silicon die. This corresponds to a top-down view for non-flip-chip packages, but is
a reverse view for flip-chip packages.
Figure 4–18 is a graphic representation only. See the pin list and the Quartus II software for exact locations.
Banks 9 through 12 are enhanced PLL external clock output banks.
If the high-speed differential I/O pins are not used for high-speed differential signaling, they can support all of the
I/O standards except HSTL Class II, GTL, SSTL-18 Class II, PCI, PCI-X 1.0, and AGP 1×/2×.
For guidelines on placing single-ended I/O pads next to differential I/O pads, see “I/O Pad Placement Guidelines”
on page 4–30.
4–20
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Tables 4–3 and 4–4 list the I/O standards that Stratix GX enhanced and
fast PLL pins support. Figure 4–19 shows the I/O standards that each
Stratix GX I/O bank supports.
Table 4–3. I/O Standards Supported in Stratix & Stratix GX Enhanced PLL Pins
Input
Output
I/O Standard
INCLK
FBIN
PLLENABLE
EXTCLK
LVTTL
v
v
v
v
LVCMOS
v
v
v
v
2.5 V
v
v
v
1.8 V
v
v
v
1.5 V
v
v
v
3.3-V PCI
v
v
v
3.3-V PCI-X 1.0
v
v
v
LVPECL
v
v
v
3.3-V PCML
v
v
v
LVDS
v
v
v
HyperTransport technology
v
v
v
Differential HSTL
v
v
v
Differential SSTL
3.3-V GTL
v
v
v
3.3-V GTL+
v
v
v
1.5-V HSTL Class I
v
v
v
1.5-V HSTL Class II
v
v
v
SSTL-18 Class I
v
v
v
SSTL-18 Class II
v
v
v
SSTL-2 Class I
v
v
v
SSTL-2 Class II
v
v
v
SSTL-3 Class I
v
v
v
SSTL-3 Class II
v
v
v
AGP (1× and 2×)
v
v
v
CTT
v
v
v
Altera Corporation
June 2006
4–21
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Banks
Table 4–4. I/O Standards Supported in Stratix & Stratix GX Fast PLL Pins
Input
I/O Standard
INCLK
PLLENABLE
LVTTL
v
v
LVCMOS
v
v
2.5 V
v
1.8 V
v
1.5 V
v
3.3-V PCI
3.3-V PCI-X 1.0
LVPECL
v
3.3-V PCML
v
LVDS
v
HyperTransport technology
v
Differential HSTL
v
Differential SSTL
3.3-V GTL
3.3-V GTL+
1.5V HSTL Class I
v
1.5V HSTL Class II
SSTL-18 Class I
v
SSTL-18 Class II
SSTL-2 Class I
v
SSTL-2 Class II
v
SSTL-3 Class I
v
SSTL-3 Class II
v
AGP (1× and 2×)
CTT
4–22
Stratix Device Handbook, Volume 2
v
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Figure 4–19. Stratix GX I/O Banks
I/O Bank 2
I/O Banks 1 & 2 Support:
■ Differential I/O Standards
- True LVDS
- LVPECL
- 3.3-V PCML
- HyperTransport Technology
■ Single-Ended I/O Standard
- 3.3 -, 2.5 -, 1.8 -V LVTTL
- GTL+
- CTT
- SSTL-18 Class I
- SSTL-2 Class I and II
- SSTL-3 Class I and II
- 1.5 -, 1.8 -V HSTL Class I
I/O Bank 1
I/O Bank 3
I/O Bank 4
I/O Banks 3, 4, 6 & 7 Support:
■ 3.3-, 2.5-, 1.8-V LVTTL
■ 3.3-V PCI, PCI-X 1.0
■ GTL
■ GTL+
■ AGP
■ CTT
■ SSTL-18 Class I and II
■ SSTL-2 Class I and II
■ SSTL-3 Class I and II
■ HSTL Class I and II
Individual
Power Bus
I/O Bank 7
I/O Bank 6
I/O Bank 5
I/O Bank 5 Contains Transceiver Blocks
There is some flexibility with the number of I/O standards each Stratix
I/O bank can simultaneously support. The following sections provide
guidelines for mixing non-voltage-referenced and voltage-referenced
I/O standards in Stratix devices.
Altera Corporation
June 2006
4–23
Stratix Device Handbook, Volume 2
Stratix & Stratix GX I/O Banks
Non-Voltage-Referenced Standards
Each Stratix I/O bank has its own VCCIO pins and supports only one
VCCIO, either 1.5, 1.8, 2.5 or 3.3 V. A Stratix I/O bank can simultaneously
support any number of input signals with different I/O standard
assignments, as shown in Table 4–5.
Table 4–5. Acceptable Input Levels for LVTTL/LVCMOS
Acceptable Input Levels
Bank VCCIO
3.3 V
2.5 V
1.8 V
1.5 V
3.3 V
v
v
2.5 V
v
v
1.8 V
v (2)
v (2)
v
v (1)
1.5 V
v (2)
v (2)
v
v
Notes to Table 4–5:
(1)
(2)
Because the input signal will not drive to the rail, the input buffer does not
completely shut off, and the I/O current will be slightly higher than the default
value.
These input values overdrive the input buffer, so the pin leakage current will be
slightly higher than the default value.
For output signals, a single I/O bank can only support non-voltagereferenced output signals driving at the same voltage as VCCIO. A Stratix
I/O bank can only have one VCCIO value, so it can only drive out that one
value for non-voltage referenced signals. For example, an I/O bank with
a 2.5-V VCCIO setting can support 2.5-V LVTTL inputs and outputs,
HyperTransport technology inputs and outputs, and 3.3-V LVCMOS
inputs (not output or bidirectional pins).
1
If the output buffer overdrives the input buffer, you must turn
on the Allow voltage overdrive for LVTTL/LVCMOS option in
the Quartus II software. To see this option, click the Device &
Pin Options button in the Device page of the Settings dialog
box (Assignments menu). Then click the Pin Placement tab in
the Device & Pin Options dialog box.
Voltage-Referenced Standards
To accommodate voltage-referenced I/O standards, each Stratix I/O
bank supports multiple VREF pins feeding a common VREF bus. The
number of available VREF pins increases as device density increases. If
these pins are not used as VREF pins, they can not be used as generic I/O
pins.
4–24
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
An I/O bank featuring single-ended or differential standards can support
voltage-referenced standards as long as all voltage-referenced standards
use the same VREF setting. For example, although one I/O bank can
implement both SSTL-3 and SSTL-2 I/O standards, I/O pins using these
standards must be in different banks since they require different VREF
values
For voltage-referenced inputs, the receiver compares the input voltage to
the voltage reference and does not take into account the VCCIO setting.
Therefore, the VCCIO setting is irrelevant for voltage referenced inputs.
Voltage-referenced bidirectional and output signals must be the same as
the I/O bank’s VCCIO voltage. For example, although you can place an
SSTL-2 input pin in any I/O bank with a 1.25-V VREF level, you can only
place SSTL-2 output pins in an I/O bank with a 2.5-V VCCIO.
Mixing Voltage Referenced & Non-Voltage Referenced
Standards
Non-voltage referenced and voltage referenced pins can safely be mixed
in a bank by applying each of the rule-sets individually. For example, on
I/O bank can support SSTL-3 inputs and 1.8-V LVCMOS inputs and
outputs with a 1.8-V VCCIO and a 1.5-V VREF. Similarly, an I/O bank can
support 1.5-V LVCMOS, 3.3-V LVTTL (inputs, but not outputs), and
HSTL I/O standards with a 1.5-V VCCIO and 0.75-V VREF.
For the voltage-referenced examples, see the “I/O Pad Placement
Guidelines” section. For details on how the Quartus II software supports
I/O standards, see the “Quartus II Software Support”section.
Altera Corporation
June 2006
4–25
Stratix Device Handbook, Volume 2
Drive Strength
Drive Strength
Each I/O standard supported by Stratix and Stratix GX devices drives out
a minimum drive strength. When an I/O is configured as LVTTL or
LVCMOS I/O standards, you can specify the current drive strength, as
summarized in Table 4–7.
Standard Current Drive Strength
Each I/O standard supported by Stratix and Stratix GX devices drives out
a minimum drive strength. Table 4–6 summarizes the minimum drive
strength of each I/O standard.
Table 4–6. Minimum Current Drive Strength of Each I/O Standard
I/O Standard
Current Strength, IOL/IOH (mA)
GTL
40 (1)
GTL+
34 (1)
SSTL-3 Class I
8
SSTL-3 Class II
16
SSTL-2 Class I
8.1
SSTL-2 Class II
16.4
SSTL-18 Class I
6.7
SSTL-18 Class II
13.4
1.5-V HSTL Class I
8
1.5-V HSTL Class II
16
CTT
8
AGP 1×
IOL = 1.5, IOH = –0.5
Note to Table 4–6:
(1)
Because this I/O standard uses an open drain buffer, this value refers to IOL.
When the SSTL-2 Class I and II I/O standards are implemented on top or
bottom I/O pins, the drive strength is designed to be higher than the
drive strength of the buffer when implemented on side I/O pins. This
allows the top or bottom I/O pins to support 200-MHz operation with the
standard 35-pF load. At the same time, the current consumption when
using top or bottom I/O pins is higher than the side I/O pins. The high
current strength may not be necessary for certain applications where the
value of the load is less than the standard test load (e.g., DDR interface).
The Quartus II software allows you to reduce the drive strength when the
I/O pins are used for the SSTL-2 Class I or Class II I/O standard and
being implemented on the top or bottom I/O through the Current
Strength setting. Select the minimum strength for lower drive strength.
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June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Programmable Current Drive Strength
The Stratix and Stratix GX device I/O pins support various output
current drive settings as shown in Table 4–7. These programmable drive
strength settings help decrease the effects of simultaneously switching
outputs (SSO) in conjunction with reducing system noise. The supported
settings ensure that the device driver meets the IOH and IOL specifications
for the corresponding I/O standard.
Table 4–7. Programmable Drive Strength
I/O Standard
IOH / IOL Current Strength Setting (mA)
3.3-V LVTTL
24 (1), 16, 12, 8, 4
3.3-V LVCMOS
24 (2), 12 (1), 8, 4, 2
2.5-V LVTTL/LVCMOS
16 (1), 12, 8, 2
1.8-V LVTTL/LVCMOS
12 (1), 8, 2
1.5-V LVCMOS
8 (1), 4, 2
Notes to Table 4–7:
(1)
(2)
This is the Quartus II software default current setting.
I/O banks 1, 2, 5, and 6 do not support this setting.
These drive-strength settings are programmable on a per-pin basis (for
output and bidirectional pins only) using the Quartus II software. To
modify the current strength of a particular pin, see “Programmable Drive
Strength Settings” on page 4–40.
Hot Socketing
Stratix devices support hot socketing without any external components.
In a hot socketing situation, a device’s output buffers are turned off
during system power-up or power-down. Stratix and Stratix GX devices
support any power-up or power-down sequence (VCCIO and VCCINT) to
simplify designs. For mixed-voltage environments, you can drive signals
into the device before or during power-up or power-down without
damaging the device. Stratix and Stratix GX devices do not drive out until
the device is configured and has attained proper operating conditions.
Even though you can power up or down the VCCIO and VCCINT power
supplies in any sequence you should not power down any I/O bank(s)
that contains the configuration pins while leaving other I/O banks
powered on. For power up and power down, all supplies (VCCINT and all
VCCIO power planes) must be powered up and down within 100 ms of one
another. This prevents I/O pins from driving out.
Altera Corporation
June 2006
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Stratix Device Handbook, Volume 2
I/O Termination
You can power up or power down the VCCIO and VCCINT pins in any
sequence. The power supply ramp rates can range from 100 ns to 100 ms.
During hot socketing, the I/O pin capacitance is less than 15 pF and the
clock pin capacitance is less than 20 pF.
DC Hot Socketing Specification
The hot socketing DC specification is | IIOPIN | < 300 μ A.
AC Hot Socketing Specification
The hot socketing AC specification is | IIOPIN | < 8 mA for 10 ns or less.
This specification takes into account the pin capacitance, but not board
trace and external loading capacitance. Additional capacitance for trace,
connector, and loading must be considered separately.
IIOPIN is the current at any user I/O pin on the device. The DC
specification applies when all VCC supplies to the device are stable in the
powered-up or powered-down conditions. For the AC specification, the
peak current duration because of power-up transients is 10 ns or less. For
more information, refer to the Hot-Socketing & Power-Sequencing Feature &
Testing for Altera Devices white paper.
I/O Termination
Although single-ended, non-voltage-referenced I/O standards do not
require termination, Altera recommends using external termination to
improve signal integrity where required.
The following I/O standards do not require termination:
■
■
■
■
■
■
■
■
LVTTL
LVCMOS
2.5 V
1.8 V
1.5 V
3.3-V PCI/Compact PCI
3.3-V PCI-X 1.0
3.3-V AGP 1×
Voltage-Referenced I/O Standards
Voltage-referenced I/O standards require both an input reference
voltage, VREF, and a termination voltage, VTT. Off-chip termination on the
board should be used for series and parallel termination.
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June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
For more information on termination for voltage-referenced I/O
standards, see the Selectable I/O Standards in Stratix & Stratix GX Devices
chapter in the Stratix Device Handbook, Volume 2; or the Stratix GX Device
Handbook, Volume 2.
Differential I/O Standards
Differential I/O standards typically require a termination resistor
between the two signals at the receiver. The termination resistor must
match the differential load impedance of the bus. Stratix and Stratix GX
devices provide an optional differential termination on-chip resistor
when using LVDS.
See the High-Speed Differential I/O Interfaces in Stratix Devices chapter for
more information on differential I/O standards and their interfaces.
For differential I/O standards, I/O banks support differential
termination when VCCIO equals 3.3 V.
Differential Termination (RD)
Stratix devices support differential on-chip termination for sourcesynchronous LVDS signaling. The differential termination resistors are
adjacent to the differential input buffers on the device. This placement
eliminates stub effects, improving the signal integrity of the serial link.
Using differential on-chip termination resistors also saves board space.
Figure 4–20 shows the differential termination connections for Stratix and
Stratix GX devices.
Figure 4–20. Differential Termination
Differential
Transmitter
Stratix LVDS
Receiver Buffer with
Differential On-Chip Termination
Z0
RD
Z0
Altera Corporation
June 2006
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Stratix Device Handbook, Volume 2
I/O Pad Placement Guidelines
Differential termination for Stratix devices is supported for the left and
right I/O banks. Differential termination for Stratix GX devices is
supported for the left, source-synchronous I/O bank. Some of the clock
input pins are in the top and bottom I/O banks, which do not support
differential termination. Clock pins CLK[1,3,8,10] support differential
on-chip termination. Clock pins CLK[0,2,9,11], CLK[4-7], and CLK[12-15]
do not support differential on-chip termination.
Transceiver Termination
Stratix GX devices feature built-in on-chip termination within the
transceiver at both the transmit and receive buffers. This termination
improves signal integrity and provides support for the 1.5-V PCML I/O
standard.
I/O Pad
Placement
Guidelines
This section provides pad placement guidelines for the programmable
I/O standards supported by Stratix and Stratix GX devices and includes
essential information for designing systems using the devices' selectable
I/O capabilities. These guidelines will reduce noise problems so that
FPGA devices can maintain an acceptable noise level on the line from the
VCCIO supply. Since Altera FPGAs require that a separate VCCIO power
each bank, these noise issues do not have any effect when crossing bank
boundaries and these guidelines do not apply. Although pad placement
rules need not be considered between I/O banks, some rules must be
considered if you are using a VREF signal in a PLLOUT bank. Note that the
signals in the PLLOUT banks share the VREF supply with neighboring I/O
banks and, therefore, must adhere to the VREF rules discussed in “VREF
Pad Placement Guidelines”.
Differential Pad Placement Guidelines
To avoid cross coupling and maintain an acceptable noise level on the
VCCIO supply, there are restrictions on the placement of single-ended I/O
pads in relation to differential pads. Use the following guidelines for
placing single-ended pads with respect to differential pads in Stratix
devices. These guidelines apply for LVDS, HyperTransport technology,
LVPECL, and PCML I/O standards. The differential pad placement
guidelines do not apply for differential HSTL and differential SSTL
output clocks since each differential output clock is essentially
implemented using two single-ended output buffers. These rules do not
apply to differential HSTL input clocks either even though the dedicated
input buffers are used. However, both differential HSTL and differential
SSTL output standards must adhere to the single-ended (VREF) pad
placement restrictions discussed in “VREF Pad Placement Guidelines”.
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June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
■
■
For flip-chip packages, there are no restrictions for placement of
single-ended input signals with respect to differential signals (see
Figure 4–21). For wire-bond packages, single ended input pads may
only be placed four or more pads away from a differential pad.
Single-ended outputs and bidirectional pads may only be placed five
or more pads away from a differential pad (see Figure 4–21),
regardless of package type.
Figure 4–21. Legal Pin Placement Note (1)
Wirebond
Input
Input, Output,
Bidirectional
Differential Pin
FlipChip
Input
Input
Input, Output,
Bidirectional
Note to Figure 4–21:
(1)
Input pads on a flip-chip packages have no restrictions.
VREF Pad Placement Guidelines
Restrictions on the placement of single-ended voltage-referenced I/O
pads with respect to VREF pads help maintain an acceptable noise level
on the VCCIO supply and to prevent output switching noise from shifting
the VREF rail. The following guidelines are for placing single-ended pads
in Stratix devices.
Input Pins
Each VREF pad supports a maximum of 40 input pads with up to 20 on
each side of the VREF pad.
Output Pins
When a voltage referenced input or bidirectional pad does not exist in a
bank, there is no limit to the number of output pads that can be
implemented in that bank. When a voltage referenced input exists, each
VREF pad supports 20 outputs for thermally enhanced FineLine BGA®
and thermally enhanced BGA cavity up packages or 15 outputs for Nonthermally enhanced cavity up and non-thermally enhanced
FineLine BGA packages.
Altera Corporation
June 2006
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Stratix Device Handbook, Volume 2
I/O Pad Placement Guidelines
Bidirectional Pins
Bidirectional pads must satisfy input and output guidelines
simultaneously. If the bidirectional pads are all controlled by the same OE
and there are no other outputs or voltage referenced inputs in the bank,
then there is no case where there is a voltage referenced input active at the
same time as an output. Therefore, the output limitation does not apply.
However, since the bidirectional pads are linked to the same OE, the
bidirectional pads act as inputs at the same time. Therefore, the input
limitation of 40 input pads (20 on each side of the VREF pad) applies.
If any of the bidirectional pads are controlled by different output enables
(OE) and there are no other outputs or voltage referenced inputs in the
bank, then there may be a case where one group of bidirectional pads is
acting as inputs while another group is acting as outputs. In such cases,
apply the formulas shown in Table 4–8.
Table 4–8. Input-Only Bidirectional Pin Limitation Formulas
Package Type
Formula
Thermally enhanced FineLine BGA and <Total number of bidirectional pads> – <Total number of pads from the
thermally enhanced BGA cavity up
smallest group of pads controlled by an OE> ≤20 (per VREF pad)
Non-thermally enhanced cavity up and <Total number of bidirectional pads> – <Total number of pads from the
non-thermally enhanced FineLine BGA smallest group of pads controlled by an OE> ≤15 (per VREF pad).
Consider a thermally enhanced FineLine BGA package with eight
bidirectional pads controlled by OE1, eight bidirectional pads controlled
by OE2, and six bidirectional pads controlled by OE3. While this totals 22
bidirectional pads, it is safely allowable because there would be a
maximum of 16 outputs per VREF pad possible assuming the worst case
where OE1 and OE2 are active and OE3 is inactive. This is particularly
relevant in DDR SDRAM applications.
When at least one additional voltage referenced input and no other
outputs exist in the same VREF bank, then the bidirectional pad limitation
must simultaneously adhere to the input and output limitations. See the
following equation.
<Total number of bidirectional pads> + <Total number of input pads> ≤40 (20 on
each side of the VREF pad)
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June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
The previous equation accounts for the input limitations, but you must
apply the appropriate equation from Table 4–9 to determine the output
limitations.
Table 4–9. Bidirectional pad Limitation Formulas (Where VREF Inputs Exist)
Package Type
Formula
Thermally enhanced FineLine BGA and <Total number of bidirectional pads> ≤20 (per VREF pad)
thermally enhanced BGA cavity up
Non-thermally enhanced cavity up and <Total number of bidirectional pads> ≤15 (per VREF pad)
non-thermally enhanced FineLine BGA
When at least one additional output exists but no voltage referenced
inputs exist, apply the appropriate formula from Table 4–10.
Table 4–10. Bidirectional Pad Limitation Formulas (Where VREF Outputs Exist)
Package Type
Formula
Thermally enhanced FineLine BGA and <Total number of bidirectional pads> + <Total number of additional
thermally enhanced BGA cavity up
output pads> – <Total number of pads from the smallest group of pads
controlled by an OE> ≤20 (per VREF pad)
Non-thermally enhanced cavity up and <Total number of bidirectional pads> + <Total number of additional
non-thermally enhanced FineLine BGA output pads> – <Total number of pads from the smallest group of pads
controlled by an OE> ≤15 (per VREF pad)
When additional voltage referenced inputs and other outputs exist in the
same VREF bank, then the bidirectional pad limitation must again
simultaneously adhere to the input and output limitations. See the
following equation.
<Total number of bidirectional pads> + <Total number of input pads> ≤40 (20 on
each side of the VREF pad)
Altera Corporation
June 2006
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Stratix Device Handbook, Volume 2
I/O Pad Placement Guidelines
The previous equation accounts for the input limitations, but you must
apply the appropriate equation from Table 4–9 to determine the output
limitations.
Table 4–11. Bidirectional Pad Limitation Formulas (Multiple VREF Inputs & Outputs)
Package Type
Formula
Thermally enhanced FineLine BGA and <Total number of bidirectional pads> + <Total number of additional
thermally enhanced BGA cavity up
output pads> ≤20 (per VREF pad)
non-thermally enhanced cavity up and <Total number of bidirectional pads> + <Total number of additional
non-thermally enhanced FineLine BGA output pads> ≤15 (per VREF pad)
In addition to the pad placement guidelines, use the following guidelines
when working with VREF standards:
■
■
Each bank can only have a single VCCIO voltage level and a single
VREF voltage level at a given time. Pins of different I/O standards can
share the bank if they have compatible VCCIO values (see Table 4–12
for more details).
In all cases listed above, the Quartus II software generates an error
message for illegally placed pads.
Output Enable Group Logic Option in Quartus II
The Quartus II software can check a design to make sure that the pad
placement does not violate the rules mentioned above. When the
software checks the design, if the design contains more bidirectional pins
than what is allowed, the Quartus II software returns a fitting error. When
all the bidirectional pins are either input or output but not both (for
example, in a DDR memory interface), you can use the Output Enable
Group Logic option. Turning on this option directs the Quartus II Fitter
to view the specified nodes as an output enable group. This way, the Fitter
does not violate the requirements for the maximum number of pins
driving out of a VREF bank when a voltaged-referenced input pin or
bidirectional pin is present.
In a design that implements DDR memory interface with dq, dqs and dm
pins utilized, there are two ways to enable the above logic options. You
can enable the logic options through the Assignment Editor or by adding
the following assignments to your project’s ESF file:
OPTIONS_FOR_INDIVIDUAL_NODES_ONLY
{
dq : OUTPUT_ENABLE_GROUP 1;
dqs : OUTPUT_ENABLE_GROUP 1;
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Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
dm : OUTPUT_ENABLE_GROUP 1;
}
As a result, the Quartus II Fitter does not count the bidirectional pin
potential outputs, and the number of VREF bank outputs remains in the
legal range.
Toggle Rate Logic Option in Quartus II
You should specify the pin’s output toggling rate in order to perform a
stricter pad placement check in the Quartus II software. Specify the
frequency at which a pin toggles in the Quartus II Assignment Editor.
This option is useful for adjusting the pin toggle rate in order to place
them closer to differential pins. The option directs the Quartus II Fitter
toggle-rate checking while allowing you to place a single-ended pin
closer to a differential pin.
DC Guidelines
Variables affecting the DC current draw include package type and desired
termination methods. This section provides information on each of these
variables and also shows how to calculate the DC current for pin
placement.
1
The Quartus II software automatically takes these variables into
account during compilation.
For any 10 consecutive output pads in an I/O bank, Altera recommends
a maximum current of 200 mA for thermally enhanced FineLine BGA and
thermally enhanced BGA cavity up packages and 164 mA for
non-thermally enhanced cavity up and non-thermally enhanced FineLine
BGA packages. The following equation shows the current density
limitation equation for thermally enhanced FineLine BGA and thermally
enhanced BGA cavity up packages:
pin + 9
Σ
Ipin < 200 mA
pin
The following equation shows the current density limitation equation for
non-thermally enhanced cavity up and non-thermally enhanced
FineLine BGA packages:
Altera Corporation
June 2006
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Stratix Device Handbook, Volume 2
I/O Pad Placement Guidelines
pin + 9
Σ
Ipin < 164 mA
pin
Table 4–12 shows the DC current specification per pin for each I/O
standard. I/O standards not shown in the table do not exceed these
current limitations.
Table 4–12. I/O Standard DC Specification Note (1)
IPIN (mA)
Pin I/O Standard
3.3-V VCCIO
2.5-V VCCIO
1.5-V VCCIO
GTL
40
40
-
GTL+
34
34
-
SSTL-3 Class I
8
-
-
SSTL-3 Class II
16
-
-
CTT
8
-
-
SSTL-2 Class I
-
8.1
-
SSTL-2 Class II
-
16.4
-
HSTL Class I
-
-
8
HSTL Class II
-
-
16
Note to Table 4–12:
(1)
f
The current rating on a VREF pin is less than 10μA.
For more information on Altera device packaging, see the Package
Information for Stratix Devices chapter in the Stratix Device Handbook,
Volume 2.
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Altera Corporation
June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Figure 4–22. Current Draw Limitation Guidelines
I/O Pin Sequence
of an I/O Bank
Any 10 Consecutive I/O Pins,
VCC
GND
Any 10 consecutive I/O pads cannot exceed 200 mA in thermally
enhanced FineLine BGA and thermally enhanced BGA cavity up
packages or 164 mA in non-thermally enhanced cavity up and nonthermally enhanced FineLine BGA packages.
For example, consider a case where a group of 10 consecutive pads are
configured as follows for a thermally enhanced FineLine BGA and
thermally enhanced BGA cavity up package:
■
■
■
Number of SSTL-3 Class I output pads = 3
Number of GTL+ output pads = 4
The rest of the surrounding I/O pads in the consecutive group of 10
are unused
In this case, the total current draw for these 10 consecutive I/O pads
would be:
(# of SSTL-3 Class I pads × 8 mA) +
(# of GTL+ output pads × 34 mA) = (3 × 8 mA) + (4 × 34 mA) = 160 mA
In the above example, the total current draw for all 10 consecutive I/O
pads is less than 200 mA.
Altera Corporation
June 2006
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Stratix Device Handbook, Volume 2
Power Source of Various I/O Standards
Power Source of
Various I/O
Standards
For Stratix and Stratix GX devices, the I/O standards are powered by
different power sources. To determine which source powers the input
buffers, see Table 4–13. All output buffers are powered by VCCIO.
Table 4–13. The Relationships Between Various I/O Standards and the
Power Sources
I/O Standard
Quartus II
Software
Support
Power Source
2.5V/3.3V LVTTL
VCCIO
PCI/PCI-X 1.0
VCCIO
AGP
VCCIO
1.5V/1.8V
VCCIO
GTL
VCCINT
GTL+
VCCINT
SSTL
VCCINT
HSTL
VCCINT
CTT
VCCINT
LVDS
VCCINT
LVPECL
VCCINT
PCML
VCCINT
HyperTransport
VCCINT
You specify which programmable I/O standards to use for Stratix and
Stratix GX devices with the Quartus II software. This section describes
Quartus II implementation, placement, and assignment guidelines,
including
■
■
■
■
■
■
Compiler Settings
Device & Pin Options
Assign Pins
Programmable Drive Strength Settings
I/O Banks in the Floorplan View
Auto Placement & Verification
Compiler Settings
You make Compiler settings in the Compiler Settings dialog box
(Processing menu). Click the Chips & Devices tab to specify the device
family, specific device, package, pin count, and speed grade to use for
your design.
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June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Device & Pin Options
Click Device & Pin Options in the Compiler Settings dialog box to
access the I/O pin settings. For example, in the Voltage tab you can select
a default I/O standard for all pins for the targeted device. I/O pins that
do not have a specific I/O standard assignment default this standard.
Click OK when you are done setting I/O pin options to return to the
Compiler Settings dialog box.
Assign Pins
Click Assign Pins in the Compiler Settings dialog box to view the
device’s pin settings and pin assignments (see Figure 4–23). You can view
the pin settings under Available Pins & Existing Assignments. The
listing does not include VREF pins because they are dedicated pins. The
information for each pin includes:
■
■
■
■
■
■
■
■
Number
Name
I/O Bank
I/O Standard
Type (e.g., row or column I/O and differential or control)
SignalProbe Source Name
Enabled (that is, whether SignalProbe routing is enabled or disabled
Status
Figure 4–23. Assign Pins
Altera Corporation
June 2006
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Stratix Device Handbook, Volume 2
Quartus II Software Support
When you assign an I/O standard that requires a reference voltage to an
I/O pin, the Quartus II software automatically assigns VREF pins. See the
Quartus II Help for instructions on how to use an I/O standard for a pin.
Programmable Drive Strength Settings
To make programmable drive strength settings, perform the following
steps:
1.
In the Tools menu, choose Assignment Organizer.
2.
Choose the Edit specific entity & node settings for: setting, then
select the output or bidirectional pin to specify the current strength
for.
3.
In the Assignment Categories dialog box, select Options for
Individual Nodes Only.
4.
Select Click here to add a new assignment.
5.
In the Assignment dialog box, set the Name field to Current
Strength and set the Setting field to the desired, allowable value.
6.
Click Add.
7.
Click Apply, then OK.
I/O Banks in the Floorplan View
You can view the arrangement of the device I/O banks in the Floorplan
View (View menu) as shown in Figure 4–24. You can assign multiple I/O
standards to the I/O pins in any given I/O bank as long as the VCCIO of
the standards is the same. Pins that belong to the same I/O bank must use
the same VCCIO signal.
Each device I/O pin belongs to a specific, numbered I/O bank. The
Quartus II software color codes the I/O bank to which each I/O pin and
VCCIO pin belong. Turn on the Show I/O Banks option to display the I/O
bank color and the bank numbers for each pin.
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June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
Figure 4–24. Floorplan View Window
Auto Placement & Verification of Selectable I/O Standards
The Quartus II software automatically verifies the placement for all I/O
and VREF pins and performs the following actions.
■
■
■
■
■
Altera Corporation
June 2006
Automatically places I/O pins of different VREF standards without
pin assignments in separate I/O banks and enables the VREF pins of
these I/O banks.
Verifies that voltage-referenced I/O pins requiring different VREF
levels are not placed in the same bank.
Reports an error message if the current limit is exceeded for a Stratix
or Stratix GX power bank, as determined by the equation
documented in “DC Guidelines” on page 4–35.
Reserves the unused high-speed differential I/O channels and
regular user I/O pins in the high-speed differential I/O banks when
any of the high-speed differential I/O channels are being used.
Automatically assigns VREF pins and I/O pins such that the current
requirements are met and I/O standards are placed properly.
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Stratix Device Handbook, Volume 2
Conclusion
Conclusion
Stratix and Stratix GX devices provide the I/O capabilities to allow you
to work with current and emerging I/O standards and requirements.
Today’s complex designs demand increased flexibility to work with the
wide variety of available I/O standards and to simplify board design.
With Stratix and Stratix GX device features, such as hot socketing and
differential on-chip termination, you can reduce board design interface
costs and increase your development flexibility.
More
Information
For more information, see the following sources:
■
■
■
■
References
The Stratix Device Family Data Sheet section in the Stratix Device
Handbook, Volume 1
The Stratix GX Device Family Data Sheet section of the Stratix GX
Device Handbook, Volume 1
The High-Speed Differential I/O Interfaces in Stratix Devices chapter
AN 224: High-Speed Board Layout Guidelines
For more information, see the following references:
■
■
■
■
■
■
■
■
Stub Series Terminated Logic for 2.5-V (SSTL-2), JESD8-9B,
Electronic Industries Association, December 2000.
High-Speed Transceiver Logic (HSTL) – A 1.5-V Output Buffer
Supply Voltage Based Interface Standard for Digital Integrated
Circuits, EIA/JESD8-6, Electronic Industries Association, August
1995.
1.5-V +/- 0.1 V (Normal Range) and 0.9 V – 1.6 V (Wide Range)
Power Supply Voltage and Interface Standard for Non-terminated
Digital Integrated Circuits, JESD8-11, Electronic Industries
Association, October 2000.
1.8-V +/- 0.15 V (Normal Range) and 1.2 V – 1.95 V (Wide Range)
Power Supply Voltage and Interface Standard for Non-terminated
Digital Integrated Circuits, JESD8-7, Electronic Industries
Association, February 1997.
Center-Tap-Terminated (CTT) Low-Level, High-Speed Interface
Standard for Digital Integrated Circuits, JESD8-9A, Electronic
Industries Association, November 1993.
2.5-V +/- 0.2V (Normal Range) and 1.8-V to 2.7V (Wide Range)
Power Supply Voltage and Interface Standard for Non-terminated
Digital Integrated Circuits, JESD8-5, Electronic Industries
Association, October 1995.
Interface Standard for Nominal 3V/ 3.3-V Supply Digital Integrated
Circuits, JESD8-B, Electronic Industries Association, September 1999.
Gunning Transceiver Logic (GTL) Low-Level, High-Speed Interface
Standard for Digital Integrated Circuits, JESD8-3, Electronic
Industries Association, November 1993.
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June 2006
Selectable I/O Standards in Stratix & Stratix GX Devices
■
■
■
■
■
■
■
■
Altera Corporation
June 2006
Accelerated Graphics Port Interface Specification 2.0, Intel
Corporation.
Stub Series Terminated Logic for 1.8-V (SSTL-18), Preliminary JC42.3,
Electronic Industries Association.
PCI Local Bus Specification, Revision 2.2, PCI Special Interest Group,
December 1998.
PCI-X Local Bus Specification, Revision 1.0a, PCI Special Interest
Group.
UTOPIA Level 4, AF-PHY-0144.001, ATM Technical Committee.
POS-PHY Level 4: SPI-4, OIF-SPI4-02.0, Optical Internetworking
Forum.
POS-PHY Level 4: SFI-4, OIF-SFI4-01.0, Optical Internetworking
Forum.
Electrical Characteristics of Low Voltage Differential Signaling
(LVDS) Interface Circuits, ANSI/TIA/EIA-644, American National
Standards Institute/Telecommunications Industry/Electronic
Industries Association, October 1995.
4–43
Stratix Device Handbook, Volume 2
References
4–44
Stratix Device Handbook, Volume 2
Altera Corporation
June 2006
5. High-Speed Differential I/O
Interfaces in Stratix Devices
S52005-3.2
Introduction
To achieve high data transfer rates, Stratix® devices support TrueLVDSTM differential I/O interfaces which have dedicated
serializer/deserializer (SERDES) circuitry for each differential I/O pair.
Stratix SERDES circuitry transmits and receives up to 840 megabits per
second (Mbps) per channel. The differential I/O interfaces in Stratix
devices support many high-speed I/O standards, such as LVDS,
LVPECL, PCML, and HyperTransportTM technology. Stratix device highspeed modules are designed to provide solutions for many leading
protocols such as SPI-4 Phase 2, SFI-4, 10G Ethernet XSBI, RapidIO,
HyperTransport technology, and UTOPIA-4.
The SERDES transmitter is designed to serialize 4-, 7-, 8-, or 10-bit wide
words and transmit them across either a cable or printed circuit board
(PCB). The SERDES receiver takes the serialized data and reconstructs the
bits into a 4-, 7-, 8-, or 10-bit-wide parallel word. The SERDES contains the
necessary high-frequency circuitry, multiplexer, demultiplexer, clock,
and data manipulation circuitry. You can use double data rate I/O
(DDRIO) circuitry to transmit or receive differential data in by-one (×1)
or by-two (×2) modes.
1
Contact Altera Applications for more information on other B
values that the Stratix devices support and using ×7-mode in the
Quartus® II software. Stratix devices currently only support
B = 1 and B = 7 in ×7 mode.
This chapter describes the high-speed differential I/O capabilities of
Stratix programmable logic devices (PLDs) and provides guidelines for
their optimal use. You should use this document in conjunction with the
Stratix Device Family Data Sheet section of the Stratix Device Handbook,
Volume 1. Consideration of the critical issues of controlled impedance of
traces and connectors, differential routing, termination techniques, and
DC balance gets the best performance from the device. Therefore, an
elementary knowledge of high-speed clock-forwarding techniques is also
helpful.
Stratix I/O Banks
Altera Corporation
July 2005
Stratix devices contain eight I/O banks, as shown in Figure 5–1. The two
I/O banks on each side contain circuitry to support high-speed LVDS,
LVPECL, PCML, HSTL Class I and II, SSTL-2 Class I and II, and
HyperTransport inputs and outputs.
5–1
Stratix I/O Banks
Figure 5–1. Stratix I/O Banks Notes (1), (2), (3)
DQS5T
9
DQS4T
PLL11
(5)
DQS1T
DQS0T
10
Bank 4
LVDS, LVPECL, 3.3-V PCML,
and HyperTransport I/O Block
and Regular I/O Pins (4)
(5)
I/O Banks 1, 2, 5, and 6 Support All
Single-Ended I/O Standards Except
Differential HSTL Output Clocks,
Differential SSTL-2 Output Clocks,
HSTL Class II, GTL, SSTL-18 Class II,
PCI, PCI-X 1.0, and AGP 1×/2×
PLL2
Bank 1
DQS2T
I/O Banks 3, 4, 9 & 10 Support
All Single-Ended I/O Standards
PLL1
Bank 8
PLL3
DQS8B
DQS7B
DQS6B
DQS5B
(5)
LVDS, LVPECL, 3.3-V PCML,
and HyperTransport I/O Block
and Regular I/O Pins (4)
11
VREF5B8 VREF4B8 VREF3B8 VREF2B8 VREF1B8
DQS9B
PLL4
I/O Banks 7, 8, 11 & 12 Support
All Single-Ended I/O Standards
(5)
LVDS, LVPECL, 3.3-V PCML,
and HyperTransport I/O Block
and Regular I/O Pins (4)
PLL8
DQS3T
VREF1B4 VREF2B4 VREF3B4 VREF4B4 VREF5B4 PLL10
LVDS, LVPECL, 3.3-V PCML,
and HyperTransport I/O Block
and Regular I/O Pins (4)
Bank 2
VREF1B2 VREF2B2 VREF3B2 VREF4B2
Bank 3
VREF1B1 VREF2B1 VREF3B1 VREF4B1
PLL5
12
PLL6
Bank 5
DQS6T
VREF4B5 VREF3B5 VREF2B5 VREF1B5
DQS7T
Bank 6
DQS8T
VREF1B3 VREF2B3 VREF3B3 VREF4B3 VREF5B3
VREF4B6 VREF3B6 VREF2B6 VREF1B6
DQS9T
PLL7
Bank 7
PLL12
VREF5B7 VREF4B7 VREF3B7 VREF2B7 VREF1B7
DQS4B
DQS3B
DQS2B
DQS1B
PLL9
DQS0B
Notes to Figure 5–1:
(1)
(2)
(3)
(4)
(5)
Figure 5–1 is a top view of the Stratix silicon die, which corresponds to a top-down view of non-flip-chip packages
and a bottom-up view of flip-chip packages.
Figure 5–1 is a graphic representation only. See the pin list and the Quartus II software for exact locations.
Banks 9 through 12 are enhanced PLL external clock output banks.
If the high-speed differential I/O pins are not used for high-speed differential signaling, they can support all of the
I/O standards except HSTL Class I and II, GTL, SSTL-18 Class II, PCI, PCI-X 1.0, and AGP 1× /2× .
See “Differential Pad Placement Guidelines” on page 4–30. You can only place single-ended output/bidirectional
pads five or more pads away from a differential pad. Use the Show Pads view in the Quartus II Floorplan Editor to
locate these pads. The Quartus II software gives an error message for illegal output or bidirectional pin placement
next to a high-speed differential I/O pin.
Stratix Differential I/O Standards
Stratix devices provide a multi-protocol interface that allows
communication between a variety of I/O standards, including LVDS,
HyperTransport technology, LVPECL, PCML, HSTL Class I and II, and
5–2
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
SSTL-2 Class I and II. This feature makes the Stratix device family ideal
for applications that require multiple I/O standards, such as a protocol
translator.
f
For more information on termination for Stratix I/O standards, see
“Differential I/O Termination” on page 5–46.
Figure 5–2 compares the voltage levels between differential I/O
standards supported in all the Stratix devices.
Figure 5–2. Differential I/O Standards Supported by Stratix Devices
4.0
3.3 V
PCML
3.0 V
3.0
2.1 V
Voltage
(V)
2.0
LVPECL
1.7 V
1.4 V
LVDS
1.0
1.0 V
0.9 V
HyperTransport
0.3 V
0.0
Technology
Altera Corporation
July 2005
5–3
Stratix Device Handbook, Volume 2
Stratix I/O Banks
LVDS
The LVDS I/O standard is a differential high-speed, low-voltage swing,
low-power, general-purpose I/O interface standard requiring a 3.3-V
VCCIO. This standard is used in applications requiring high-bandwidth
data transfer, backplane drivers, and clock distribution. The
ANSI/TIA/EIA-644 standard specifies LVDS transmitters and receivers
capable of operating at recommended maximum data signaling rates of
655 Mbps. However, devices can operate at slower speeds if needed, and
there is a theoretical maximum of 1.923 Gbps. Stratix devices meet the
ANSI/TIA/EIA-644 standard.
Due to the low voltage swing of the LVDS I/O standard, the
electromagnetic interference (EMI) effects are much smaller than CMOS,
transistor-to-transistor logic (TTL), and PECL. This low EMI makes LVDS
ideal for applications with low EMI requirements or noise immunity
requirements. The LVDS standard specifies a differential output voltage
range of 0.25 V × VOD ≤ 0.45 V. The LVDS standard does not require an
input reference voltage, however, it does require a 100-Ω termination
resistor between the two signals at the input buffer. Stratix devices
include an optional differential termination resistor within the device. See
Section I, Stratix Device Family Data Sheet of the Stratix Device Handbook,
Volume 1 for the LVDS parameters.
HyperTransport Technology
The HyperTransport technology I/O standard is a differential highspeed, high-performance I/O interface standard requiring a 2.5-V
VCCIO. This standard is used in applications such as high-performance
networking, telecommunications, embedded systems, consumer
electronics, and Internet connectivity devices. The HyperTransport
technology I/O standard is a point-to-point standard in which each
HyperTransport technology bus consists of two point-to-point
unidirectional links. Each link is 2 to 32 bits. See the Stratix Device Family
Data Sheet section of the Stratix Device Handbook, Volume 1 for the
HyperTransport parameters.
LVPECL
The LVPECL I/O standard is a differential interface standard requiring a
3.3-V VCCIO. The standard is used in applications involving video
graphics, telecommunications, data communications, and clock
distribution. The high-speed, low-voltage swing LVPECL I/O standard
uses a positive power supply and is similar to LVDS, however, LVPECL
has a larger differential output voltage swing than LVDS. See the Stratix
Device Family Data Sheet section of the Stratix Device Handbook, Volume 1
for the LVPECL signaling characteristics.
5–4
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
PCML
The PCML I/O standard is a differential high-speed, low-power I/O
interface standard used in applications such as networking and
telecommunications. The standard requires a 3.3-V VCCIO. The PCML I/O
standard achieves better performance and consumes less power than the
LVPECL I/O standard. The PCML standard is similar to LVPECL, but
PCML has a reduced voltage swing, which allows for a faster switching
time and lower power consumption.See the Stratix Device Family Data
Sheet section of the Stratix Device Handbook, Volume 1 for the PCML
signaling characteristics.
Differential HSTL (Class I & II)
The differential HSTL I/O standard is used for applications designed to
operate in the 0.0- to 1.5-V HSTL logic switching range such as quad data
rate (QDR) memory clock interfaces. The differential HSTL specification
is the same as the single ended HSTL specification. The standard specifies
an input voltage range of – 0.3 V ≤ VI ≤ VCCIO + 0.3 V. The differential
HSTL I/O standard is only available on the input and output clocks. See
the Stratix Device Family Data Sheet section of the Stratix Device Handbook,
Volume 1 for the HSTL signaling characteristics
Differential SSTL-2 (Class I & II)
The differential SSTL-2 I/O standard is a 2.5-V memory bus standard
used for applications such as high-speed double data rate (DDR) SDRAM
interfaces. This standard defines the input and output specifications for
devices that operate in the SSTL-2 logic switching range of 0.0 to 2.5 V.
This standard improves operation in conditions where a bus must be
isolated from large stubs. The SSTL-2 standard specifies an input voltage
range of – 0.3 V ≤ VI ≤ VCCIO + 0.3 V. Stratix devices support both input
and output levels. The differential SSTL-2 I/O standard is only available
on output clocks. See the Stratix Device Family Data Sheet section of the
Stratix Device Handbook, Volume 1 for the SSTL-2 signaling characteristics.
Stratix Differential I/O Pin Location
The differential I/O pins are located on the I/O banks on the right and
left side of the Stratix device. Table 5–1 shows the location of the Stratix
device high-speed differential I/O buffers. When the I/O pins in the I/O
banks that support differential I/O standards are not used for high-speed
Altera Corporation
July 2005
5–5
Stratix Device Handbook, Volume 2
Principles of SERDES Operation
signaling, you can configure them as any of the other supported I/O
standards. DDRIO capabilities are detailed in “SERDES Bypass DDR
Differential Signaling” on page 5–42.
Table 5–1. I/O Pin Locations on Each Side of Stratix Devices
Differential Input
Differential Output
DDRIO
Left
Device Side (1)
v
v
v
Right
v
v
v
Top
v
Bottom
v
Note to Table 5–1:
(1)
Principles of
SERDES
Operation
Device sides are relative to pin A1 in the upper left corner of the device (top view
of the package).
Stratix devices support source-synchronous differential signaling up to
840 Mbps. Serial data is transmitted and received along with a lowfrequency clock. The PLL can multiply the incoming low-frequency clock
by a factor of 1 to 10. The SERDES factor J can be 4, 7, 8, or 10 and does not
have to equal the clock multiplication value. ×1 and ×2 operation is also
possible by bypassing the SERDES; it is explained in “SERDES Bypass
DDR Differential Interface Review” on page 5–42.
On the receiver side, the high-frequency clock generated by the PLL shifts
the serial data through a shift register (also called deserializer). The
parallel data is clocked out to the logic array synchronized with the lowfrequency clock. On the transmitter side, the parallel data from the logic
array is first clocked into a parallel-in, serial-out shift register
synchronized with the low-frequency clock and then transmitted out by
the output buffers.
There are four dedicated fast PLLs in EP1S10 to EP1S25 devices, and eight
in EP1S30 to EP1S80 devices. These PLLs are used for the SERDES
operations as well as general-purpose use.
The differential channels and the high-speed PLL layout in Stratix
devices are described in the “Differential I/O Interface & Fast PLLs”
section on page 5–16.
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Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Stratix Differential I/O Receiver Operation
You can configure any of the Stratix differential input channels as a
receiver channel (see Figure 5–3). The differential receiver deserializes
the incoming high-speed data. The input shift register continuously
clocks the incoming data on the negative transition of the high-frequency
clock generated by the PLL clock (×W).
The data in the serial shift register is shifted into a parallel register by the
RXLOADEN signal generated by the fast PLL counter circuitry on the third
falling edge of the high-frequency clock. However, you can select which
falling edge of the high frequency clock loads the data into the parallel
register, using the data-realignment circuit. For more information on the
data-realignment circuit, see “Data Realignment Principles of Operation”
on page 5–25.
In normal mode, the enable signal RXLOADEN loads the parallel data into
the next parallel register on the second rising edge of the low-frequency
clock. You can also load data to the parallel register through the
TXLOADEN signal when using the data-realignment circuit.
Figure 5–3 shows the block diagram of a single SERDES receiver channel.
Figure 5–4 shows the timing relationship between the data and clocks in
Stratix devices in ×10 mode. W is the low-frequency multiplier and J is
data parallelization division factor.
Altera Corporation
July 2005
5–7
Stratix Device Handbook, Volume 2
Principles of SERDES Operation
Figure 5–3. Stratix High-Speed Interface Deserialized in ×10 Mode
Receiver Circuit
Serial Shift
Registers
RXIN+
RXIN−
Parallel
Registers
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
PD8
PD9
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
PD8
PD9
×W
RXCLKIN+
RXCLKIN−
Parallel
Registers
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
PD8
PD9
Stratix
Logic Array
×W/J (1)
Fast RXLOADEN
PLL (2)
TXLOADEN
Notes to Figure 5–3:
(1)
(2)
W = 1, 2, 4, 7, 8, or 10.
J = 4, 7, 8, or 10.
W does not have to equal J. When J = 1 or 2, the deserializer is bypassed. When J = 2, the device uses DDRIO registers.
This figure does not show additional circuitry for clock or data manipulation.
Figure 5–4. Receiver Timing Diagram
Internal ×1 clock
Internal ×10 clock
RXLOADEN
Receiver
data input
n–1
n–0
9
8
7
6
5
4
3
2
1
0
n–1
n–0
9
8
7
6
5
4
3
2
1
0
Internal ×1 clock
Internal ×10 clock
RXLOADEN
Receiver
data input
5–8
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Stratix Differential I/O Transmitter Operation
You can configure any of the Stratix differential output channels as a
transmitter channel. The differential transmitter is used to serialize
outbound parallel data.
The logic array sends parallel data to the SERDES transmitter circuit
when the TXLOADEN signal is asserted. This signal is generated by the
high-speed counter circuitry of the logic array low-frequency clock’s
rising edge. The data is then transferred from the parallel register into the
serial shift register by the TXLOADEN signal on the third rising edge of the
high-frequency clock.
Figure 5–5 shows the block diagram of a single SERDES transmitter
channel and Figure 5–6 shows the timing relationship between the data
and clocks in Stratix devices in ×10 mode. W is the low-frequency
multiplier and J is the data parallelization division factor.
Figure 5–5. Stratix High-Speed Interface Serialized in ×10 Mode
Transmitter Circuit
Stratix
Logic Array
PD9
PD8
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
Parallel
Register
PD9
PD8
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
Serial
Register
TXOUT+
TXOUT−
×W
Fast
PLL
Altera Corporation
July 2005
TXLOADEN
5–9
Stratix Device Handbook, Volume 2
Principles of SERDES Operation
Figure 5–6. Transmitter Timing Diagram
Internal ×1 clock
Internal ×10 clock
TXLOADEN
Receiver
data input
n–1
n–0
9
8
7
6
5
4
3
2
1
0
Transmitter Clock Output
Different applications and protocols call for various clocking schemes.
Some applications require you to center-align the rising or falling clock
edge with the data. Other applications require a divide version of the
transmitted clock, or the clock and data to be at the same high-speed
frequency. The Stratix device transmitter clock output is versatile and
easily programmed for all such applications.
Stratix devices transmit data using the source-synchronous scheme,
where the clock is transmitted along with the serialized data to the
receiving device. Unlike APEXTM 20KE and APEX II devices, Stratix
devices do not have a fixed transmitter clock output pin. The Altera®
Quartus II software generates the transmitter clock output by using a fast
clock to drive a transmitter dataout channel. Therefore, you can place
the transmitter clock pair close to the data channels, reducing clock-todata skew and increasing system margins. This approach is more flexible,
as any channel can drive a clock, not just specially designated clock pins.
Divided-Down Transmitter Clock Output
You can divide down the high-frequency clock by 2, 4, 8, or 10, depending
on the system requirements. The various options allow Stratix devices to
accommodate many different types of protocols. The divided-down clock
is generated by an additional transmitting data channel.
5–10
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Table 5–2 shows the divided-down version of the high-frequency clock
and the selected serialization factor J (described in pervious sections). The
Quartus II software automatically generates the data input to the
additional transmitter data channel.
Table 5–2. Differential Transmitter Output Clock Division
J
Data Input
Output Clock Divided By (1)
4
1010
2
4
0011
4
8
10101010
2
8
00110011
4
8
11000011
8
10
1010101010
2
10
1110000011
10
Note to Table 5–2:
(1)
This value is usually referred to as B.
Center-Aligned Transmitter Clock Output
A negative-edge-triggered D flipflop (DFF) register is located between
the serial register of each data channel and its output buffer, as show in
Figure 5–7. The negative-edge-triggered DFF register is used when
center-aligned data is required. For center alignment, the DFF only shifts
the output from the channel used as the transmitter clock out. The
transmitter data channels bypass the negative-edge DFF. When you use
the DFF register, the data is transmitted at the negative edge of the
multiplied clock. This delays the transmitted clock output relative to the
data channels by half the multiplied clock cycle. This is used for
HyperTransport technology, but can also be used for any interface
requiring center alignment.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Principles of SERDES Operation
Figure 5–7. Stratix Programmable Transmitter Clock
Transmitter Circuit
Stratix
Logic Array
PD9
PD8
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
Parallel
Register
PD9
PD8
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
Serial
Register
TXOUT+
TXOUT−
×W
Fast
PLL
TXLOADEN
SDR Transmitter Clock Output
You can route the high-frequency clock internally generated by the PLL
out as a transmitter clock output on any of the differential channels. The
high-frequency clock output allows Stratix devices to support
applications that require a 1-to-1 relationship between the clock and data.
The path of the high-speed clock is shown in Figure 5–8. A programmable
inverter allows you to drive the signal out on either the negative edge of
the clock or 180º out of phase with the streaming data.
5–12
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Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–8. High-Speed 1-to-1 Transmitter Clock Output
Transmitter Circuit
Stratix
Logic Array
PD9
PD8
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
Parallel
Register
PD9
PD8
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
Serial
Register
Inverter
TXOUT+
TXOUT−
×W
Fast
PLL (1)
TXLOADEN
Note to Figure 5–8:
(1)
This figure does not show additional circuitry for clock or data manipulation.
Using SERDES
to Implement
DDR
Some designs require a 2-to-1 data-to-clock ratio. These systems are
usually based on Rapid I/O, SPI-4 Phase 2 (POS_PHY Level 4), or
HyperTransport interfaces, and support various data rates. Stratix
devices meet this requirement for such applications by providing a
variable clock division factor. The SERDES clock division factor is set to 2
for double data rate (DDR).
An additional differential channel (as described in “Transmitter Clock
Output” on page 5–10) is automatically configured to produce the
transmitter clock output signal with half the frequency of the data.
For example, when a system is required to transmit 6.4 Gbps with a
2-to-1 clock-to-data ratio, program the SERDES with eight high-speed
channels running at 800 Mbps each. When you set the output clock
division factor (2 for this example), the Quartus II software automatically
assigns a ninth channel as the transmitter clock output. You can edge- or
center-align the transmitter clock by selecting the default PLL phase or
selecting the negative-edge transmitter clock output. On the receiver side,
the clock signal is connected to the receiver PLL's clock.
The multiplication factor W is also calculated automatically. The data rate
divides by the input clock frequency to calculate the W factor. The
deserialization factor (J) may be 4, 7, 8, or 10.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Using SERDES to Implement SDR
Figure 5–9 shows a DDR clock-to-data timing relationship with the clock
center-aligned with respect to data. Figure 5–10 shows the connection
between the receiver and transmitter circuits.
Figure 5–9. DDR Clock-to-Data Relationship
inclock
DDR
XX
B0
A0
B1
A1
B2
A2
B3
A3
Figure 5–10. DDR Receiver & Transmitter Circuit Connection
Stratix SERDES DDR Receiver
rx_d[0]
Channel
0
Serial-to-Parallel
Register
Stratix SERDES DDR Transmitter
Parallel
Register
8
8
Parallel
Register
Parallel-to-Serial
Register
Parallel
Register
Parallel-to-Serial
Register
Parallel
Register
Parallel-to-Serial
Register
Channel
0
tx_d[0]
data rate = 800 Mbps
Stratix
Logic
Array
rx_d[15]
data rate = 800 Mbps
Channel
15
Serial-to-Parallel
Register
Parallel
Register
rxclk
LVDS PLL
8
8
input clock × W
400 MHz
8
rxloadena
Channel
15
Channel
16
÷2
txclk_out
800 Mbps
txclk_out
400 MHz
txloaden
LVDS PLL
input clock × W
txclk_in
100 MHz
Using SERDES
to Implement
SDR
Stratix devices support systems based on single data rate (SDR)
operations applications by allowing you to directly transmit out the
multiplied clock (as described in “SDR Transmitter Clock Output” on
page 5–12). These systems are usually based on Utopia-4, SFI-4, or XSBI
interfaces, and support various data rates.
An additional differential channel is automatically configured to produce
the transmitter clock output signal and is transmitted along with the data.
For example, when a system is required to transmit 10 Gbps with a 1-to1 clock-to-data ratio, program the SERDES with sixteen high-speed
channels running at 624 Mbps each. The Quartus II software
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
automatically assigns a seventeenth channel as the transmitter clock
output. You can edge- or center-align the transmitter clock output by
selecting the default PLL phase or selecting the 90° phase of the PLL
output. On the receiver side, the clock signal is connected to the receiver
PLL's clock input, and you can assign identical clock-to-data alignment.
The multiplication factor W is calculated automatically. The data rate is
dividing by the input clock frequency to calculate the W factor. The
deserialization factor J may be 4, 7, 8, or 10.
Figure 5–11 shows an SDR clock-to-data timing relationship, with clock
center aligned with respect to data. Figure 5–12 shows the connection
between the receiver and transmitter circuits.
Figure 5–11. SDR Clock-to-Data Relationship
inclock
SDR
XX
B0
B1
B2
B3
Figure 5–12. SDR Receiver & Transmitter Circuit Connection
Stratix SERDES SDR Receiver
rx_d[0]
Channel
0
Serial-to-Parallel
Register
Stratix SERDES SDR Transmitter
Parallel
Register
8
8
Parallel
Register
Parallel-to-Serial
Register
Parallel
Register
Parallel-to-Serial
Register
Channel
0
tx_d[0]
data rate = 624 Mbps
Stratix
Logic
Array
rx_d[15]
data rate = 624 Mbps
Channel
15
Serial-to-Parallel
Register
Parallel
Register
8
8
input clock × W
Channel
15
Channel
16
txloaden
tx_d[15]
txclk_out
624 MHz
rxclk
624 MHz
LVDS PLL
rxloaden
LVDS PLL
input clock × W
txclk_in
624 MHz
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Differential I/O Interface & Fast PLLs
Differential I/O
Interface & Fast
PLLs
Stratix devices provide 16 dedicated global clocks, 8 dedicated fast
regional I/O pins, and up to 16 regional clocks (four per device quadrant)
that are fed from the dedicated global clock pins or PLL outputs. The 16
dedicated global clocks are driven either by global clock input pins that
support all I/O standards or from enhanced and fast PLL outputs.
Stratix devices use the fast PLLs to implement clock multiplication and
division to support the SERDES circuitry. The input clock is either
multiplied by the W feedback factor and/or divided by the J factor. The
resulting clocks are distributed to SERDES, local, or global clock lines.
Fast PLLs are placed in the center of the left and right sides for EP1S10 to
EP1S25 devices. For EP1S30 to EP1S80 devices, fast PLLs are placed in the
center of the left and right sides, as well as the device corners (see
Figure 5–13). These fast PLLs drive a dedicated clock network to the
SERDES in the rows above and below or top and bottom of the device as
shown in Figure 5–13.
5–16
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–13. Stratix Fast PLL Positions & Clock Naming Convention Note (1)
CLK[15..12]
5
11
FPLLCLK0
7
10
FPLLCLK3
CLK[3..0]
1
2
4
3
CLK[11..8]
8
9
FPLLCLK2
PLLs
FPLLCLK1
6
12
CLK[7..4]
Notes to Figure 5–13:
(1)
(2)
Dedicated clock input pins on the right and left sides do not support PCI or PCI-X 1.0.
PLLs 7, 8, 9, and 10 are not available on the EP1S30 device in the 780-pin FineLine BGA® package.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Differential I/O Interface & Fast PLLs
Clock Input & Fast PLL Output Relationship
Table 5–3 summarizes the PLL interface to the input clocks and the enable
signal (ENA). Table 5–4 summarizes the clock networks each fast PLL can
connect to across all Stratix family devices.
Table 5–3. Fast PLL Clock Inputs (Including Feedback Clocks) & Enables Note (1)
All Stratix Devices
EP1S30 to EP1S80 Devices Only
Input Pin
PLL 1
CLK0 (2)
v
CLK1
v
PLL 2
PLL 3
PLL 4
PLL 7
PLL 8
PLL 9
PLL 10
v (3)
CLK2 (2)
v
CLK3
v
v (3)
CLK4
CLK5
CLK6
CLK7
CLK8
v
CLK9 (2)
v
v (3)
CLK10
v
CLK11 (2)
v
v (3)
CLK12
CLK13
CLK14
CLK15
v
ENA
v
FPLL7CLK
FPLL8CLK
FPLL9CLK
FPLL10CLK
v
v
v
v
v
v
v
v
v
v
Notes to Table 5–3:
(1)
(2)
(3)
PLLs 5, 6, 11, and 12 are not fast PLLs.
Clock pins CLK0, CLK2, CLK9, CLK11, and pins FPLL[7..10]CLK do not support differential on-chip
termination.
Either a FPLLCLK pin or a CLK pin can drive the corner fast PLLs (PLL7, PLL8, PLL9, and PLL10) when used for
general purpose. CLK pins cannot drive these fast PLLs in high-speed differential I/O mode.
5–18
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Table 5–4. Fast PLL Relationship with Stratix Clock Networks (Part 1 of 2) Notes (1), (2)
All Stratix Devices
EP1S30 to EP1S80 Devices Only
Output Signal
PLL 1
GCLK0
v
GCLK1
v
PLL 2
GCLK2
v
GCLK3
v
PLL 3
GCLK4
v
GCLK9
v
PLL 4
GCLK10
v
GCLK11
v
PLL 7
PLL 8
RCLK1
v
v
v
RCLK2
v
v
v
RCLK3
v
v
v
RCLK4
v
v
v
PLL 9
PLL 10
RCLK9
v
v
v
RCLK10
v
v
v
RCLK11
v
v
v
RCLK12
v
v
v
DIFFIOCLK1
v
DIFFIOCLK2
v
DIFFIOCLK3
v
DIFFIOCLK4
v
DIFFIOCLK5
v
DIFFIOCLK6
v
DIFFIOCLK7
v
DIFFIOCLK8
v
DIFFIOCLK9
v
DIFFIOCLK10
v
DIFFIOCLK11
v
DIFFIOCLK12
v
DIFFIOCLK13
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July 2005
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Stratix Device Handbook, Volume 2
Differential I/O Interface & Fast PLLs
Table 5–4. Fast PLL Relationship with Stratix Clock Networks (Part 2 of 2) Notes (1), (2)
All Stratix Devices
EP1S30 to EP1S80 Devices Only
Output Signal
PLL 1
PLL 2
PLL 3
PLL 4
PLL 7
PLL 8
PLL 9
PLL 10
v
DIFFIOCLK14
DIFFIOCLK15
v
DIFFIOCLK16
v
Notes to Table 5–4:
(1)
(2)
PLLs 5, 6, 11, and 12 are not fast PLLs.
The input clock for PLLs used to clock receiver the rx_inclock port on the altlvds_rx megafunction must be
driven by a dedicated clock pin (CLK[3..0] and CLK[8..11]) or the corner pins that clock the corner PLLs
(FPLL[10..7]CLK).
Fast PLL Specifications
You can drive the fast PLLs by an external pin or any one of the sectional
clocks [21..0]. You can connect the clock input directly to local or global
clock lines, as shown in Figure 5–14. You cannot use the sectional-clock
inputs to the fast PLL’s input multiplexer for the receiver PLL. You can
only use the sectional clock inputs in the transmitter only mode or as a
general purpose PLL.
5–20
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–14. Fast PLL Block Diagram
Post-Scale
Counters
DIFFIOCLK1 (1)
÷k
Regional clock
TXLOADEN (2)
VCO Phase Selection
Selectable at each PLL
Output Port
RXLOADEN (2)
÷v
Global or
regional clock
Clock Input
Phase
Frequency
Detector
Charge
Pump
8
Loop
Filter
Regional clock
DIFFIOCLK2 (1)
VCO
÷l
Global or
regional clock
rxclkin
÷m
Notes to Figure 5–14:
(1)
(2)
In high-speed differential I/O mode, the high-speed PLL clock feeds the SERDES. Stratix devices only support one
rate of data transfer per fast PLL in high-speed differential I/O mode.
Control signal for high-speed differential I/O SERDES.
You can multiply the input clock by a factor of 1 to 16. The multiplied
clock is used for high-speed serialization or deserialization operations.
Fast PLL specifications are shown in the Stratix Device Family Data Sheet
section of the Stratix Device Handbook, Volume 1. The voltage controlled
oscillators (VCOs) are designed to operate within the frequency range of
300 to 840 MHz, to provide data rates of up to 840 Mbps.
High-Speed Phase Adjust
There are eight phases of the multiplied clock at the PLL output, each
delayed by 45° from the previous clock and synchronized with the
original clock. The three multiplexers (shown in Figure 5–14) select one of
the delayed, multiplied clocks. The PLL output drives the three counters
k, v, and l. You can program the three individual post scale counters (k, v,
and l) independently for division ratio or phase. The selected PLL output
is used for the serialization or deserialization process in SERDES.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Differential I/O Interface & Fast PLLs
Counter Circuitry
The multiplied clocks bypass the counter taps k and v to directly feed the
SERDES serial registers. These two taps also feed to the quadrant local
clock network and the dedicated RXLOADENA or TXLOADENA pins, as
shown in Figure 5–15. Both k and v are utilized simultaneously during the
data-realignment procedure. When the design does not use the data
realignment, both TXLOADEN and RXLOADEN pins use a single counter.
Figure 5–15. Fast PLL Connection to Logic Array
Counter Circuitry
Post-Scale
Counters
VCO Phase Selection
Selectable at each PLL
Output Port
÷k
CLK1 SERDES
Circuitry
×1 CLK1 to logic array
or local clocks
TXLOADEN
RXLOADEN
8
÷v
PLL Output
Clock
Distribution
Circuitry
×1 CLK2 to logic array
or local clocks
CLK2 SERDES
Circuitry
÷l
Regional clock
clkin
The Stratix device fast PLL has another GCLK connection for generalpurpose applications. The third tap l feeds the quadrant local clock as
well as the global clock network. You can use the l counter's multiplexer
for applications requiring the device to connect the incoming clock
directly to the local or global clocks. You can program the multiplexer to
connect the RXCLKIN signal directly to the local or global clock lines.
Figure 5–15 shows the connection between the incoming clock, the l tap,
and the local or global clock lines.
The differential clock selection is made per differential bank. Since the
length of the clock tree limits the performance, each fast PLL should drive
only one differential bank.
5–22
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Fast PLL SERDES Channel Support
The Quartus II MegaWizard Plug-In Manager only allows you to
implement up to 20 receiver or 20 transmitter channels for each fast PLL.
These channels operate at up to 840 Mbps. For more information on
implementing more than 20 channels, see “Fast PLLs” on page 5–52. The
receiver and transmitter channels are interleaved such that each I/O bank
on the left and right side of the device has one receiver channel and one
transmitter channel per row. Figure 5–16 shows the fast PLL and channel
layout in EP1S10, EP1S20, and EP1S25 devices. Figure 5–17 shows the fast
PLL and channel layout in EP1S30 to EP1S80 devices.
f
For more the number of channels in each device, see Tables 5–10 through
5–14.
Figure 5–16. Fast PLL & Channel Layout in EP1S10, EP1S20 & EP1S25 Devices Note (1)
Up to 20 Receiver and
Transmitter Channels (2)
Transmitter
Up to 20 Receiver and
Transmitter Channels (2)
Transmitter
Receiver
Receiver
CLKIN
Fast
PLL 1
CLKIN
Fast
PLL 2
(3)
Transmitter
Receiver
Up to 20 Receiver and
Transmitter Channels (2)
Fast
PLL 4
CLKIN
Fast
PLL 3
CLKIN
(3)
Transmitter
Receiver
Up to 20 Receiver and
Transmitter Channels (2)
Notes to Figure 5–16:
(1)
(2)
(3)
Wire-bond packages only support up to 624 Mbps until characterization shows otherwise.
See Tables 5–10 through 5–14 for the exact number of channels each package and device density supports.
There is a multiplexer here to select the PLL clock source. If a PLL uses this multiplexer to clock channels outside of
its bank quadrant (e.g., if PLL 2 clocks PLL 1’s channel region), those clocked channels support up to 840 Mbps.
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July 2005
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Stratix Device Handbook, Volume 2
Differential I/O Interface & Fast PLLs
Figure 5–17. Fast PLL & Channel Layout in EP1S30 to EP1S80 Devices Note (1)
FPLL7CLK
Fast
PLL 7
Fast
PLL 10
Up to 20 Receiver and
20 Transmitter
Channels in 20 Rows (2)
Transmitter
FPLL10CLK
Transmitter
Receiver
Receiver
Up to 20 Receiver and
20 Transmitter
Channels in 20 Rows (2)
Transmitter
Transmitter
Receiver
CLKIN
CLKIN
Receiver
Fast
PLL 1
(3)
(3)
Fast
PLL 2
Fast
PLL 4
CLKIN
Fast
PLL 3
CLKIN
Transmitter
Transmitter
Receiver
Receiver
Up to 20 Receiver and
20 Transmitter
Channels in 20 Rows (2)
Transmitter
Transmitter
Receiver
FPLL8CLK
Receiver
Fast
PLL 8
Up to 20 Receiver and
20 Transmitter
Channels in 20 Rows (2)
Fast
PLL 9
FPLL9CLK
Notes to Figure 5–17:
(1)
(2)
(3)
Wire-bond packages only support up to 624-Mbps until characterization shows otherwise.
See Tables 5–10 through 5–14 for the exact number of channels each package and device density supports.
There is a multiplexer here to select the PLL clock source. If a PLL uses this multiplexer to clock channels outside of
its bank quadrant (e.g., if PLL 2 clocks PLL 1’s channel region), those clocked channels support up to 840 Mbps.
5–24
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Advanced Clear & Enable Control
There are several control signals for clearing and enabling PLLs and their
outputs. You can use these signals to control PLL resynchronization and
to gate PLL output clocks for low-power applications.
The PLLENABLE pin is a dedicated pin that enables and disables Stratix
device enhanced and fast PLLs. When the PLLENABLE pin is low, the
clock output ports are driven by GND and all the PLLs go out of lock.
When the PLLENABLE pin goes high again, the PLLs relock and
resynchronize to the input clocks.
The reset signals are reset/resynchronization inputs for each enhanced
PLL. Stratix devices can drive these input signals from an input pin or
from LEs. When driven high, the PLL counters reset, clearing the PLL
output and placing the PLL out of lock. When driven low again, the PLL
resynchronizes to its input as it relocks.
Receiver Data
Realignment
Most systems using serial differential I/O data transmission require a
certain data-realignment circuit. Stratix devices contain embedded datarealignment circuitry. While normal I/O operation guarantees that data
is captured, it does not guarantee the parallelization boundary, as this
point is randomly determined based on the power-up of both
communicating devices. The data-realignment circuitry corrects for bit
misalignments by shifting, or delaying, data bits.
Data Realignment Principles of Operation
Stratix devices use a realignment and clock distribution circuitry
(described in “Counter Circuitry” on page 5–22) for data realignment.
Set the internal rx_data_align node end high to assert the datarealignment circuitry. When this node is switched from a low to a high
state, the realignment circuitry is activated and the data is delayed by one
bit. To ensure the rising edge of the rx_data_align node end is latched
into the PLL, the rx_data_align node end should stay high for at least
two low-frequency clock cycles.
An external circuit or an internal custom-made state machine using LEs
can generate the signal to pull the rx_data_align node end to a high
state.
When the data realignment circuitry is activated, it generates an internal
pulse Sync S1 or Sync S2 that disables one of the two counters used for the
SERDES operation (described in “Counter Circuitry” on page 5–22). One
counter is disabled for one high-frequency clock cycle, delaying the
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July 2005
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Stratix Device Handbook, Volume 2
Receiver Data Realignment
RXLOADEN signal and dropping the first incoming bit of the serial input
data stream located in the first serial register of the SERDES circuitry
(shown in Figure 5–3 on page 5–8).
Figure 5–18 shows the function-timing diagram of a Stratix SERDES in
normal ×8 mode, and Figure 5–19 shows the function-timing diagrams of
a Stratix SERDES when data realignment is used.
Figure 5–18. SERDES Function Timing Diagram in Normal Operation
×8 clock
Serial data
D7
D0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
×1 clock
PD7
D2
D2
D2
PD6
D3
D3
D3
PD5
D4
D4
D4
PD4
D5
D5
D5
PD3
D6
D6
D6
PD2
D7
D7
D7
PD1
D0
D0
D0
PD0
D1
D1
D1
5–26
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–19. SERDES Function Timing Diagram with Data-Realignment Operation
×8 clock
Serial data
D7
D0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
×1 clock
PD7
D2
D3
D3
PD6
D3
D4
D4
PD5
D4
D5
D5
PD4
D5
D6
D6
PD3
D6
D7
D7
PD2
D7
D0
D0
PD1
D0
D1
D1
PD0
D1
D2
D2
Generating the TXLOADEN Signal
The TXLOADEN signal controls the transfer of data between the SERDES
circuitry and the logic array when data realignment is used. To prevent
the interruption of the TXLOADEN signal during data realignment, both k
and v counter are used.
In normal operation the TXLOADEN signal is generated by the k counter.
However, during the data-realignment operation this signal is generated
by either counter. When the k counter is used for realignment, the
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July 2005
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Stratix Device Handbook, Volume 2
Receiver Data Realignment
TXLOADEN signal is generated by the v counter, and when the v counter
is used for realignment, the TXLOADEN signal is generated by the k
counter, as shown in Figure 5–20.
Figure 5–20. Realignment Circuit TXLOADEN Signal Control Note (1)
Counter Circuitry
Clock
Distribution
Circuitry
CLK1 LVDS
Circuitry
×1 CLK1 to logic array
÷k
TXLOADEN
Sync S1
Data
Realignment
Circuit
Realignment CLK
8
PLL Output
SYNC
Realignment CLK
Data
Realignment
Circuit
Sync S2
RXLOADEN
÷v
×1 CLK2 to logic array
CLK2 LVDS
Circuitry
÷l
GCLK/LCLK
Note to Figure 5–20:
(1)
This figure does not show additional realignment circuitry.
Realignment Implementation
The realignment signal (SYNC) is used for data realignment and
reframing. An external pin (RX_DATA_ALIGN) or an internal signal
controls the rx_data_align node end. When the rx_data_align
node end is asserted high for at least two low-frequency clock cycles, the
RXLOADEN signal is delayed by one high-frequency clock period and the
parallel bits shift by one bit. Figure 5–21 shows the timing relationship
between the high-frequency clock, the RXLOADEN signal, and the parallel
data.
5–28
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–21. Realignment by rx_data_align Node End
10× clock
1× clock
SYNC
rxloaden
6
datain
receiver A
receiver B
5
7
6
8
7
9
8
0
9
1
0
2
1
3
2
0123456789
4
3
5
4
6
5
7
6
8
7
9
8
0
9
1
0
2
1
0123456789
3
2
4
3
5
4
6
5
7
6
8
7
9
8
0
9
1
0
1234567890
2
1
3
2
4
3
4
1234567890
A state machine can generate the realignment signal to control the
alignment procedure. Figure 5–22 shows the connection between the
realignment signal and the rx_data_align node end.
Figure 5–22. SYNC Signal Path to Realignment Circuit
Stratix Logic Array
Receiver Circuit
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
PD8
PD9
Parallel
Register
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
PD8
PD9
Register
Array
SYNC Out
10
Pattern
Detection
State Machine
Hold
Register
TXLOADEN
×1
×W/J
Realignment
Circuit
SYNC
To guarantee that the rx_data_align signal generated by a user state
machine is latched correctly by the counters, the user circuit must meet
certain requirements.
■
Altera Corporation
July 2005
The design must include an input synchronizing register to ensure
that data is synchronized to the ×1 clock.
5–29
Stratix Device Handbook, Volume 2
Source-Synchronous Timing Budget
■
■
■
■
SourceSynchronous
Timing Budget
After the pattern detection state machine, use another synchronizing
register to capture the generated SYNC signal and synchronize it to
the ×1 clock.
Since the skew in the path from the output of this synchronizing
register to the PLL is undefined, the state machine must generate a
pulse that is high for two ×1 clock periods.
Since the SYNC generator circuitry only generates a single fast clock
period pulse for each SYNC pulse, you cannot generate additional
SYNC pulses until the comparator signal is reset low.
To guarantee the pattern detection state machine does not incorrectly
generate multiple SYNC pulses to shift a single bit, the state machine
must hold the SYNC signal low for at least three ×1 clock periods
between pulses.
This section discusses the timing budget, waveforms, and specifications
for source-synchronous signaling in Stratix devices. LVDS, LVPECL,
PCML, and HyperTransport I/O standards enable high-speed data
transmission. This high data-transmission rate results in better overall
system performance. To take advantage of fast system performance, you
must understand how to analyze timing for these high-speed signals.
Timing analysis for the differential block is different from traditional
synchronous timing analysis techniques.
Rather than focusing on clock-to-output and setup times, sourcesynchronous timing analysis is based on the skew between the data and
the clock signals. High-speed differential data transmission requires you
to use timing parameters provided by IC vendors and to consider board
skew, cable skew, and clock jitter. This section defines the sourcesynchronous differential data orientation timing parameters, and timing
budget definitions for Stratix devices, and explains how to use these
timing parameters to determine a design's maximum performance.
Differential Data Orientation
There is a set relationship between an external clock and the incoming
data. For operation at 840 Mbps and W = 10, the external clock is
multiplied by 10 and phase-aligned by the PLL to coincide with the
sampling window of each data bit. The third falling edge of highfrequency clock is used to strobe the incoming high-speed data.
Therefore, the first two bits belong to the previous cycle. Figure 5–23
shows the data bit orientation of the ×10 mode as defined in the
Quartus II software.
5–30
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–23. Bit Orientation in the Quartus II Software
inclock/outclock
10 LVDS Bits
MSB
data in
n-1
n-0
9
8
7
6
5
4
LSB
3
2
1
0
high-frequency clock
Differential I/O Bit Position
Data synchronization is necessary for successful data transmission at
high frequencies. Figure 5–24 shows the data bit orientation for a receiver
channel operating in ×8 mode. Similar positioning exists for the most
significant bits (MSBs) and least significant bits (LSBs) after
deserialization, as listed in Table 5–5.
Figure 5–24. Bit Order for One Channel of Differential Data
inclock/outclock
Previous Cycle
Data in/
Data out
Current Cycle
D7
MSB
D6
D5
0
0
D4
D3
Next Cycle
D2
D1
D0
LSB
1
0
Example: Sending the Data 10010110
Previous Cycle
Data in/
Data out
Current Cycle
1
MSB
Altera Corporation
July 2005
1
0
Next Cycle
1
LSB
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Stratix Device Handbook, Volume 2
Source-Synchronous Timing Budget
Table 5–5 shows the conventions for differential bit naming for
18 differential channels. However, the MSB and LSB are increased with
the number of channels used in a system.
Table 5–5. LVDS Bit Naming
Receiver Data Channel
Number
Internal 8-Bit Parallel Data
MSB Position
LSB Position
1
7
0
2
15
8
3
23
16
4
31
24
5
39
32
6
47
40
7
55
48
8
63
56
9
71
64
10
79
72
11
87
80
12
95
88
13
103
96
14
111
104
15
119
112
16
127
120
17
135
128
18
143
136
Timing Definition
The specifications used to define high-speed timing are described in
Table 5–6.
Table 5–6. High-Speed Timing Specifications & Terminology (Part 1 of 2)
High-Speed Timing Specification
Terminology
tC
High-speed receiver/transmitter input and output clock period.
fHSCLK
High-speed receiver/transmitter input and output clock frequency.
tRISE
Low-to-high transmission time.
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July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Table 5–6. High-Speed Timing Specifications & Terminology (Part 2 of 2)
High-Speed Timing Specification
Terminology
tFALL
High-to-low transmission time.
Timing unit interval (TUI)
The timing budget allowed for skew, propagation delays, and data
sampling window. (TUI = 1/(Receiver Input Clock Frequency ×
Multiplication Factor) = tC/w).
fHSDR
Maximum LVDS data transfer rate (fHSDR = 1/TUI).
Channel-to-channel skew (TCCS)
The timing difference between the fastest and slowest output edges,
including tCO variation and clock skew. The clock is included in the TCCS
measurement.
Sampling window (SW)
The period of time during which the data must be valid in order for you to
capture it correctly. The setup and hold times determine the ideal strobe
position within the sampling window.
SW = tSW (max) – tSW (min).
Input jitter (peak-to-peak)
Peak-to-peak input jitter on high-speed PLLs.
Output jitter (peak-to-peak)
Peak-to-peak output jitter on high-speed PLLs.
tDUTY
Duty cycle on high-speed transmitter output clock.
tLOCK
Lock time for high-speed transmitter and receiver PLLs.
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July 2005
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Stratix Device Handbook, Volume 2
Table 5–7. High-Speed I/O Specifications for Flip-Chip Packages (Part 1 of 3) Notes (1), (2)
-5 Speed Grade
Symbol
fHSDR Device
operation
(LVDS, LVPECL,
HyperTransport
technology)
5–34
Stratix Device Handbook, Volume 2
fHSCLK (Clock
frequency)
(PCML)
fHSCLK = fHSDR / W
-7 Speed Grade
-8 Speed Grade
Unit
Min
fHSCLK (Clock
frequency)
(LVDS, LVPECL,
HyperTransport
technology)
fHSCLK = fHSDR / W
-6 Speed Grade
Conditions
Typ
Max
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
W = 4 to 30
10
210
10
210
10
156
10
115.5
MHz
W = 2 (Serdes
bypass)
50
231
50
231
50
231
50
231
MHz
W = 2 (Serdes used)
150
420
150
420
150
312
150
231
MHz
W = 1 (Serdes
bypass)
100
462
100
462
100
462
100
462
MHz
W = 1 (Serdes used)
300
717
300
717
300
624
300
462
MHz
J = 10
300
840
300
840
300
640
300
462
Mbps
J=8
300
840
300
840
300
640
300
462
Mbps
J=7
300
840
300
840
300
640
300
462
Mbps
J=4
300
840
300
840
300
640
300
462
Mbps
J=2
100
462
100
462
100
640
100
462
Mbps
J = 1 (LVDS and
LVPECL only)
100
462
100
462
100
640
100
462
Mbps
W = 4 to 30 (Serdes
used)
10
100
10
100
10
77.75
10
77.75
MHz
W = 2 (Serdes
bypass)
50
200
50
200
50
150
50
150
MHz
W = 2 (Serdes used)
150
200
150
200
150
155.5
150
155.5
MHz
W = 1 (Serdes
bypass)
100
250
100
250
100
200
100
200
MHz
W = 1 (Serdes used)
300
400
300
400
300
311
300
311
MHz
Source-Synchronous Timing Budget
Altera Corporation
July 2005
Tables 5–7 and 5–8 show the high-speed I/O timing for Stratix devices
-5 Speed Grade
Symbol
-7 Speed Grade
-8 Speed Grade
Unit
Min
fHSDR Device
operation (PCML)
-6 Speed Grade
Conditions
Typ
Max
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
J = 10
300
400
300
400
300
311
300
311
Mbps
J=8
300
400
300
400
300
311
300
311
Mbps
J=7
300
400
300
400
300
311
300
311
Mbps
J=4
300
400
300
400
300
311
300
311
Mbps
J=2
100
400
100
400
100
300
100
300
Mbps
J=1
100
250
100
250
100
200
100
200
Mbps
300
ps
TCCS
All
SW
PCML (J = 4, 7, 8,
10)
200
750
200
300
750
800
800
ps
5–35
Stratix Device Handbook, Volume 2
PCML (J = 2)
900
900
1,200
1,200
ps
PCML (J = 1)
1,500
1,500
1,700
1,700
ps
LVDS and LVPECL
(J = 1)
500
500
550
550
ps
LVDS, LVPECL,
HyperTransport
technology (J = 2
through 10)
440
440
500
500
ps
Input jitter tolerance All
(peak-to-peak)
250
250
250
250
ps
Output jitter (peakto-peak)
All
160
160
200
200
ps
Output tRISE
LVDS
80
110
120
80
110
120
80
110
120
80
110
120
ps
HyperTransport
technology
110
170
200
110
170
200
120
170
200
120
170
200
ps
LVPECL
90
130
150
90
130
150
100
135
150
100
135
150
ps
PCML
80
110
135
80
110
135
80
110
135
80
110
135
ps
Source-Synchronous Timing Budget
Altera Corporation
July 2005
Table 5–7. High-Speed I/O Specifications for Flip-Chip Packages (Part 2 of 3) Notes (1), (2)
-5 Speed Grade
Symbol
Output tFALL
tDUTY
-7 Speed Grade
-8 Speed Grade
Unit
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
LVDS
80
110
120
80
110
120
80
110
120
80
110
120
ps
HyperTransport
technology
110
170
200
110
170
200
110
170
200
110
170
200
ps
LVPECL
90
130
160
90
130
160
100
135
160
100
135
160
ps
PCML
105
140
175
105
140
175
110
145
175
110
145
175
ps
LVDS (J = 2 through
10)
47.5
50
52.5
47.5
50
52.5
47.5
50
52.5
47.5
50
52.5
%
45
50
55
45
50
55
45
50
55
45
50
55
%
100
μs
LVDS (J =1) and
LVPECL, PCML,
HyperTransport
technology
tLOCK
-6 Speed Grade
Conditions
All
100
100
100
Notes to Table 5–7:
(1)
(2)
When J = 4, 7, 8, and 10, the SERDES block is used.
When J = 2 or J = 1, the SERDES is bypassed.
Table 5–8. High-Speed I/O Specifications for Wire-Bond Packages (Part 1 of 3)
-6 Speed Grade
Symbol
-8 Speed Grade
Unit
Min
Altera Corporation
July 2005
fHSCLK (Clock frequency)
(LVDS,LVPECL, HyperTransport
technology)
fHSCLK = fHSDR / W
-7 Speed Grade
Conditions
W = 4 to 30 (Serdes used)
10
Typ
Max
Min
156
Typ
Max
Min
Typ
Max
10
115.5
10
115.5
MHz
W = 2 (Serdes bypass)
50
231
50
231
50
231
MHz
W = 2 (Serdes used)
150
312
150
231
150
231
MHz
W = 1 (Serdes bypass)
100
311
100
270
100
270
MHz
W = 1 (Serdes used)
300
624
300
462
300
462
MHz
Source-Synchronous Timing Budget
5–36
Stratix Device Handbook, Volume 2
Table 5–7. High-Speed I/O Specifications for Flip-Chip Packages (Part 3 of 3) Notes (1), (2)
-6 Speed Grade
Symbol
fH S C L K (Clock frequency)
(PCML)
fHSCLK = fHSDR / W
Device operation, fH S D R
(PCML)
-8 Speed Grade
Unit
Min
fHSDR Device operation,
(LVDS,LVPECL, HyperTransport
technology)
-7 Speed Grade
Conditions
Typ
Max
Min
Typ
Max
Min
Typ
Max
J = 10
300
624
300
462
300
462
Mbps
J=8
300
624
300
462
300
462
Mbps
J=7
300
624
300
462
300
462
Mbps
J=4
300
624
300
462
300
462
Mbps
J=2
100
462
100
462
100
462
Mbps
J = 1 (LVDS and LVPECL only)
100
311
100
270
100
270
Mbps
W = 4 to 30 (Serdes used)
10
77.75
W = 2 (Serdes bypass)
50
150
W = 2 (Serdes used)
150
155.5
W = 1 (Serdes bypass)
100
200
W = 1 (Serdes used)
300
311
MHz
50
77.5
50
77.5
MHz
MHz
100
155
100
155
MHz
MHz
5–37
Stratix Device Handbook, Volume 2
J = 10
300
311
Mbps
J=8
300
311
Mbps
J=7
300
311
Mbps
J=4
300
311
Mbps
J=2
100
300
100
155
100
155
Mbps
J=1
100
200
100
155
100
155
Mbps
TCCS
All
SW
PCML (J = 4, 7, 8, 10) only
400
400
400
ps
800
800
800
ps
PCML (J = 2) only
1,200
1,200
1,200
ps
PCML (J = 1) only
1,700
1,700
1,700
ps
LVDS and LVPECL (J = 1) only
550
550
550
ps
LVDS, LVPECL, HyperTransport
technology (J = 2 through 10) only
500
500
500
ps
Source-Synchronous Timing Budget
Altera Corporation
July 2005
Table 5–8. High-Speed I/O Specifications for Wire-Bond Packages (Part 2 of 3)
-6 Speed Grade
Symbol
-7 Speed Grade
-8 Speed Grade
Conditions
Unit
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
Input jitter tolerance (peak-topeak)
All
250
250
250
ps
Output jitter (peak-to-peak)
All
200
200
200
ps
Output tR I S E
LVDS
80
110
120
80
110
120
80
110
120
ps
HyperTransport technology
120
170
200
120
170
200
120
170
200
ps
LVPECL
100
135
150
100
135
150
100
135
150
ps
PCML
80
110
135
80
110
135
80
110
135
ps
Output tFA L L
tD U T Y
LVDS
80
110
120
80
110
120
80
110
120
ps
HyperTransport
110
170
200
110
170
200
110
170
200
ps
LVPECL
100
135
160
100
135
160
100
135
160
ps
PCML
110
145
175
110
145
175
110
145
175
ps
LVDS (J =2..10) only
47.5
50
52.5
47.5
50
52.5
47.5
50
52.5
%
45
50
55
45
50
55
45
50
55
%
100
μs
LVDS (J =1) and LVPECL, PCML,
HyperTransport technology
tL O C K
All
100
100
Source-Synchronous Timing Budget
Altera Corporation
July 2005
Table 5–8. High-Speed I/O Specifications for Wire-Bond Packages (Part 3 of 3)
5–38
Stratix Device Handbook, Volume 2
High-Speed Differential I/O Interfaces in Stratix Devices
Input Timing Waveform
Figure 5–25 illustrates the essential operations and the timing
relationship between the clock cycle and the incoming serial data. For a
functional description of the SERDES, see “Principles of SERDES
Operation” on page 5–6.
Figure 5–25. Input Timing Waveform Note (1)
Input Clock
(Differential
Signal)
Previous Cycle
bit 0
Input Data
Next
Cycle
Current Cycle
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
tsw0 (min)
MSB
tsw0 (max)
tsw1 (min)
tsw1 (max)
tsw2 (min)
tsw2 (max)
tsw3 (min)
tsw3 (max)
tsw4 (min)
tsw4 (max)
tsw5 (min)
tsw5 (max)
tsw6 (min)
tsw6 (max)
tsw7 (min)
tsw7 (max)
bit 7
LSB
Note to Figure 5–25:
(1)
The timing specifications are referenced at a 100-mV differential voltage.
Altera Corporation
July 2005
5–39
Stratix Device Handbook, Volume 2
Source-Synchronous Timing Budget
Output Timing
The output timing waveform in Figure 5–26 illustrates the relationship
between the output clock and the serial output data stream.
Figure 5–26. Output Timing Waveform Note (1)
Output Clock
(Differential
Signal)
Previous Cycle
Output Data
bit 0
Next
Cycle
Current Cycle
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
TPPos0 (min)
MSB
TPPos0 (max)
LSB
TPPos1 (min)
TPPos1 (max)
TPPos2 (min)
TPPos2 (max)
TPPos3 (min)
TPPos3 (max)
TPPos4 (min)
TPPos4 (max)
TPPos5 (min)
TPPos5 (max)
TPPos6 (min)
TPPos6 (max)
TPPos7 (min)
TPPos7 (max)
Note to Figure 5–26:
(1)
The timing specifications are referenced at a 250-mV differential voltage.
Receiver Skew Margin
Change in system environment, such as temperature, media (cable,
connector, or PCB) loading effect, a receiver's inherent setup and hold,
and internal skew, reduces the sampling window for the receiver. The
timing margin between receiver’s clock input and the data input
sampling window is known as RSKM. Figure 5–27 illustrates the
relationship between the parameter and the receiver’s sampling window.
5–40
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–27. Differential High-Speed Timing Diagram & Timing Budget
Timing Diagram
External
Input Clock
Time Unit Interval (TUI)
Internal
Clock
TCCS
TCCS
Receiver
Input Clock
Sampling
Window (SW)
RSKM
RSKM
TPPos (max)
Bit n + 1
TPPos (max)
Bit n
tSW (min)
Bit n
TPPos (min)
Bit n
Timing Budget
Internal tSW (max)
Clock
Bit n
Falling Edge
TPPos (min)
Bit n + 1
TUI
External
Clock
Clock Placement
Internal
Clock
Synchronization
Transmitter
Output Data
RSKM
RSKM
TCCS
TCCS
2
TSWEND
Receiver
Input Data
TSWBEGIN
Altera Corporation
July 2005
Sampling
Window
5–41
Stratix Device Handbook, Volume 2
SERDES Bypass DDR Differential Signaling
Switching Characteristics
Timing specifications for Stratix devices are listed in Tables 5–7 and 5–8.
You can also find Stratix device timing information in the Stratix Device
Family Data Sheet section of the Stratix Device Handbook, Volume 1.
Timing Analysis
Differential timing analysis is based on skew between data and the clock
signals. For static timing analysis, the timing characteristics of the
differential I/O standards are guaranteed by design and depend on the
frequency at which they are operated. Use the values in the Stratix Device
Family Data Sheet section of the Stratix Device Handbook, Volume 1 to
calculate system timing margins for various I/O protocols. For detailed
descriptions and implementations of these protocols, see the Altera web
site at www.altera.com.
SERDES Bypass
DDR Differential
Signaling
Each Stratix device high-speed differential I/O channel can transmit or
receive data in by-two (×2) mode at up to 624 Mbps using PLLs. These
pins do not require dedicated SERDES circuitry and they implement
serialization and deserialization with minimal logic.
SERDES Bypass DDR Differential Interface Review
Stratix devices use dedicated DDR circuitry to implement ×2 differential
signaling. Although SDR circuitry samples data only at the positive edge
of the clock, DDR captures data on both the rising and falling edges for
twice the transfer rate of SDR. Stratix device shift registers, internal global
PLLs, and I/O cells can perform serial-to-parallel conversions on
incoming data and parallel-to-serial conversion on outgoing data.
SERDES Clock Domains
The SERDES bypass differential signaling can use any of the many clock
domains available in Stratix devices. These clock domains fall into four
categories: global, regional, fast regional, and internally generated.
General-purpose PLLs generate the global clock domains. The fast PLLs
can generate additional global clocks domains. Each PLL features two
taps that directly drive two unique global clock networks. A dedicated
clock pin drives each general-purpose PLL. These clock lines are utilized
when designing for speeds up to 420 Mbps. Tables 5–3 and 5–4 on
page 5–19, respectively, show the available clocks in Stratix devices.
5–42
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
SERDES Bypass DDR Differential Signaling Receiver Operation
The SERDES bypass differential signaling receiver uses the Stratix device
DDR input circuitry to receive high-speed serial data. The DDR input
circuitry consists of a pair of shift registers used to capture the high-speed
serial data, and a latch.
One register captures the data on the positive edge of the clock (generated
by PLL) and the other register captures the data on the negative edge of
the clock. Because the data captured on the negative edge is delayed by
one-half of the clock cycle, it is latched before it interfaces with the system
logic.
Figure 5–28 shows the DDR timing relationship between the incoming
serial data and the clock. In this example, the inclock signal is running
at half the speed of the incoming data. However, other combinations are
also possible. Figure 5–29 shows the DDR input and the other modules
used in a Flexible-LVDS receiver design to interface with the system logic.
Figure 5–28. ×2 Timing Relation between Incoming Serial Data & Clock
clock
datain
B0
neg_reg_out XX
Altera Corporation
July 2005
A0
B1
B0
A1
B2
B1
A2
B3
B2
A3
B3
dataout_l
XX
B0
B1
B2
dataout_h
XX
A0
A1
A2
5–43
Stratix Device Handbook, Volume 2
SERDES Bypass DDR Differential Signaling
Figure 5–29. ×2 Data Rate Receiver Channel with Deserialization Factor of 8
DDR IOE
datain
Shift
Register
DFF
D0, D2, D4, D6
Register
D1, D3, D5, D7
Stratix
Logic
Array
Latch
DFF
Shift
Register
inclock
PLL
×4
Clock
×1
SERDES Bypass DDR Differential Signaling Transmitter
Operation
The ×2 differential signaling transmitter uses the Stratix device DDR
output circuitry to transmit high-speed serial data. The DDR output
circuitry consists of a pair of shift registers and a multiplexer. The shift
registers capture the parallel data on the clock’s rising edge (generated by
the PLL), and a multiplexer transmits the data in sync with the clock.
Figure 5–30 shows the DDR timing relation between the parallel data and
the clock. In this example, the inclock signal is running at half the speed
of the data. However, other combinations are possible. Figure 5–31 shows
the DDR output and the other modules used in a ×2 transmitter design to
interface with the system logic.
5–44
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–30. ×2 Timing Relation between Parallel Data & Clock
outclock
datain_l XX
B0
B1
B2
B3
datain_h XX
A0
A1
A2
A3
dataout
XX
A0
B0
A1
B1
A2
B2
A3
Figure 5–31. ×2 Data Rate Transmitter Channel with Serialization Factor of 8
DDR IOE
DFF
D0, D2,
D4, D6
Stratix
Logic
Array
Shift
Register
dataout
DFF
D1, D3,
D5, D7
Shift
Register
×1
PLL
×4
×1
inclock
High-Speed
Interface Pin
Locations
Stratix high-speed interface pins are located at the edge of the package to
limit the possible mismatch between a pair of high-speed signals. Stratix
devices have eight programmable I/O banks. Figure 5–32 shows the I/O
pins and their location relative to the package.
Altera Corporation
July 2005
5–45
Stratix Device Handbook, Volume 2
Differential I/O Termination
Figure 5–32. Differential I/O Pin Locations
Differential I/O Pins
(LVDS, LVPECL,
PCML, HyperTransport)
Regular I/O Pins
Differential I/O Pins
(LVDS, LVPECL,
PCML, HyperTransport)
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
T
U
V
W
Y
AA
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Regular I/O Pins
Differential I/O
Termination
Stratix devices implement differential on-chip termination to reduce
reflections and maintain signal integrity. On-chip termination also
minimizes the number of external resistors required. This simplifies
board design and places the resistors closer to the package, eliminating
small stubs that can still lead to reflections.
RD Differential Termination
Stratix devices support differential on-chip termination for the LVDS I/O
standard. External termination is required on output pins for PCML
transmitters. HyperTransport, LVPECL, and LVDS receivers require
100 ohm termination at the input pins. Figure 5–33 shows the device with
differential termination for the LVDS I/O standard.
f
For more information on differential on-chip termination technology, see
the Selectable I/O Standards in Stratix & Stratix GX Devices chapter.
5–46
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–33. LVDS Differential On-Chip Termination
LVDS Receiver with
On-Chip 100-Ω Termination
LVDS Transmitter
Z0 = 50 Ω
RD
Z0 = 50 Ω
HyperTransport & LVPECL Differential Termination
HyperTransport and LVPECL I/O standards are terminated by an
external 100-Ω resistor on the input pin. Figure 5–34 shows the device
with differential termination for the HyperTransport or LVPECL I/O
standard.
Figure 5–34. HyperTransport & LVPECL Differential Termination
Differential
Transmitter
Differential Receiver
Z0 = 50 Ω
RD
Z0 = 50 Ω
PCML Differential Termination
The PCML I/O technology is an alternative to the LVDS I/O technology,
and use an external voltage source (VTT), a pair of 100-Ω resistors on the
input side and a pair of 50-Ω resistors on the output side. Figure 5–35
shows the device with differential termination for PCML I/O standard.
Altera Corporation
July 2005
5–47
Stratix Device Handbook, Volume 2
Differential I/O Termination
Figure 5–35. PCML Differential Termination
VTT
Differential
Transmitter
50 Ω
50 Ω
50 Ω
Differential
Receiver
50 Ω
Z0 = 50 Ω
Z0 = 50 Ω
Differential HSTL Termination
The HSTL Class I and II I/O standards require a 0.75-V VREF and a 0.75V VTT. Figures 5–36 and 5–37 show the device with differential
termination for HSTL Class I and II I/O standard.
Figure 5–36. Differential HSTL Class I Termination
VTT = 0.75 V
Differential
Transmitter
50 Ω
VTT = 0.75 V
50 Ω
Differential
Receiver
Z0 = 50 Ω
Z0 = 50 Ω
5–48
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–37. Differential HSTL Class II Termination
VTT = 0.75 V
Differential
Transmitter
50 Ω
VTT = 0.75 V
VTT = 0.75 V
50 Ω
50 Ω
VTT = 0.75 V
Differential
Receiver
50 Ω
Z0 = 50 Ω
Z0 = 50 Ω
Differential SSTL-2 Termination
The SSTL-2 Class I and II I/O standards require a 1.25-V VREF and a
1.25-V VTT. Figures 5–37 and 5–38 show the device with differential
termination for SSTL-2 Class I and II I/O standard.
Figure 5–38. Differential SSTL-2 Class I Termination
VTT = 1.25 V
Differential
Transmitter
50 Ω
VTT = 1.25 V
50 Ω
Differential
Receiver
25 Ω
Z0 = 50 Ω
25 Ω
Z0 = 50 Ω
Altera Corporation
July 2005
5–49
Stratix Device Handbook, Volume 2
Board Design Consideration
Figure 5–39. Differential SSTL-2 Class II Termination
VTT = 1.25 V
Differential
Transmitter
50 Ω
VTT = 1.25 V
50 Ω
VTT = 1.25 V
50 Ω
VTT = 1.25 V
50 Ω
Differential
Receiver
25 Ω
Z0 = 50 Ω
25 Ω
Z0 = 50 Ω
Board Design
Consideration
This section is a brief explanation of how to get the optimal performance
from the Stratix high-speed I/O block and ensure first-time success in
implementing a functional design with optimal signal quality. For more
information on detailed board layout recommendation and I/O pin
terminations see AN 224: High-Speed Board Layout Guidelines.
You must consider the critical issues of controlled impedance of traces
and connectors, differential routing, and termination techniques to get
the best performance from the IC. For more information, use this chapter
and the Stratix Device Family Data Sheet section of the Stratix Device
Handbook, Volume 1.
The Stratix high-speed module generates signals that travel over the
media at frequencies as high as 840 Mbps. Board designers should use the
following general guidelines:
■
■
■
■
■
■
■
Baseboard designs on controlled differential impedance. Calculate
and compare all parameters such as trace width, trace thickness, and
the distance between two differential traces.
Place external reference resistors as close to receiver input pins as
possible.
Use surface mount components.
Avoid 90° or 45° corners.
Use high-performance connectors such as HS-3 connectors for
backplane designs. High-performance connectors are provided by
Teradyne Corp (www.teradyne.com) or Tyco International Ltd.
(www.tyco.com).
Design backplane and card traces so that trace impedance matches
the connector’s and/or the termination’s impedance.
Keep equal number of vias for both signal traces.
5–50
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
■
■
■
■
■
Software
Support
Create equal trace lengths to avoid skew between signals. Unequal
trace lengths also result in misplaced crossing points and system
margins as the TCCS value increases.
Limit vias because they cause discontinuities.
Use the common bypass capacitor values such as 0.001 µF, 0.01 µF,
and 0.1 µF to decouple the fast PLL power and ground planes.
Keep switching TTL signals away from differential signals to avoid
possible noise coupling.
Do not route TTL clock signals to areas under or above the
differential signals.
This section provides information on using the Quartus II software to
create Stratix designs with LVDS transmitters or receivers. You can use
the altlvds megafunction in the Quartus II software to implement the
SERDES circuitry. You must bypass the SERDES circuitry in ×1 and ×2
mode designs and use the altddio megafunction to implement the
deserialization instead. You can use either the logic array or the M512
RAM blocks closest to the differential pins for deserialization in SERDES
bypass mode.
Differential Pins in Stratix
Stratix device differential pins are located in I/O banks 1, 2, 5, and 6 (see
Figure 5–1 on page 5–2). Each bank has differential transmitter and
differential receiver pin pairs. You can use each differential transmitter
pin pair as either a differential data pin pair or a differential clock pin pair
because Stratix devices do not have dedicated LVDS tx_outclock pin
pairs. The differential receiver pin pairs can only function as differential
data pin pairs. You can use these differential pins as regular user I/O pins
when not used as differential pins. When using differential signaling in
an I/O bank, you cannot place non-differential output or bidirectional
pads within five I/O pads of either side of the differential pins to avoid a
decrease in performance on the LVDS signals.
You only need to make assignments to the positive pin of the pin-pair.
The Quartus II software automatically reserves and makes the same
assignment to the negative pin. If you do not assign any differential I/O
standard to the differential pins, the Quartus II software sets them as
LVDS differential pins during fitting, if the design uses the SERDES
circuitry. Additionally, if you bypass the SERDES circuitry, you can still
use the differential pins by assigning a differential I/O standard to the
pins in the Quartus II software. However, when you bypass the SERDES
circuitry in the ×1 and ×2 mode, you must assign the correct differential
I/O standard to the associated pins in the Assignment Organizer. For
more information on how to use the Assignment Organizer, see the
Quartus II On-Line Help.
Altera Corporation
July 2005
5–51
Stratix Device Handbook, Volume 2
Software Support
Stratix devices can drive the PLL_LOCK signal to both output pins and
internal logic. As a result, you do not need a dedicated LOCK pin for your
PLLs. In addition, there is only one PLL_ENABLE pin that enables all the
PLLs on the device, including the fast PLLs. You must use either the
LVTTL or LVCMOS I/O standard with this pin.
Table 5–9 displays the LVDS pins in Stratix devices.
Table 5–9. LVDS Pin Names
Pin Names
Functions
DIFFIO_TX#p
Transmitter positive data or output clock pin
DIFFIO_TX#n
Transmitter negative data or output clock pin
DIFFIO_RX#p
Receiver positive data pin
DIFFIO_RX#n
Receiver negative data pin
FPLLCLK#p
Positive input clock pin to the corner fast PLLs (1), (2)
FPLLCLK#n
Negative input clock pin to the corner fast PLLs (1), (2)
CLK#p
Positive input clock pin (2)
CLK#n
Negative input clock pin (2)
Notes to Table 5–9:
(1)
(2)
The FPLLCLK pin-pair is only available in EP1S30, EP1S40, EP1S60, EP1S80
devices.
Either a FPLLCLK pin or a CLK pin can drive the corner fast PLLs (PLL7, PLL8,
PLL9, and PLL10) when used for general purpose. CLK pins cannot drive these
fast PLLs in high-speed differential I/O mode.
Fast PLLs
Each fast PLL features a multiplexed input path from a global or regional
clock net. A clock pin or an output from another PLL in the device can
drive the input path. The input clock for PLLs used to clock receiver the
rx_inclock port on the altlvds_rx megafunction must be driven by
a dedicated clock pin (CLK[3..0,8..11]) or the corner pins that clock the
corner PLLs (FPLL[10..7]CLK). EP1S10, EP1S20, and EP1S25 devices have
a total of four fast PLLs located in the center of both sides of the device
(see Figure 5–16 on page 5–23). EP1S30 and larger devices have two
additional fast PLLs per side at the top and bottom corners of the device.
As shown in Figure 5–17 on page 5–24, the corner fast PLL shares an I/O
bank with the closest center fast PLL (e.g., PLLs 1 and 7 share an I/O
bank). The maximum input clock frequency for enhanced PLLs is 684
MHz and 717 MHz for fast PLLs.
f
For more information on Stratix PLLs, see the General-Purpose PLLs in
Stratix & Stratix GX Devices chapter.
5–52
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
One fast PLL can drive the 20 transmitter channels and 20 receiver
channels closest to it with data rates of up to 840 Mbps. Wire-bond
packages support a data rate of 624 Mbps. The corner fast PLLs in EP1S80
devices support data rates of up to 840 Mbps. See Tables 5–10 through
5–14 for the number of high-speed differential channels in a particular
Stratix device density and package.
Since the fast PLL drives the 20 closest differential channels, there are
coverage overlaps in the EP1S30 and larger devices that have two fast
PLLs per I/O bank. In these devices, either the center fast PLL or the
corner fast PLL can drive the differential channels in the middle of the
I/O bank.
Fast PLLs can drive more than 20 transmitter and 20 receiver channels
(see Tables 5–10 through 5–14 and Figures 5–16, and 5–17 for the number
of channels each PLL can drive). In addition, the center fast PLLs can
drive either one I/O bank or both I/O banks on the same side (left or
right) of the device, while the corner fast PLLs can only drive the
differential channels in its I/O bank. Neither fast PLL can drive the
differential channels in the opposite side of the device.
The center fast PLLs can only drive two I/O at 840 Mbps. For example,
EP1S20 device fast PLL 1 can drive all 33 differential channels on its side
(17 channels from I/O bank 2 and 16 channels from I/O bank 1) running
at 840 Mbps in 4× mode. When a center fast PLL drives the opposite bank
on the same side of the device, the other center fast PLL cannot drive any
differential channels on the device.
See Tables 5–10 through 5–14 for the maximum number of channels that
one fast PLL can drive. The number of channels is also listed in the
Quartus II software. The Quartus II software gives an error message if
you try to compile a design exceeding the maximum number of channels.
f
Altera Corporation
July 2005
Additional high-speed DIFFIO pin information for Stratix devices is
available in Volume 3 of the Stratix Device Handbook.
5–53
Stratix Device Handbook, Volume 2
Software Support
Table 5–10 shows the number of channels and fast PLLs in EP1S10,
EP1S20, and EP1S25 devices. Tables 5–11 through 5–14 show this
information for EP1S30, EP1S40, EP1S60, and EP1S80 devices.
Table 5–10. EP1S10, EP1S20 & EP1S25 Device Differential Channels (Part 1 of 2) Note (1)
Device
EP1S10
Package
Transmitter/
Receiver
484-pin FineLine BGA Transmitter
(2)
Receiver
672-pin FineLine BGA Transmitter
672-pin BGA
(2)
Receiver
780-pin FineLine BGA Transmitter
(2)
Receiver
EP1S20
484-pin FineLine BGA Transmitter
(2)
Receiver
672-pin FineLine BGA Transmitter
672-pin BGA
(2)
Receiver
780-pin FineLine BGA Transmitter
(2)
Receiver
5–54
Stratix Device Handbook, Volume 2
Total
Channels
20
20
36
36
44
44
24
20
48
50
66
66
Maximum
Speed
(Mbps)
Center Fast PLLs
PLL 1
PLL 2
PLL 3
PLL 4
840
5
5
5
5
840 (3)
10
10
10
10
840
5
5
5
5
840 (3)
10
10
10
10
624 (4)
9
9
9
9
624 (3)
18
18
18
18
624 (4)
9
9
9
9
624 (3)
18
18
18
18
840
11
11
11
11
840 (3)
22
22
22
22
840
11
11
11
11
840 (3)
22
22
22
22
840
6
6
6
6
840 (3)
12
12
12
12
840
5
5
5
5
840 (3)
10
10
10
10
624 (4)
12
12
12
12
624 (3)
24
24
24
24
624 (4)
13
12
12
13
624 (3)
25
25
25
25
840
17
16
16
17
840 (3)
33
33
33
33
840
17
16
16
17
840 (3)
33
33
33
33
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Table 5–10. EP1S10, EP1S20 & EP1S25 Device Differential Channels (Part 2 of 2) Note (1)
Device
EP1S25
Package
Transmitter/
Receiver
672-pin FineLine BGA Transmitter
672-pin BGA
(2)
Receiver
780-pin FineLine BGA Transmitter
(2)
Receiver
1,020-pin FineLine
BGA
Total
Channels
Maximum
Speed
(Mbps)
PLL 1
PLL 2
PLL 3
PLL 4
56
624 (4)
14
14
14
14
624 (3)
28
28
28
28
624 (4)
14
15
15
14
624 (3)
29
29
29
29
58
70
66
Transmitter
(2)
78
Receiver
78
Center Fast PLLs
840
18
17
17
18
840 (3)
35
35
35
35
840
17
16
16
17
840 (3)
33
33
33
33
840
19
20
20
19
840 (3)
39
39
39
39
840
19
20
20
19
840 (3)
39
39
39
39
Notes to Table 5–10:
(1)
(2)
(3)
(4)
The first row for each transmitter or receiver reports the number of channels driven directly by the PLL. The second
row below it shows the maximum channels a PLL can drive if cross bank channels are used from the adjacent center
PLL. For example, in the 484-pin FineLine BGA EP1S10 device, PLL 1 can drive a maximum of five channels at
840 Mbps or a maximum of 10 channels at 840 Mbps. The Quartus II software may also merge receiver and
transmitter PLLs when a receiver is driving a transmitter. In this case, one fast PLL can drive both the maximum
numbers of receiver and transmitter channels.
The number of channels listed includes the transmitter clock output (tx_outclock) channel. If the design
requires a DDR clock, it can use an extra data channel.
These channels span across two I/O banks per side of the device. When a center PLL clocks channels in the
opposite bank on the same side of the device it is called cross-bank PLL support. Both center PLLs can clock crossbank channels simultaneously if, for example, PLL_1 is clocking all RX channels and PLL_2 is clocking all TX
channels. You cannot have two adjacent PLLs simultaneously clocking cross-bank RX channels or two adjacent
PLLs simultaneously clocking TX channels. Cross-bank allows for all receiver channels on one side of the device to
be clocked on one clock while all transmitter channels on the device are clocked on the other center PLL. Crossbank
PLLs are supported at full-speed, 840 Mbps. For wire-bond devices, the full-speed is 624 Mbps.
These values show the channels available for each PLL without crossing another bank.
Altera Corporation
July 2005
5–55
Stratix Device Handbook, Volume 2
Software Support
Table 5–11. EP1S30 Differential Channels Note (1)
Package
780-pin
FineLine
BGA
956-pin
FineLine
BGA
1,020-pin
FineLine
BGA
Transmitter
Total
/Receiver Channels
Transmitter
(4)
70
Receiver
66
Transmitter
(4)
80 (7)
Receiver
80 (7)
Transmitter
(4)
80 (2) (7)
Receiver
80 (2) (7)
Maximum
Center Fast PLLs
Corner Fast PLLs (2), (3)
Speed
(Mbps) PLL1 PLL2 PLL3 PLL4 PLL7 PLL8 PLL9 PLL10
840
18
17
17
18
(6)
(6)
(6)
(6)
840 (5)
35
35
35
35
(6)
(6)
(6)
(6)
840
17
16
16
17
(6)
(6)
(6)
(6)
840 (5)
33
33
33
33
(6)
(6)
(6)
(6)
840
19
20
20
19
20
20
20
20
840 (5)
39
39
39
39
20
20
20
20
840
20
20
20
20
19
20
20
19
840 (5)
40
40
40
40
19
20
20
19
840
19
(1)
20
20
19
(1)
20
20
20
20
840 (5),(8)
39
(1)
39
(1)
39
(1)
39
(1)
20
20
20
20
840
20
20
20
20
19 (1)
20
20
19 (1)
840 (5),(8)
40
40
40
40
19 (1)
20
20
19 (1)
Table 5–12. EP1S40 Differential Channels (Part 1 of 2) Note (1)
Package
780-pin
FineLine
BGA
956-pin
FineLine
BGA
Transmitter
Total
/Receiver Channels
Transmitter
(4)
68
Receiver
66
Transmitter
(4)
80
Receiver
80
5–56
Stratix Device Handbook, Volume 2
Maximum
Speed
(Mbps)
Center Fast PLLs
Corner Fast PLLs (2), (3)
PLL1 PLL2 PLL3 PLL4 PLL7 PLL8 PLL9 PLL10
840
18
16
16
18
(6)
(6)
(6)
(6)
840 (5)
34
34
34
34
(6)
(6)
(6)
(6)
840
17
16
16
17
(6)
(6)
(6)
(6)
840 (5)
33
33
33
33
(6)
(6)
(6)
(6)
840
18
17
17
18
20
20
20
20
840 (5)
35
35
35
35
20
20
20
20
840
20
20
20
20
18
17
17
18
840 (5)
40
40
40
40
18
17
17
18
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Table 5–12. EP1S40 Differential Channels (Part 2 of 2) Note (1)
Package
1,020-pin
FineLine
BGA
Transmitter
Total
/Receiver Channels
Transmitter
(4)
Receiver
1,508-pin
FineLine
BGA
Transmitter
(4)
Receiver
80 (10)
(7)
80 (10)
(7)
80 (10)
(7)
80 (10)
(7)
Maximum
Speed
(Mbps)
Center Fast PLLs
Corner Fast PLLs (2), (3)
PLL1 PLL2 PLL3 PLL4 PLL7 PLL8 PLL9 PLL10
840
18
(2)
17
(3)
17
(3)
18
(2)
20
20
20
20
840 (5), (8)
35
(5)
35
(5)
35
(5)
35
(5)
20
20
20
20
840
20
20
20
20
18
(2)
17
(3)
17
(3)
18 (2)
840 (5), (8)
40
40
40
40
18
(2)
17
(3)
17
(3)
18 (2)
840
18
(2)
17
(3)
17
(3)
18
(2)
20
20
20
20
840 (5), (8)
35
(5)
35
(5)
35
(5)
35
(5)
20
20
20
20
840
20
20
20
20
18
(2)
17
(3)
17
(3)
18 (2)
840 (5), (8)
40
40
40
40
18
(2)
17
(3)
17
(3)
18 (2)
Table 5–13. EP1S60 Differential Channels (Part 1 of 2) Note (1)
Package
956-pin
FineLine
BGA
1,020-pin
FineLine
BGA
Transmitter
Total
/Receiver Channels
Transmitter
(4)
80
Receiver
80
Transmitter
(4)
80 (12)
(7)
Receiver
Altera Corporation
July 2005
80 (10)
(7)
Maximum
Center Fast PLLs
Corner Fast PLLs (2), (3)
Speed
PLL1 PLL2 PLL3 PLL4 PLL7 PLL8 PLL9 PLL10
(Mbps)
840
12
10
10
12
20
20
20
20
840 (5), (8)
22
22
22
22
20
20
20
20
840
20
20
20
20
12
10
10
12
840 (5), (8)
40
40
40
40
12
10
10
12
840
12
(2)
10
(4)
10
(4)
12
(2)
20
20
20
20
840 (5), (8)
22
(6)
22
(6)
22
(6)
22
(6)
20
20
20
20
840
20
20
20
20
12
(8)
10
(10)
10
(10)
12 (8)
840 (5), (8)
40
40
40
40
12
(8)
10
(10)
10
(10)
12 (8)
5–57
Stratix Device Handbook, Volume 2
Software Support
Table 5–13. EP1S60 Differential Channels (Part 2 of 2) Note (1)
Package
1,508-pin
FineLine
BGA
Transmitter
Total
/Receiver Channels
Transmitter
(4)
Receiver
80 (36)
(7)
80 (36)
(7)
Maximum
Center Fast PLLs
Corner Fast PLLs (2), (3)
Speed
PLL1 PLL2 PLL3 PLL4 PLL7 PLL8 PLL9 PLL10
(Mbps)
840
12
(8)
10
(10)
10
(10)
12
(8)
20
20
20
20
840 (5),(8)
22
(18)
22
(18)
22
(18)
22
(18)
20
20
20
20
840
20
20
20
20
12
(8)
10
(10)
10
(10)
12 (8)
840 (5),(8)
40
40
40
40
12
(8)
10
(10)
10
(10)
12 (8)
Table 5–14. EP1S80 Differential Channels (Part 1 of 2) Note (1)
Package
956-pin
FineLine
BGA
1,020-pin
FineLine
BGA
Transmitter
Total
/Receiver Channels
Transmitter
(4)
80 (40)
(7)
Receiver
80
Transmitter
(4)
80 (12)
(7)
Receiver
80 (10)
(7)
5–58
Stratix Device Handbook, Volume 2
Maximum
Center Fast PLLs
Corner Fast PLLs (2)
Speed
(Mbps) PLL1 PLL2 PLL3 PLL4 PLL7 PLL8 PLL9 PLL10
840
10
10
10
10
20
20
20
20
840 (5),(8)
20
20
20
20
20
20
20
20
840
20
20
20
20
10
10
10
10
840 (5),(8)
40
40
40
40
10
10
10
10
840
10
(2)
10
(4)
10
(4)
10
(2)
20
20
20
20
840 (5),(8)
20
(6)
20
(6)
20
(6)
20
(6)
20
20
20
20
840
20
20
20
20
10
(2)
10
(3)
10 (3)
10 (2)
840 (5),(8)
40
40
40
40
10
(2)
10
(3)
10 (3)
10 (2)
Altera Corporation
July 2005
High-Speed Differential I/O Interfaces in Stratix Devices
Table 5–14. EP1S80 Differential Channels (Part 2 of 2) Note (1)
Package
1,508-pin
FineLine
BGA
Transmitter
Total
/Receiver Channels
Transmitter
(4)
Receiver
80 (72)
(7)
80 (56)
(7)
Maximum
Center Fast PLLs
Corner Fast PLLs (2)
Speed
(Mbps) PLL1 PLL2 PLL3 PLL4 PLL7 PLL8 PLL9 PLL10
840
10
(10)
10
(10)
10
(10)
10
(10)
20
(8)
20
(8)
20 (8)
20 (8)
840 (5),(8)
20
(20)
20
(20)
20
(20)
20
(20)
20
(8)
20
(8)
20 (8)
20 (8)
840
20
20
20
20
10
(14)
10
(14)
10
(14)
10
(14)
840 (5),(8)
40
40
40
40
10
(14)
10
(14)
10
(14)
10
(14)
Notes to Tables 5–11 through 5–14.
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
The first row for each transmitter or receiver reports the number of channels driven directly by the PLL. The second
row below it shows the maximum channels a PLL can drive if cross bank channels are used from the adjacent center
PLL. For example, in the 780-pin FineLine BGA EP1S30 device, PLL 1 can drive a maximum of 18 transmitter
channels at 840 Mbps or a maximum of 35 transmitter channels at 840 Mbps. The Quartus II software may also
merge transmitter and receiver PLLs when a receiver is driving a transmitter. In this case, one fast PLL can drive
both the maximum numbers of receiver and transmitter channels.
Some of the channels accessible by the center fast PLL and the channels accessible by the corner fast PLL overlap.
Therefore, the total number of channels is not the addition of the number of channels accessible by PLLs 1, 2, 3, and
4 with the number of channels accessible by PLLs 7, 8, 9, and 10. For more information on which channels overlap,
see the Fast PLL to High-Speed I/O Connections section in the relevant device pin table available on the web
(www.altera.com).
The corner fast PLLs in this device support a data rate of 840 Mbps for channels labeled “high” speed in the device
pin tables.
The numbers of channels listed include the transmitter clock output (tx_outclock) channel. You can use an extra
data channel if you need a DDR clock.
These channels span across two I/O banks per side of the device. When a center PLL clocks channels in the opposite
bank on the same side of the device it is called cross-bank PLL support. Both center PLLs can clock cross-bank
channels simultaneously if, for example, PLL_1 is clocking all receiver channels and PLL_2 is clocking all
transmitter channels. You cannot have two adjacent PLLs simultaneously clocking cross-bank receiver channels or
two adjacent PLLs simultaneously clocking transmitter channels. Cross-bank allows for all receiver channels on one
side of the device to be clocked on one clock while all transmitter channels on the device are clocked on the other
center PLL. Crossbank PLLs are supported at full-speed, 840 Mbps. For wire-bond devices, the full-speed is
624 Mbps.
PLLs 7, 8, 9, and 10 are not available in this device.
The number in parentheses is the number of slow-speed channels, guaranteed to operate at up to 462 Mbps. These
channels are independent of the high-speed differential channels. For the location of these channels, see the Fast
PLL to High-Speed I/O Connections section in the relevant device pin table available on the web (www.altera.com).
See device pin-outs channels marked “high” speed are 840 Mbps and “low” speed channels are 462 MBps.
The Quartus II software may also merge transmitter and receiver PLLs
when a receiver block is driving a transmitter block if the Use Common
PLLs for Rx and Tx option is set for both modules. The Quartus II
software does not merge the PLLs in multiple transmitter-only or
multiple receiver-only modules fed by the same clock.
Altera Corporation
July 2005
5–59
Stratix Device Handbook, Volume 2
Software Support
When you span two I/O banks using cross-bank support, you can route
only two load enable signals total between the plls. When you enable
rx_data_align, you use both rxloadena and txloadena of a PLL.
That leaves no loadena for the second PLL.
The only way you can use the rx_data_align is if one of the following
is true:
■
■
The RX PLL is only clocking RX channels (no resources for TX)
If all channels can fit in one I/O bank
LVDS Receiver Block
You only need to enter the input clock frequency, deserialization factor,
and the input data rate to implement an LVDS receiver block. The
Quartus II software then automatically sets the clock boost (W) factor for
the receiver. In addition, you can also indicate the clock and data
alignment for the receiver or add the pll_enable, rx_data_align,
and rx_locked output ports. Table 5–15 explains the function of the
available ports in the LVDS receiver block.
Table 5–15. LVDS Receiver Ports
Port Name
Direction
rx_in[number_of_channels - 1..0] Input
Function
Input Port
Source/Output Port
Destination
Input data channel
Pin
rx_inclock
Input
Reference input clock
Pin or output from a PLL
rx_pll_enable
Input
Enables fast PLL
Pin (1), (2), (3)
rx_data_align
Input
Control for the data
realignment circuitry
Pin or logic array (1),
(3), (4)
rx_locked
Output
Fast PLL locked pin
Pin or logic array (1), (3)
rx_out[Deserialization_factor *
number_of_channels -1..0]
Output
De-serialized data
Logic array
rx_outclock
Output
Internal reference clock
Logic array
Notes to Table 5–15:
(1)
(2)
(3)
(4)
This is an optional port.
Only one rx_pll_enable pin is necessary to enable all the PLLs in the device.
This is a non-differential pin.
See “Realignment Implementation” on page 5–28 for more information. For guaranteed performance and data
alignment, you must synchronize rx_data_align with rx_outclock.
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Use the altlvds MegaWizard Plug-In Manager to create an LVDS
receiver block. The following sections explain the parameters available in
the Plug-In Manager when creating an LVDS receiver block.
Page 3 of the altlvds_rx MegaWizard Plug-In Manager
On page 3 of the altlvds MegaWizard Plug-In Manager, you can
choose to create either an LVDS transmitter or receiver. Depending on
what you select, the MegaWizard Plug-In Manager provides you with
different options. Figure 5–40 shows page 3 of the altlvds MegaWizard
Plug-In Manager with options for creating an LVDS receiver.
Figure 5–40. Page 3 of the altlvds_rx MegaWizard Plug-In Manager
Number of Channels
The What is the number of channels? parameter specifies the number of
receiver channels required and the width of rx_out port. To set a fast
PLL to drive over 20 channels, type the required number in the Quartus II
window instead of choosing a number from the drop-down menu, which
only has selections of up to 20 channels.
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Deserialization Factor
Use the What is the deserialization factor? parameter to specify the
number of bits per channel. The Stratix LVDS receiver supports 4, 7, 8,
and 10 for deserialization factor (J) values. Based on the factor specified,
the Quartus II software determines the multiplication and/or division
factor for the LVDS PLL to deserialize the data.
See Table 5–5 for the differential bit naming convention. The parallel data
for the nth channel spans from the MSB (rx_out bit [(J × n) – 1]) to the
LSB (rx_out bit [J × (n – 1)]), where J is the deserialization factor. The
total width of the receiver rx_out port is equal to the number of channels
multiplied by your deserialization factor.
Input Data Rate
The What is the inclock boost(W)? parameter sets the data rate coming
into the receiver and is usually the deserialization factor (J) multiplied by
the inclock frequency. This parameter’s value must be larger than the
input clock frequency and has a maximum input data rate of 840 Mbps
for Stratix devices. You do not have to provide a value for the inclock
boost (W) when designing with Stratix devices because the Quartus II
software can calculate it automatically from this parameter and the clock
frequency or clock period.
The rx_outclock frequency is (W/J) × input frequency. The parallel
data coming out of the receiver has the same frequency as the
rx_outclock port. The clock-to-data alignment of the parallel data
output from the receiver depends on the What is the alignment of data
with respect to rx_inclock? parameter.
Data Alignment with Clock
The What is the alignment of data with respect to rx_inclock? parameter
adjusts the clock-to-data skew. For most applications, the data is source
synchronous to the clock. However, there are applications where you
must center-align the data with respect to the clock. You can use the What
is the alignment of data with respect to rx_inclock? parameter to align
the input data with respect to the rx_inclock port. The MegaWizard
Plug-In automatically calculates the phase for the fast PLL outputs from
the What is the alignment of data with respect to rx_inclock? parameter.
This parameter’s default value is EDGE_ALIGNED, and other values
available from the pull-down menu are EDGE_ALIGNED,
CENTER_ALIGNED, 45_DEGREES, 135_DEGREES, 180_DEGREES,
225_DEGREES, 270_DEGREES, and 315_DEGREES. CENTER_ALIGNED
is the same as 90 degrees aligned and is useful for applications like
HyperTransport technology.
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Clock Frequency or Clock Period
The fields in the Specify the input clock rate by box specify the input
frequency or the period of the input clock going into the fast PLL. When
using the same input clock to feed a transmitter and receiver
simultaneously, the Quartus II software can use one fast PLL for both the
transmitter and receiver.
Page 4 of the altlvds_rx MegaWizard Plug-In Manager
This section describes the parameters found on page 4 of the
altlvds_rx MegaWizard Plug-In Manager (see Figure 5–41).
Figure 5–41. Page 4 of the altlvds_rx MegaWizard Plug-In Manager
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Data Realignment
Check the Use the “rx_data_align” input port box within the Input Ports
box to add the rx_data_align output port and enable the data
realignment circuitry in Stratix SERDES. See “Receiver Data
Realignment” on page 5–25 for more information. If necessary, you can
create a state machine to send a pulse to the rx_data_align port to
realign the data coming in the LVDS receiver. You need to assert the port
for at least two clock cycles to enable the data realignment circuitry. Go
to the Altera web site at www.altera.com for a sample design written in
Verilog HDL.
For guaranteed performance when using data realignment, check the
Add Extra registers for rx_data_align input box when using the
rx_data_align port. The Quartus II software places one
synchronization register in the LE closest to the rx_data_align port.
Register Outputs
Check the Register outputs box to register the receiver’s output data. The
register acts as the module’s register boundary. If the module fed by the
receiver does not have a register boundary for the data, turn this option
on. The number of registers used is proportional to the deserialization
factor (J). The Quartus II software places the synchronization registers in
the LEs closest to the SERDES circuitry.
Use Common PLL for Both Transmitter & Receiver
Check the Use Common PLLs for Rx and Tx box to place both the LVDS
transmitter and the LVDS receiver in the same Stratix device I/O bank.
The Quartus II software allows the transmitter and receiver to share the
same fast PLL when they use the same input clock. Although you must
separate the transmitter and receiver modules in your design, the
Quartus II software merges the fast PLLs when appropriate and give you
the following message:
Receiver fast PLL <lvds_rx PLL name> and transmitter fast PLL <lvds_tx
PLL name> are merged together
The Quartus II software provides the following message when it cannot
merge the fast PLLs for the LVDS transmitter and receiver pair in the
design:
Can't merge transmitter-only fast PLL <lvds_tx PLL name> and receiveronly fast PLL <lvds_rx PLL name>
rx_outclock Resource
You can use either the global or regional clock for the rx_outclock
signal. If you select Auto in the Quartus II software, the tool uses any
available lines.
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LVDS Transmitter Module
The Quartus II software calculates the inclock boost (W) factor for the
LVDS transmitter based on input data rate, input clock frequency, and
the deserialization factor. In addition to setting the data and clock
alignment, you can also set the outclock divide factor (B) for the
transmitter output clock and add the pll_enable, tx_locked, and
tx_coreclock ports. Table 5–16 explains the function of the available
ports in the LVDS transmitter block.
Table 5–16. LVDS Transmitter Ports
Port Name
Direction
Function
Input port
Source/Output port
Destination
tx_in[Deserialization_factor *
number_of_channels - 1..0]
Input
Input data
Logic array
tx_inclock
Input
Reference input clock
Pin or output clock
from a PLL
tx_pll_enable
Input
tx_out[number_of_channels - 1..0] Output
Fast PLL enable
Pin (1), (2), (3)
Serialized LVDS data
signal
Pin
tx_outclock
Output
External reference clock
Pin
tx_coreclock
Output
Internal reference clock
Pin, logic array, or
input clock to a fast
PLL (1)
tx_locked
Output
Fast PLL locked pin
Pin or logic array (1),
(2), (3)
Notes to Table 5–16:
(1)
(2)
(3)
This is an optional port.
Only one tx_pll_enable pin is necessary to enable all the PLLs in the device.
This is a non-differential pin.
You can also use the altlvds MegaWizard Plug-In Manager to create an
LVDS transmitter block. The following sections explain the parameters
available in the Plug-In Manager when creating an LVDS transmitter
block.
Page 3 of the altlvds_tx MegaWizard Plug-In Manager
This section describes the parameters found on page 3 of the
altlvds_tx MegaWizard Plug-In Manager (see Figure 5–42).
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Figure 5–42. Page 3 of the Transmitter altlvds MegaWizard Plug-In Manager
Number of Channels
The What is the number of channels? parameter specifies the number of
transmitter channels required and the width of the tx_in port. You can
have more than 20 channels in a transmitter or receiver module by typing
in the required number instead of choosing a number from the drop
down menu, which only has selections of up to 20 channels.
Deserialization Factor
The What is the deserialization factor? parameter specifies the number
of bits per channel. The transmitter block supports deserialization factors
of 4, 7, 8, and 10. Based on the factor specified, the Quartus II software
determines the multiplication and/or division factor for the LVDS PLL in
order to serialize the data.
Table 5–5 on page 5–32 lists the differential bit naming convention. The
parallel data for the nth channel spans from the MSB (rx_out bit
[(J × n) – 1]) to the LSB (rx_out bit [J × (n – 1)]), where J is the
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deserialization factor. The total width of the tx_in port of the transmitter
is equal to the number of channels multiplied by the deserialization
factor.
Outclock Divide Factor
The What is the Output data rate? parameter specifies the ratio of the
tx_outclock frequency compared to the data rate. The default value for
this parameter is the value of the deserialization factor parameter. The
tx_outclock frequency is equal to [W/B] x input clock frequency.
There is also an optional tx_coreclock port which has the same
frequency as the [W/J] × input frequency.
The outclock divide factor is useful for applications that do not require
the data rate to be the same as the clock frequency. For example,
HyperTransport technology uses a half-clock data rate scheme where the
clock frequency is half the data rate. Table 5–17 shows the supported
outclock divide factor for a given deserialization factor.
Table 5–17. Deserialization Factor (J) vs. Outclock Divide Factor (B)
Deserialization Factor (J)
Outclock Divide Factor (B)
4
1, 2, 4
7
1, 7(1)
8
1, 2, 4, 8
10
1, 2, 10
Note to Table 5–17:
(1)
The clock does not have a 50% duty cycle when b=7 in x7 mode.
Output Data Rate
The What is the Output data rate parameter specifies the data rate out of
the fast PLL and determines the input clock boost/multiplication factor
needed for the transmitter. This parameter must be larger than the input
clock frequency and has a maximum rate of 840 Mbps for Stratix devices.
The input clock boost factor (W) is the output data rate divided by the
input clock frequency. The Stratix SERDES circuitry supports input clock
boost factors of 4, 7, 8, or 10. The maximum output data rate is 840 Mbps,
while the clock has a maximum output of 500 MHz.
Data Alignment with Clock
Use the What is the alignment of data with respect to tx_inclock?
parameter and the What is the alignment of tx_outclock? to align the
input and output data, respectively, with the clock. For most applications,
the data is edge-aligned with the clock. However, there are applications
where the data must be center-aligned with respect to the clock. With
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Stratix devices, you can align the input data with respect to the
tx_inclock port and align the output data with respect to the
tx_outclock port. The MegaWizard Plug-In Manager uses the
alignment of input and output data to automatically calculate the phase
for the fast PLL outputs. Both of these parameters default to
EDGE_ALIGNED, and other values are CENTER_ALIGNED, 45_DEGREES,
135_DEGREES, 180_DEGREES, 225_DEGREES, 270_DEGREES, and
315_DEGREES. CENTER_ALIGNED is the same as 180 degrees aligned
and is required for the HyperTransport technology I/O standard.
Clock Frequency & Clock Period
The fields in the Specify the input clock rate by box specify either the
frequency or the period of the input clock going into the fast PLL.
However, you cannot specify both. If your design uses the same input
clock to feed a transmitter and a receiver module simultaneously, the
Quartus II software can merge the fast PLLs for both the transmitter and
receiver when the Use common PLLs for Tx & Rx option is turned on.
Page 4 of the altlvds_tx MegaWizard Plug-In Manager
This section describes the parameters found on page 4 of the
altlvds_tx MegaWizard Plug-In Manager (see Figure 5–43).
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High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–43. Page 4 of the Transmitter altlvds MegaWizard Plug-In Manager
Registered Inputs
Check the Register inputs box if the input data to the transmitter is not
registered just before it feeds the transmitter module. You can choose
either tx_clkin or tx_coreclk to clock the transmitter data
(tx_in[]) signal. This serves as the register boundary. The number of
registers used is proportional to the deserialization factor (J). The
Quartus II software places the synchronization registers with the LEs in
the same row and closest to the SERDES circuitry.
Use Common PLL for Transmitter & Receiver
Check the Use Common PLLs for Rx and Tx box to place both the LVDS
transmitter and receiver in the same I/O bank in Stratix devices. The
Quartus II software also allows the transmitter and receiver to share the
PLL when the same input clock is used for both. Although you must
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Software Support
separate the transmitter and receiver in your design, the Quartus II
software merges the fast PLLs when appropriate and gives you the
following message:
Receiver fast PLL <lvds_rx pll name> and transmitter fast PLL
<lvds_tx pll name> are merged together
The Quartus II software gives the following message when it cannot
merge the fast PLLs for the LVDS transmitter and receiver pair in the
design:
Can't merge transmitter-only fast PLL
<lvds_tx pll name> and receiver-only fast PLL
<lvds_rx pll name>
tx_outclock Resource
You can use either the global or regional clock for the tx_outclock
signal. If you select Auto in the Quartus II software, the tool uses any
available lines.
SERDES Bypass Mode
You can bypass the SERDES block if your data rate is less than 624 Mbps,
and you must bypass the SERDES block for the ×1 and ×2 LVDS modules.
Since you cannot route the fast PLL output to an output pin, you must
create additional DDR I/O circuitry for the transmitter clock output. To
create an ×J transmitter output clock, instantiate an alt_ddio
megafunction clocked by the ×J clock with datain_h connected to VCC
and datain_l connected to GND.
×1 Mode
For ×1 mode, you only need to specify the I/O standard of the pins to tell
the Quartus II software that you are using differential signaling.
However, Altera recommends using the DDRIO circuitry when the input
or output data rate is higher than 231 Mbps. The maximum output clock
frequency for ×1 mode is 420 MHz.
×2 Mode
You must use the DDRIO circuitry for ×2 mode. The Quartus II software
provides the altddio_in and altddio_out megafunctions to use for
×2 receiver and ×2 transmitter, respectively. The maximum data rate in
×2 mode is 624 Mbps. Figure 5–44 shows the schematic for using DDR
circuitry in ×2 mode.
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High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–44. LVDS x2 Mode Schematic Using DDR I/O Circuitry
DDIO In
RXp
RXn
datain[0]
inclock
DDIO Out
dataout_h[0]
dataout_l[0]
datain_h[0]
dataout[0]
TXp
TXn
datain_l[0]
Custom Logic
outclock
DDIO Out
RX_PLL
rx_inclk
inclock
/1 clock1
VCC
datain_h[0]
/2 clock0
GND
datain_l[0]
dataout[0]
tx_outclk
outclock
The transmitter output clock requires extra DDR output circuitry that has
the input high and input low connected to VCC and GND respectively. The
output clock frequency is the same as the input frequency of the DDR
output circuitry.
Other Modes
For other modes, you can still to use the DDR circuitry for better
frequency performance. You can use either the LEs or the M512 RAM
block for the deserialization.
M512 RAM Block as Serializer/Deserializer Interface
In addition to using the DDR circuitry and the M512 RAM block, you
need two extra counters per memory block to provide the address for the
memory: a fast counter powering up at 0 and a slow counter powering up
at 2. The M512 RAM block is configured as a simple dual-port memory
block, where the read enable and the write enable signals are always tied
high. Figures 5–45 and 5–46 show the block diagram for the SERDES
bypass receiver and SERDES bypass transmitter, respectively.
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July 2005
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Figure 5–45. SERDES Bypass LVDS Receiver Using M512 RAM Block as the Deserializer
waddr[7..5]
Simple Dual Port
RX_SESB
512 Bits
DDIO In
RXp
datain[0]
RXn
inclock
dataout_h[0]
datain[1..0]
dataout_l[0]
waddr[7..0]
dataout[7..0]
Core data
wclock
clock
q[4..0]
raddr[5..0]
rclock
W-UpCounter
RX_PLL
rx_inclk
inclock
÷1 clock1
÷2 clock0
clock
raddr[5..3]
q[2..0]
R-UpCounter
Core clock
Figure 5–46. SERDES Bypass LVDS Transmitter Using M512 RAM Block as Deserializer
waddr[7..5]
Simple Dual Port ×2×8
TX_SESB
512 Bits
core_data
datain[7..0]
clock
q[2..0]
DDIO Out
dataout[7..0]
datain_h[0]
dataout_h[0]
waddr[5..0]
datain_l[0]
dataout_l[0]
wclock
outclock
TXp
TXn
raddr[7..0]
rclock
W-UpCounter
RX_PLL
core_clk
inclock
÷1 clock1
×2 clock0
clock
q[5..0]
R-UpCounter
raddr[5..3]
RX_PLL
VCC
datain_h[0]
/1 clock1
GND
datain_l[0]
/2 clock0
tx_outclk
outclock
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High-Speed Differential I/O Interfaces in Stratix Devices
For the transmitter, the read counter is the fast counter and the write
counter is the slow counter. For the receiver, the write counter is the fast
counter and the read counter is the slow counter. Tables 5–18 and 5–19
provide the address counter configurations for the transmitter and the
receiver, respectively.
Table 5–18. Address Counters for SERDES Bypass LVDS Receiver
M512 Mode
Deserialization
Factor
Write Up-Counter
(Fast Counter)
Read Up-Counter
(Slow Counter)
Width
Starts at
Width
Starts at
Write
Read
Invalid Initial Cycles
×2×4
4
4
0
3
2
12
6
×2×8
8
5
0
3
2
24
6
×4×16
8
5
0
3
2
24
6
×2×16
16
6
0
3
2
48
6
Table 5–19. Address Counters for SERDES Bypass LVDS Transmitter
M512 Mode
Deserialization
Factor
Write Up-Counter
(Fast Counter)
Read Up-Counter
(Slow Counter)
Width
Starts at
Width
Starts at
Write
Read
Invalid Initial Cycles
×2×4
4
4
0
3
2
2
4
×2×8
8
5
0
3
2
2
8
×4×16
8
5
0
3
2
2
8
×2×16
16
6
0
3
2
2
16
In different M512 memory configurations, the counter width is smaller
than the address width, so you must ground some of the most significant
address bits. Table 5–20 summarizes the address width, the counter
width, and the number of bits to be grounded.
Table 5–20. Address & Counter Width
M512 Mode
Number of Grounded Bits
Write Counter Read Counter Write Address Read Address
Width
Width
Width
Width
Write Address Read Address
×2×4
4
3
8
7
4
4
×2×8
5
3
8
6
3
3
×4×16
6
3
7
5
1
2
×2×16
5
3
8
5
3
2
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Logic Array as Serializer/Deserializer Interface
The design can use the lpm_shift_reg megafunction instead of a
simple dual port memory block to serialize/deserialize data. The receiver
requires an extra flip-flop clocked by the slow clock to latch on to the
deserialized data. The transmitter requires a counter to generate the
enable signal for the shift register to indicate the times to load and
serialize the data. Figures 5–47 and 5–48 show the schematic of the ×8
LVDS receiver and ×8 LVDS transmitter, respectively, with the logic
array performing the deserialization.
This scheme can also be used for APEX II and Mercury device flexible
LVDS solutions.
Figure 5–47. SERDES Bypass LVDS Receiver with Logic Array as Deserializer
clock
Shift
Register
Serial
data in
×4 clock0
Clock
PLL
data_h
data
data[1, 3, 5, 7]
data[7..0]
D
DDR
Input
DFF[7..0]
Q
Data to
logic array
÷2 clock1
data_l
data
data[0, 2, 4, 6]
Shift
Register
CLK
clock
rx_clk
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High-Speed Differential I/O Interfaces in Stratix Devices
Figure 5–48. SERDES Bypass LVDS Transmitter with Logic Array as Deserializer
Counter
Shift
Register
clock
load
data
Data[7..0]
data_l
×4 clock
Clock
PLL
×1 clock
DDR
Output
Shift
Register
data
Serial
data out
data_h
load
clock
tx_clk
Summary
Altera Corporation
July 2005
The Stratix device family of flexible, high-performance, high-density
PLDs delivers the performance and bandwidth necessary for complex
system-on-a-programmable-chip (SOPC) solutions. Stratix devices
support multiple I/O protocols to interface with other devices within the
system. Stratix devices can easily implement processing-intensive datapath functions that are received and transmitted at high speeds. The
Stratix family of devices combines a high-performance enhanced PLD
architecture with dedicated I/O circuitry in order to provide I/O
standard performances of up to 840 Mbps.
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July 2005
Section IV. Digital Signal
Processing (DSP)
This section provides information for design and optimization of digital
signal processing (DSP) functions and arithmetic operations in the onchip DSP blocks.
It contains the following chapters:
Revision History
■
Chapter 6, DSP Blocks in Stratix & Stratix GX Devices
■
Chapter 7, Implementing High Performance DSP Functions
in Stratix & Stratix GX Devices
The table below shows the revision history for Chapters 6 and 7.
Chapter
Date/Version
6
July 2005, v2.2
●
Changed Stratix GX FPGA Family data sheet reference to
Stratix GX Device Handbook, Volume 1.
Changes Made
September 2004, v2.1
●
Updated “Software Support” on page 6–28.
Deleted “Quartus II DSP Megafunctions” section. It was replaced by
the updated “Software Support” on page 6–28
Replaced references to AN 193 and AN 194 with a new reference
on page 6–28.
●
●
7
July 2003, v2.0
●
Minor content change.
April 2003, v1.0
●
No new changes in Stratix Device Handbook v2.0.
September 2004, v1.1
●
Corrected spelling error.
April 2003, v1.0
●
No new changes in Stratix Device Handbook v2.0.
Altera Corporation
Section IV–1
Digital Signal Processing (DSP)
Section IV–2
Stratix Device Handbook, Volume 2
Altera Corporation
6. DSP Blocks in Stratix &
Stratix GX Devices
S52006-2.2
Introduction
Traditionally, designers had to make a trade-off between the flexibility of
off-the-shelf digital signal processors and the performance of custombuilt devices. Altera® Stratix® and Stratix GX devices eliminate the need
for this trade-off by providing exceptional performance combined with
the flexibility of programmable logic devices (PLDs). Stratix and
Stratix GX devices have dedicated digital signal processing (DSP) blocks,
which have high-speed parallel processing capabilities, that are
optimized for DSP applications. DSP blocks are ideal for implementing
DSP applications that need high data throughput.
The most commonly used DSP functions are finite impulse response (FIR)
filters, complex FIR filters, infinite impulse response (IIR) filters, fast
Fourier transform (FFT) functions, discrete cosine transform (DCT)
functions, and correlators. These functions are the building blocks for
more complex systems such as wideband code division multiple access
(W-CDMA) basestations, voice over Internet protocol (VoIP), and highdefinition television (HDTV).
Although these functions are complex, they all use similar building
blocks such as multiply-adders and multiply-accumulators. Stratix and
Stratix GX DSP blocks combine five arithmetic operations—
multiplication, addition, subtraction, accumulation, and summation—to
meet the requirements of complex functions and to provide improved
performance.
This chapter describes the Stratix and Stratix GX DSP blocks, and
explains how you can use them to implement high-performance DSP
functions. It addresses the following topics:
■
■
■
f
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July 2005
Architecture
Operational Modes
Software Support
See the Stratix Device Family Data Sheet section of the Stratix Device
Handbook, Volume 1 and the Stratix GX Device Family Data Sheet section of
the Stratix GX Device Handbook, Volume 1 for more information on Stratix
and Stratix GX devices, respectively.
6–1
DSP Block Overview
DSP Block
Overview
Each Stratix and Stratix GX device has two columns of DSP blocks that
efficiently implement multiplication, multiply accumulate (MAC), and
filtering functions. Figure 6–1 shows one of the columns with
surrounding LAB rows. You can configure each DSP block to support:
■
■
■
Eight 9 × 9 bit multipliers
Four 18 × 18 bit multipliers
One 36 × 36 bit multiplier
Figure 6–1. DSP Blocks Arranged in Columns
DSP Block
Column
8 LAB
Rows
DSP Block
The multipliers can then feed an adder or an accumulator block,
depending on the DSP block operational mode. Additionally, you can use
the DSP block input registers as shift registers to implement applications
such as FIR filters efficiently. The number of DSP blocks per column
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DSP Blocks in Stratix & Stratix GX Devices
increases with device density. Tables 6–1 and 6–2 describe the number of
DSP blocks in each Stratix and Stratix GX device, respectively, and the
multipliers that you can implement.
Table 6–1. Number of DSP Blocks in Stratix Devices Note (1)
Device
DSP Blocks
9 × 9 Multipliers
18 × 18 Multipliers 36 × 36 Multipliers
EP1S10
6
48
24
6
EP1S20
10
80
40
10
EP1S25
10
80
40
10
EP1S30
12
96
48
12
EP1S40
14
112
56
14
EP1S60
18
144
72
18
EP1S80
22
176
88
22
Table 6–2. Number of DSP Blocks in Stratix GX Devices Note (1)
Device
DSP Blocks
9 × 9 Multipliers
EP1SGX10C
6
48
18 × 18 Multipliers 36 × 36 Multipliers
24
6
EP1SGX10D
6
48
24
6
EP1SGX25C
10
80
40
10
EP1SGX25D
10
80
40
10
EP1SGX25F
10
80
40
10
EP1SGX40D
14
112
56
14
EP1SGX40G
14
112
56
14
Note to Tables 6–1 and 6–2:
(1)
Each device has either the number of 9 × 9-, 18 × 18-, or 36 × 36-bit multipliers shown.The total number of
multipliers for each device is not the sum of all the multipliers.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
DSP Block Overview
Figure 6–2 shows the DSP block operating as an 18 × 18 multiplier.
Figure 6–2. DSP Block in 18 × 18 Mode
Optional Serial Shift Register
Inputs from Previous
DSP Block
From the Row
Interface Block
D
PRN
Q
ENA
CLRN
D
PRN
Q
Multiplier Block
D
Adder Output Block
Output
Register
PRN
Q
ENA
CLRN
ENA
CLRN
Adder/
Subtractor/
Accumulator
D
PRN
Q
ENA
CLRN
D
PRN
Q
D
PRN
Q
ENA
CLRN
Summation
Block
ENA
CLRN
Adder
D
PRN
Q
ENA
CLRN
D
PRN
Q
D
PRN
Q
ENA
CLRN
ENA
CLRN
Adder/
Subtractor/
Accumulator
D
PRN
Q
ENA
CLRN
D
PRN
Q
Pipeline
Register
D
PRN
Q
ENA
CLRN
ENA
CLRN
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DSP Blocks in Stratix & Stratix GX Devices
Architecture
The DSP block consists of the following elements:
■
■
■
■
■
■
A multiplier block
An adder/subtractor/accumulator block
A summation block
An output interface
Output registers
Routing and control signals
Multiplier Block
Each multiplier block has input registers, a multiplier stage, and a
pipeline register. See Figure 6–3.
Figure 6–3. Multiplier Block Architecture
signa
signb
aclr[3..0]
clock[3..0]
ena[3..0]
shiftinb
shiftina
D
Data A
Q
ENA
CLRN
D
Q
ENA
Data Out
to Adder
Blocks
CLRN
D
Data B
Q
ENA
CLRN
shiftoutb
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July 2005
shiftouta
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Architecture
Input Registers
Each operand feeds an input register or the multiplier directly. The DSP
block has the following signals (one of each controls every input and
output register):
■
■
■
clock[3..0]
ena[3..0]
aclr[3..0]
The input registers feed the multiplier and drive two dedicated shift
output lines, shiftouta and shiftoutb. The shift outputs from one
multiplier block directly feed the adjacent multiplier block in the same
DSP block (or the next DSP block), as shown in Figure 6–4 on page 6–7, to
form a shift register chain. This chain can terminate in any block, i.e., you
can create any length of shift register chain up to 224 registers. A shift
register is useful in DSP applications such as FIR filters. When
implementing 9 × 9 and 18 × 18 multipliers, you do not need external
logic to create the shift register chain because the input shift registers are
internal to the DSP block. This implementation greatly reduces the
required LE count and routing resources, and produces repeatable
timing.
6–6
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DSP Blocks in Stratix & Stratix GX Devices
Figure 6–4. Shift Register Chain
DSP Block 0
Data A
D
Q
ENA
A[n] × B[n]
CLRN
Data B
D
Q
Q
D
ENA
CLRN
ENA
CLRN
shiftoutb
shiftouta
D
Q
ENA
A[n - 1] × B[n - 1]
CLRN
D
Q
D
Q
ENA
CLRN
ENA
CLRN
shiftoutb
shiftouta
DSP Block 1
D
Q
ENA
A[n - 2] × B[n - 2]
CLRN
D
Q
D
Q
ENA
CLRN
ENA
CLRN
shiftoutb
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July 2005
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Architecture
Multiplier Stage
The multiplier stage supports 9 × 9, 18 × 18, or 36 × 36 multiplication.
(The multiplier stage also support smaller multipliers. See “Operational
Modes” on page 6–18 for details.) Based on the data width, a single DSP
block can perform many multiplications in parallel.
The multiplier operands can be signed or unsigned numbers. Two
signals, signa and signb, indicate the representation of the two
operands. For example, a logic 1 on the signa signal indicates that data
A is a signed number; a logic 0 indicates an unsigned number. The result
of the multiplication is signed if any one of the operands is a signed
number, as shown in Table 6–3.
Table 6–3. Multiplier Signed Representation
Data A
Data B
Result
Unsigned
Unsigned
Unsigned
Unsigned
Signed
Signed
Signed
Unsigned
Signed
Signed
Signed
Signed
The signa and signb signals affect the entire DSP block. Therefore, all
of the data A inputs feeding the same DSP block must have the same sign
representation. Similarly, all of the data B inputs feeding the same DSP
block must have the same sign representation. The multiplier offers full
precision regardless of the sign representation.
1
By default, the Altera Quartus® II software sets the multiplier to
perform unsigned multiplication when the signa and signb
signals are not used.
Pipeline Registers
The output from the multiplier can feed a pipeline register or be
bypassed. You can use pipeline registers for any multiplier size;
pipelining is useful for increasing the DSP block performance,
particularly when using subsequent adder stages.
1
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In the DSP block, pipelining improves the performance of
36 × 36 multipliers. For 18 × 18 multipliers and smaller,
pipelining adds latency but does not improve performance.
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July 2005
DSP Blocks in Stratix & Stratix GX Devices
Adder/Output Block
The adder/output block has the following elements (See Figure 6–5 on
page 6–10):
■
■
■
■
An adder/subtractor/accumulator block
A summation block
An output select multiplexer
Output registers
You can configure the adder/output block as:
■
■
■
■
■
A pure output interface
An accumulator
A simple one-level adder
A two-level adder with dynamic addition/subtraction control on the
first-level adder
The final stage of a 36-bit multiplier
The output select multiplexer sets the output of the DSP block. You can
register the adder/output block’s output using the output registers.
1
Altera Corporation
July 2005
You cannot use the adder/output block independently of the
multiplier.
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Stratix Device Handbook, Volume 2
Architecture
Figure 6–5. Adder/Output Block
Accumulator Feedback
Output Select
Multiplexer
accum_sload0
Result A
Output
Registers
overflow0
Adder/
Subtractor/
Accumulator 0
addnsub1
Result B
signa
Adder
signb
Result C
Adder/
Subtractor/
Accumulator 1
addnsub3
overflow1
Result D
Accumulator Feedback
accum_sload1
Adder/Subtractor/Accumulator Block
The adder/subtractor/accumulator is the first level of the adder/output
block. You can configure the block as an accumulator or as an
adder/subtractor.
Accumulator
When the adder/subtractor/accumulator is configured as an
accumulator, the output of the adder/output block feeds back to the
accumulator as shown in Figure 6–5. You can use the
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DSP Blocks in Stratix & Stratix GX Devices
accum_sload[1..0] signals to clear the accumulator asynchronously.
This action is not the same as resetting the output registers. You can clear
the accumulation and begin a new one without losing any clock cycles.
The overflow signal goes high on the positive edge of the clock when
the accumulator overflows or underflows. In the next clock cycle,
however, the overflow signal resets to zero even though an overflow (or
underflow) occurred in the previous clock cycle. Use a latch to preserve
the overflow condition indefinitely (until the latch is cleared).
Adder/Subtractor
The addnsub[1..0] signals select addition or subtraction: high for
addition and low for subtraction. You can control the addnsub[1..0]
signals using external logic; therefore, the first-level block can switch
from an adder to a subtractor dynamically, simply by changing the
addnsub[1..0] signals. If the first stage is configured as a subtractor,
the output is A - B and C - D.
The adder/subtractor also uses two signals, signa and signb, like the
multiplier block. These signals indicate the sign representation of both
operands together. You can register the signals with a latency of 1 or 2
clock cycles.
Summation Block
The output from the adder/subtractor feeds to an optional summation
block, which is an adder block that sums the outputs of the
adder/subtractor. The summation block is important in applications
such as FIR filters.
Output Select Multiplexer
The outputs from the various elements of the adder/output block are
routed through an output select multiplexer. Based on the DSP block
operational mode, the outputs of the multiplier block,
adder/subtractor/accumulator, or summation block feed straight to the
output, bypassing the remaining blocks in the DSP block.
1
The output select multiplier configuration is configured
automatically by software.
Output Registers
You can use the output registers to register the DSP block output. Like the
input registers, the output registers are controlled by the four
clock[3..0], aclr[3..0], and ena[3..0] signals. You can use the
output registers in any DSP block operational mode.
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Stratix Device Handbook, Volume 2
Architecture
1
The output registers form part of the accumulator in the
multiply-accumulate mode.
Routing Structure & Control Signals
This section describes the interface between the DSP blocks and the row
interface blocks. It also describes how the DSP block generates control
signals and how the signals route from the row interface to the DSP block.
DSP Block Interface
The DSP blocks are organized in columns, which provides efficient
horizontal communication between the blocks and the column-based
memory blocks. The DSP block communicates with other parts of the
device through an input and output interface. Each DSP block, including
the input and output interface, is 8 logic array blocks (LABs) long.
The DSP block and row interface blocks consist of eight blocks that
connect to eight adjacent LAB rows on the left and right. Each of the eight
blocks has two regions: right and left, one per row. The DSP block
receives 144 data input signals and 18 control signals for a total of
162 input signals. This block drives out 144 data output signals; 2 of the
data signals can be used as overflow signals (overflow). Figure 6–6
provides an overview of the DSP block and its interface to adjacent LABs.
Figure 6–6. DSP Block Interface to Adjacent LABs
DSP Block & Row Interface
144
8 LAB 162
Rows
Row
Interfaces
0 through 7
Data
DSP
Block
144
8 LAB
Rows
18
Control
DSP Block
Input Interface
DSP Block
Output Interface
Input Interface
The DSP block input interface has 162 input signals from adjacent LABs;
18 data signals per row and 18 control signals per block.
Output Interface
The DSP block output interface drives 144 outputs to adjacent LABs, 18
signals per row from 8 rows.
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DSP Blocks in Stratix & Stratix GX Devices
Because the DSP block outputs communicate horizontally, and because
each DSP block row has more outputs than an LAB (18 from the DSP
block compared to 10 from an LAB), the DSP block has double the
number of row channel drivers compared to an LAB. The DSP block has
the same number of row channels, but the row channels are staggered as
if there were two LABs within each block. The DSP blocks have the same
number of column channels as LABs because DSP blocks communicate
primarily through row channels.
Row Interface Block
Each row interface block connects to the DSP block row structure with
21 signals. Because each DSP block has eight row interface blocks, this
block receives 162 signals from the eight row interfaces. Of the
162 signals, 144 are data inputs and 18 are control signals. Figure 6–7 on
page 6–14 shows one row block within the DSP block.
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July 2005
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Architecture
Figure 6–7. DSP Row Interface Block
C4 and C8
Interconnects
DirectLink Interconnect
from Adjacent LAB
R4 and R8 Interconnects
Nine DirectLink Outputs
to Adjacent LABs
DirectLink Interconnect
from Adjacent LAB
18
DSP Block
Row Structure
LAB
10
LAB
9
9
10
3
Control
18
18
[17..0]
[17..0]
Row Interface
Block
DSP Block to
LAB Row Interface
Block Interconnect Region
18 Inputs per Row
18 Outputs per Row
Control Signals in the Row Interface Block
The DSP block has a set of input registers, a pipeline register, and an
output register. Each register is grouped in banks that share the same
clock and clear resources:
■
■
■
1- to 9-bit banks for the input register
1- to 18-bit banks for the pipeline register
18 bits for the output register
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July 2005
DSP Blocks in Stratix & Stratix GX Devices
The row interface block generates the control signals and routes them to
the DSP block. Each DSP block has 18 control signals:
■
■
■
■
■
■
Four clock signals (clock[3..0]), which are available to each bank
of DSP blocks
Four clear signals (aclr[3..0]), which are available to each bank
of DSP blocks
Four clock enable signals (ena[3..0]), which the whole DSP block
can use
signa and signb, which are specific to each DSP block
addnsub[1..0] signals
accum_sload[1..0] signals
The signa, signb, and addnsub[1..0], accum_sload[1..0]
signals have independent clocks and clears and can be registered
individually. When each 18 × 18 multiplier in the DSP block splits in half
to two 9 × 9 multipliers, each 9 × 9 multiplier has independent control
signals. Figure 6–8 shows the DSP block row interface and shows how it
generates the data and control signals.
Figure 6–8. DSP Block Row Interface
30 Local
Interconnect
Signals
21 Signals for
Data to Input
Register
DSP Row
LAB
Row
Clocks
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
DSP Block
Row Interface
Bit 8
DSP Row 2
DSP Row 1
DSP Row 3
DSP Row
Unit Control
Block
DSP Row
Bit 9
Bit 10
3
Detail of
1 DSP Row
DSP Row 4
DSP Row 5
Input
Registers
DSP
Block
DSP Row 6
DSP Row 7
DSP Row 8
Bit 11
Bit 12
Bit 13
Bit 14
Bit 15
Bit 16
Bit 17
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July 2005
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Architecture
The DSP block interface generates the clock signals from LAB row clocks
or the local interconnect. The clear signals are generated from the local
interconnects within each DSP block row interface or from LAB row
clocks. The four clock enable signals are generated from the 30 local
interconnects from the same LAB rows that generate the clock signals.
The clock enable is paired with the clock because the enable logic is
implemented at the interface. Figure 6–9 shows the signal distribution
within the row interface block.
Figure 6–9. DSP Block Row Interface Signal Distribution
aclr[3..0]
ena[3..0]
data[17..0]
18
4
4
clock[3..0]
4
Input
18 Registers
18-Bit Data Routed
from 30 Local
Interconnects
18
A1
Four Clock Enable
Signals Routed from
30 Local Interconnects
18 × 18
Multiplier
Row 1
B1
18
Four Clear Signals
Routed from 30 Local
Interconnects or LAB
Row Clock
Four Clock Signals
Routed from LAB
Row Clock or Local
Interconnect
18
Row 2
18
18
A4
18 × 18
Multiplier
Row 7
B4
18
18
Row 8
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July 2005
DSP Blocks in Stratix & Stratix GX Devices
Each row block provides 18 bits of data to the multiplier (i.e., one of the
operands to the multiplier), which are routed through the 30 local
interconnects within each DSP row interface block. Any signal in the
device can be the source of the 18-bit multiplier data, by connecting to the
local row interconnect through any row or column.
Each control signal routes through one of the eight rows of the DSP block.
Table 6–4 shows the 18 control signals and the row to which each one
routes.
Table 6–4. Control Signals in DSP Block
Signal Name
Row
signa
1
signb
6
addnsub1
3
addnsub3
7
accum_sload0 2
accum_sload1 7
Description
DSP block-wide signed and unsigned control signals for all multipliers.
The multiplier outputs are unsigned only if both signa and signb are
low.
Controls addition or subtraction of the two one-level adders. The
addnsub0 signal controls the top two one-level adders; the addnsub1
signal controls the bottom two one-level adders. A high indicates
addition; a low indicates subtraction.
Resets the feedback input to the accumulator. The signal
asynchronously clears the accumulator and allows new accumulation to
begin without losing any clock cycles. The accum_sload0 controls the
top two one-level adders, and the accum_sload1 controls the bottom
two one-level adders. A low is for normal accumulation operations and
a high is for zeroing the accumulator.
clock0
3
clock1
4
DSP block-wide clock signals.
clock2
5
clock3
6
aclr0
1
aclr1
4
aclr2
5
aclr3
7
ena[3..0]
Same rows as the DSP block-wide clock enable signals.
Clock Signals
DSP block-wide clear signals.
Input/Output Data Interface Routing
The 30 local interconnects generate the 18 inputs to the row interface
blocks. The 21 outputs of the row interface block are the inputs to the DSP
row block (see Figure 6–7 on page 6–14).
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July 2005
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Operational Modes
The row interface block has DirectLink™ connections that connect the
DSP block input or output signals to the left and right adjacent LABs at
each row. (The DirectLink connections provide interconnects between
LABs and adjacent blocks.) The DirectLink connection reduces the use of
row and column interconnects, providing higher performance and
flexibility.
Each row interface block receives 10 DirectLink connections from the
right adjacent LABs and 10 from the left adjacent LABs. Additionally, the
row interface block receives signals from the DSP block, making a total of
30 local interconnects for each row interface block. All of the row and
column resources within the DSP block can access this interconnect
region (see Figure 6–7 on page 6–14).
A DSP block has nine outputs that drive the right adjacent LAB and nine
that drive the left adjacent LAB through DirectLink interconnects. All
18 outputs drive any row or column.
Operational
Modes
You can use the DSP block in one of four operational modes, depending
on your application needs (see Table 6–4). The Quartus II software has
built-in megafunctions that you can use to control the mode. After you
have made your parameter settings using the megafunction’s
MegaWizard® Plug-In, the Quartus II software automatically configures
the DSP block.
Table 6–5. DSP Block Operational Modes
9× 9
Mode
18 × 18
36 × 36
Simple multiplier
Eight multipliers with eight Four multipliers with four
product outputs
product outputs
One multiplier
Multiply accumulator
Two 34-bit multiplyaccumulate blocks
–
Two-multiplier adder
Four two-multiplier adders Two two-multiplier adders
–
Four-multiplier adder
Two four-multiplier adders One four-multiplier adder
–
Two 52-bit multiplyaccumulate blocks
Simple Multiplier Mode
In simple multiplier mode, the DSP block performs individual
multiplication operations for general-purpose multipliers and for
applications such as equalizer coefficient updates that require many
individual multiplication operations.
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DSP Blocks in Stratix & Stratix GX Devices
9- & 18-Bit Multipliers
You can configure each DSP block multiplier for 9 or 18 bits. A single DSP
block can support up to 8 individual 9-bit or smaller multipliers, or up to
4 individual multipliers with operand widths between 10- and 18-bits.
Figure 6–10 shows the simple multiplier mode.
Figure 6–10. Simple Multiplier Mode
signa
Adder Output Block
A
Q
D
A
ENA
CLRN
B
Q
D
ENA
CLRN
Q
D
ENA
CLRN
shiftoutb
shiftouta
signb
The multiplier operands can accept signed integers, unsigned integers, or
a combination. The signa and signb signals are dynamic and can be
registered in the DSP block. Additionally, you can register the multiplier
inputs and results independently. Pipelining the result, using the
pipeline registers in the block, increases the performance of the DSP
block.
36-Bit Multiplier
The 36-bit multiplier is a subset of the simple multiplier mode. It uses the
entire DSP block to implement one 36 × 36-bit multiplier. The four 18-bit
multipliers are fed part of each input, as shown in Figure 6–11 on
page 6–21. The adder/output block adds the partial products using the
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Operational Modes
summation block. You can use pipeline registers between the multiplier
stage and the summation block. The 36 × 36-bit multiplier supports
signed and unsigned operation.
The 36-bit multiplier is useful when your application needs more than
18-bit precision, for example, for mantissa multiplication of precision
floating-point arithmetic applications.
6–20
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DSP Blocks in Stratix & Stratix GX Devices
Figure 6–11. 36-Bit Multiplier
signa
signb
A[17..0]
D
Q
ENA
CLRN
Q
D
ENA
CLRN
B[17..0]
D
Q
ENA
A
CLRN
A[35..18]
D
Q
B
ENA
CLRN
D
Q
ENA
Partial
Product
Summation
Block
CLRN
B[35..18]
D
D
Q
ENA
Q
Data Out
CLRN
ENA
CLRN
A[35..18]
D
Q
C
ENA
CLRN
D
Q
ENA
CLRN
B[17..0]
D
D
Q
ENA
CLRN
A[17..0]
D
Q
ENA
CLRN
D
Q
ENA
CLRN
B[35..18]
D
Q
ENA
CLRN
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July 2005
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Operational Modes
Multiply Accumulator Mode
In multiply accumulator mode, the output of the multiplier stage feeds
the adder/output block, which is configured as an accumulator or
subtractor (see Figure 6–12). You can implement up to two independent
18-bit multiply accumulators in one DSP block. The Quartus II software
implements smaller multiplier-accumulators by tying the unused loworder bits of an 18-bit multiplier to ground.
Figure 6–12. Multiply Accumulator Mode
signa (1)
signb (1)
aclr
clock
ena
shiftina
shiftinb
D
Data A
Q
D
ENA
D
Q
Q
Data Out
ENA
ENA
CLRN
Accumulator
CLRN
CLRN
D
Data B
Q
D
ENA
Q
overflow
ENA
CLRN
CLRN
shiftoutb
addnsub1
signa
shiftouta
signb
accum_sload1
Note to Figure 6–12:
(1)
The signa and signb signals are the same in the multiplier stage and the adder/output block.
The multiply accumulator output can be up to 52 bits wide for a
maximum 36-bit result with 16-bits of accumulation. In this mode, the
DSP block uses output registers and the accum_sload and overflow
signals. The accum_sload[1..0] signal synchronously loads the
multiplier result to the accumulator output. This signal can be
unregistered or registered once or twice. The DSP block can then begin a
new accumulation without losing any clock cycles. The overflow signal
indicates an overflow or underflow in the accumulator. This signal is
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July 2005
DSP Blocks in Stratix & Stratix GX Devices
cleared for the next accumulation cycle, and you can use an external latch
to preserve the signal. You can use the addnsub[1..0] signals to
perform accumulation or subtraction dynamically.
1
If you want to use DSP blocks and your design only has an
accumulator, you can use a multiply by one followed by an
accumulator to force the software to implement the logic in the
DSP block.
Two-Multiplier Adder Mode
The two-multiplier adder mode uses the adder/output block to add or
subtract the outputs of the multiplier block, which is useful for
applications such as FFT functions and complex FIR filters. Additionally,
in this mode, the DSP block outputs two sums or differences for
multipliers up to 18 bits, or 4 sums or differences for 9-bit or smaller
multipliers. A single DSP block can implement one 18 × 18-bit complex
multiplier or two 9 × 9-bit complex multipliers.
A complex multiplication can be written as:
(a + jb) × (c + jd) = (a × c – b × d) + j × (a × d + b × c)
In this mode, a single DSP block calculates the real part (a × c – b × d) using
one adder/subtractor/accumulator and the imaginary part (a × d + b × c)
using another adder/subtractor/accumulator for data up to 18 bits.
Figure 6–13 shows an 18-bit complex multiplication. For data widths up
to 9 bits, the DSP block can perform two complex multiplications using
four one-level adders. Resources outside of the DSP block route each
input to the two multiplier inputs.
1
Altera Corporation
July 2005
You can only use the adder block if it follows multiplication
operations.
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Operational Modes
Figure 6–13. Complex Multiplier Implemented Using Two-Multiplier Adder
Mode
18
DSP Block
18
A
36
18
C
37
A×C-B×D
(Real Part)
Subtractor
18
B
36
18
D
18
A
36
18
D
37
Adder
18
B
A×D+B×C
(Imaginary Part)
36
18
C
Four-Multiplier Adder Mode
In the four-multiplier adder mode, which you can use for 1-dimensional
and 2-dimensional filtering applications, the DSP block adds the results
of two adder/subtractor/accumulators in a final stage (the summation
block).
1
You can only use the adder block if it follows multiplication
operations.
9- & 18-Bit Summation Blocks
A single DSP block can implement one 18 × 18 or two 9 × 9 summation
blocks (see Figure 6–14 on page 6–25). The multiplier product widths
must be the same size.
6–24
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
DSP Blocks in Stratix & Stratix GX Devices
Figure 6–14. Four-Multiplier Adder Mode
signa
signb
aclr
clock
ena
shiftina
shiftinb
D
Data A
Q
ENA
CLRN
D
Q
ENA
Adder/
Subtractor
CLRN
D
Data B
Q
ENA
CLRN
D
Data A
Q
Q
D
ENA
ENA
CLRN
D
Q
ENA
CLRN
D
Data B
Q
addnsub0
signa
signb
addnsub1
Data Out
Adder
CLRN
ENA
CLRN
D
Data A
Q
ENA
CLRN
D
Q
ENA
Adder/
Subtractor
CLRN
D
Data B
Q
ENA
CLRN
D
Data A
Q
ENA
CLRN
Q
D
ENA
CLRN
D
Data B
Q
ENA
CLRN
shiftoutb
Altera Corporation
July 2005
shiftouta
6–25
Stratix Device Handbook, Volume 2
Operational Modes
FIR Filters
The four-multiplier adder mode can be used for FIR filter and complex
FIR filter applications. The DSP block combines a four-multiplier adder
with the input registers configured as shift registers. One set of shift
inputs contains the filter data, while the other holds the coefficients,
which can be loaded serially or in parallel (see Figure 6–15).
The input shift register eliminates the need for shift registers external to
the DSP block (e.g., implemented in device logic elements). This
architecture simplifies filter design and improves performance because
the DSP block implements all of the filter circuitry.
1
Serial shift inputs in 36-bit simple multiplier mode require
external registers.
One DSP block can implement an entire 18-bit FIR filter with up to four
taps. For FIR filters larger than four taps, you can cascade DSP blocks
with additional adder stages implemented in logic elements.
6–26
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
DSP Blocks in Stratix & Stratix GX Devices
Figure 6–15. Input Shift Registers Configured for a FIR Filter
Data A
D
Q
ENA
A[n] × B[n] (to adder)
CLRN
Data B
D
Q
Q
D
ENA
CLRN
ENA
CLRN
Data B
Data A
D
Q
ENA
A[n - 1] × B[n - 1] (to adder)
CLRN
D
Q
D
Q
ENA
CLRN
ENA
CLRN
Data B
Data A
D
Q
ENA
A[n - 2] × B[n - 2] (to adder)
CLRN
D
Q
Q
D
ENA
CLRN
ENA
CLRN
Altera Corporation
July 2005
6–27
Stratix Device Handbook, Volume 2
Software Support
Software
Support
Altera provides two distinct methods for implementing various modes of
the DSP block in your design: instantiation and inference. Both methods
use the following three Quartus II megafunctions:
■
■
■
lpm_mult
altmult_add
altmult_accum
You can instantiate the megafunctions in the Quartus II software to use
the DSP block. Alternatively, with inference, you can create a HDL design
an synthesize it using a third-party synthesis tool like LeonardoSpectrum
or Synplify or Quartus II Native Synthesis that infers the appropriate
megafunction by recognizing multipliers, multiplier adders, and
multiplier accumulators. Using either method, the Quartus II software
maps the functionality to the DSP blocks during compilation.
Conclusion
f
See the Implementing High-Performance DSP Functions in Stratix & Stratix
GX Devices chapter in the Stratix Device Handbook, Volume 2 or the
Stratix GX Device Handbook, Volume 2 for more information on using DSP
blocks to implement high-performance DSP functions such as FIR filters,
IIR filters, and discreet cosine transforms (DCTs).
f
See Quartus II On-Line Help for instructions on using the megafunctions
and the MegaWizard Plug-In Manager.
f
For more information on DSP block inference support, see the
Recommended HDL Coding Styles chapter of the Quartus II Development
Software Handbook v4.1, Volume 1.
The Stratix and Stratix GX device DSP blocks are optimized to support
DSP applications that need high data throughput, such as FIR filters, FFT
functions, and encoders. These DSP blocks are flexible and can be
configured in one of four operational modes to suit any application need.
The DSP block’s adder/subtractor/accumulator and the summation
blocks minimize the amount of logic resources used and provide efficient
routing. This efficiency results in improved performance and data
throughput for DSP applications. The Quartus II software, together with
the LeonardoSpectrum and Synplify software, provides a complete and
easy-to-use flow for implementing functionality in the DSP block.
6–28
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
7. Implementing High
Performance DSP Functions
in Stratix & Stratix GX Devices
S52007-1.1
Introduction
Digital signal processing (DSP) is a rapidly advancing field. With
products increasing in complexity, designers face the challenge of
selecting a solution with both flexibility and high performance that can
meet fast time-to-market requirements. DSP processors offer flexibility,
but they lack real-time performance, while application-specific standard
products (ASSPs) and application-specific integrated circuits (ASICs)
offer performance, but they are inflexible. Only programmable logic
devices (PLDs) offer both flexibility and high performance to meet
advanced design challenges.
The mathematical theory underlying basic DSP building blocks—such as
the finite impulse response (FIR) filter, infinite impulse response (IIR)
filter, fast fourier transform (FFT), and direct cosine transform (DCT)—is
computationally intensive. Altera® Stratix® and Stratix GX devices
feature dedicated DSP blocks optimized for implementing arithmetic
operations, such as multiply, multiply-add, and multiply-accumulate.
In addition to DSP blocks, Stratix and Stratix GX devices have
TriMatrix™ embedded memory blocks that feature various sizes that can
be used for data buffering, which is important for most DSP applications.
These dedicated hardware features make Stratix and Stratix GX devices
an ideal DSP solution.
This chapter describes the implementation of high performance DSP
functions, including filters, transforms, and arithmetic functions, using
Stratix and Stratix GX DSP blocks. The following topics are discussed:
■
■
■
■
■
Stratix &
Stratix GX DSP
Block Overview
Altera Corporation
September 2004
FIR filters
IIR filters
Matrix manipulation
Discrete Cosine Transform
Arithmetic functions
Stratix and Stratix GX devices feature DSP blocks that can efficiently
implement DSP functions, including multiply, multiply-add, and
multiply-accumulate. The DSP blocks also have three built-in registers
sets: the input registers, the pipeline registers at the multiplier output,
and the output registers. Figure 7–1 shows the DSP block operating in the
18 × 18-bit mode.
7–1
Stratix & Stratix GX DSP Block Overview
Figure 7–1. DSP Block Diagram for 18 x 18-bit Mode
Optional Serial Shift Register
Inputs from Previous
DSP Block
Multiplier Stage
D
Optional Stage Configurable
as Accumulator or Dynamic
Adder/Subtractor
Q
ENA
CLRN
D
D
ENA
CLRN
Q
Output Selection
Multiplexer
Q
ENA
CLRN
Adder/
Subtractor/
Accumulator
1
D
Q
ENA
CLRN
D
D
ENA
CLRN
Q
Q
ENA
CLRN
Summation
D
Q
ENA
CLRN
D
D
ENA
CLRN
Q
Q
Summation Stage
for Adding Four
Multipliers Together
Optional Output
Register Stage
ENA
CLRN
Adder/
Subtractor/
Accumulator
2
D
Optional Serial
Shift Register
Outputs to
Next DSP Block
in the Column
Q
ENA
CLRN
D
D
ENA
CLRN
Q
ENA
CLRN
7–2
Stratix Device Handbook, Volume 2
Q
Optional Pipeline
Register Stage
Optional Input Register
Stage with Parallel Input or
Shift Register Configuration
to MultiTrack
Interconnect
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
The DSP blocks are organized into columns enabling efficient horizontal
communication with adjacent TriMatrix memory blocks. Tables 7–1 and
7–2 show the DSP block resources in Stratix and Stratix GX devices,
respectively.
Table 7–1. DSP Block Resources in Stratix Devices
DSP Blocks
Maximum 9 × 9
Multipliers
Maximum 18 × 18
Multipliers
EP1S10
6
48
24
6
EP1S20
10
80
40
10
EP1S25
10
80
40
10
EP1S30
12
96
48
12
EP1S40
14
112
56
14
EP1S60
18
144
72
18
EP1S80
22
176
88
22
Device
Maximum 36 × 36
Multipliers
Table 7–2. DSP Block Resources in Stratix GX Devices
DSP Blocks
Maximum 9 × 9
Multipliers
Maximum 18 × 18
Multipliers
Maximum 36 × 36
Multipliers
EP1SGX10C
6
48
24
6
EP1SGX10D
6
48
24
6
EP1SGX25C
10
80
40
10
EP1SGX25D
10
80
40
10
EP1SGX25F
10
80
40
10
EP1SGX40D
14
112
56
14
EP1SGX40G
14
112
56
14
Device
Altera Corporation
September 2004
7–3
Stratix Device Handbook, Volume 2
TriMatrix Memory Overview
Each DSP block supports either eight 9 × 9-bit multipliers, four 18-bit
multipliers, or one 36 × 36-bit multiplier. These multipliers can feed an
adder or an accumulator unit based on the operation mode. Table 7–3
shows the different operation modes for the DSP blocks.
Table 7–3. Operation Modes for DSP Blocks
Number & Size of Multipliers per DSP Block
DSP Block Mode
9 x 9-bit
18 x 18-bit
36 x 36-bit
Simple multiplier
Eight multipliers with
eight product outputs
Four multipliers with four
product outputs
Multiply-accumulate
Two multiply and
accumulate (34 bit)
Two multiply and
accumulate (52 bit)
Two-multipliers adder
4 two-multipliers adders
2 two-multipliers adders
Four-multipliers adder
2 four-multipliers adder
1 four-multipliers adder
One multiplier with one
product output
Implementing multipliers, multiply-adders, and multiply-accumulators
in the DSP blocks has a performance advantage over logic cell
implementation. Using DSP blocks also reduces logic cell and routing
resource consumption. To achieve higher performance, register each
stage of the DSP block to allow pipelining. For implementing
applications, such as FIR filters, efficiently use the input registers of the
DSP block as shift registers.
f
TriMatrix
Memory
Overview
For more information on DSP blocks, see the DSP Blocks in Stratix &
Stratix GX Devices chapter.
Stratix and Stratix GX devices feature the TriMatrix memory structure,
composed of three sizes of embedded RAM blocks. These include the
512-bit size M512 block, the 4-Kbit size M4K block, and the 512-Kbit size
M-RAM block. Each block is configurable to support a wide range of
features.
Tables 7–4 and 7–5 show the number of memory blocks in each Stratix
and Stratix GX device, respectively.
Table 7–4. TriMatrix Memory Resources in Stratix Devices (Part 1 of 2)
Device
M512
M4K
M-RAM
EP1S10
94
60
1
EP1S20
194
82
2
EP1S25
224
138
2
7–4
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Table 7–4. TriMatrix Memory Resources in Stratix Devices (Part 2 of 2)
Device
M512
M4K
M-RAM
EP1S30
295
171
4
EP1S40
384
183
4
EP1S60
574
292
6
EP1S80
767
364
9
Table 7–5. TriMatrix Memory Resources in Stratix GX Devices
Device
M512
M4K
M-RAM
EP1SGX10C
94
60
1
EP1SGX10D
94
60
1
EP1SGX25C
224
138
2
EP1SGX25D
224
138
2
EP1SGX25F
224
138
2
EP1SGX40D
384
183
4
EP1SGX40G
384
183
4
Most DSP applications require local data storage for intermediate
buffering or for filter storage. The TriMatrix memory blocks enable
efficient use of available resources for each application.
The M512 and M4K memory blocks can implement shift registers for
applications, such as multi-channel filtering, auto-correlation, and crosscorrelation functions. Implementing shift registers in embedded memory
blocks reduces logic cell and routing resource consumption.
f
For more information on TriMatrix memory blocks, see the TriMatrix
Embedded Memory Blocks in Stratix & Stratix GX Devices chapter.
DSP Function
Overview
The following sections describe commonly used DSP functions. Each
section illustrates the implementation of a basic DSP building block,
including FIR and IIR filters, in Stratix and Stratix GX devices using DSP
blocks and TriMatrix memory blocks.
Finite Impulse
Response (FIR)
Filters
This section describes the basic theory and implementation of basic FIR
filters, time-domain multiplexed (TDM) FIR filters, and interpolation and
decimation polyphase FIR filters. An introduction to the complex FIR
filter is also presented in this section.
Altera Corporation
September 2004
7–5
Stratix Device Handbook, Volume 2
Finite Impulse Response (FIR) Filters
FIR Filter Background
Digital communications systems use FIR filters for a variety of functions,
including waveform shaping, anti-aliasing, band selection,
decimation/interpolation, and low pass filtering. The basic structure of a
FIR filter consists of a series of multiplications followed by an addition.
The following equation represents an FIR filter operation:
y( n) = x( n) ⊗ h(n )
L–1
y( n) =
∑ x ( n – i )h ( i )
i=0
where:
x(n) represents the sequence of input samples
h(n) represents the filter coefficients
L is the number of filter taps
A sample FIR filter with L=8 is shown in Figure 7–2.
Figure 7–2. Basic FIR Filter
x(n)
h(0)
h(1)
h(2)
h(3)
h(5)
h(4)
h(6)
h(7)
y(n)
This example filter in Figure 7–2 uses the input values at eight different
time instants to produce an output. Hence, it is an 8-tap filter. Each
register provides a unit sample delay. The delayed inputs are multiplied
with their respective filter coefficients and added together to produce the
output. The width of the output bus depends on the number of taps and
the bit width of the input and coefficients.
7–6
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Basic FIR Filter
A basic FIR filter is the simplest FIR filter type. As shown in Figure 7–2, a
basic FIR filter has a single input channel and a single output channel.
Basic FIR Filter Implementation
Stratix and Stratix GX devices’ dedicated DSP blocks can implement basic
FIR filters. Because these DSP blocks have closely integrated multipliers
and adders, filters can be implemented with minimal routing resources
and delays. For implementing FIR filters, the DSP blocks are configured
in the four-multipliers adder mode.
f
See the DSP Blocks in Stratix & Stratix GX Devices chapter for more
information on the different modes of the DSP blocks.
This section describes the implementation of an 18-bit 8-tap FIR filter.
Because Stratix and Stratix GX devices support modularity, cascading
two 4-tap filters can implement an 8-tap filter. Larger FIR filters can be
designed by extending this concept. Users can also increase the number
of taps available per DSP block if 18 bits of resolution are not required. For
example, by using only 9 bits of resolution for input samples and
coefficient values, 8 multipliers are available per DSP block. Therefore, a
9-bit 8-tap filter can be implemented in a single DSP block provided an
external adder is implemented in logic cells.
The four-multipliers adder mode, shown in Figure 7–3, provides four
18 × 18-bit multipliers and three adders in a single DSP block. Hence, it
can implement a 4-tap filter. The data width of the input and the
coefficients is 18 bits, which results in a 38-bit output for a 4-tap filter.
Altera Corporation
September 2004
7–7
Stratix Device Handbook, Volume 2
Finite Impulse Response (FIR) Filters
Figure 7–3. Hardware View of a DSP Block in Four-Multipliers Adder Mode Notes (1). (2), (3)
shiftout
input from
previous
block
shiftout
input from
previous
block
CLK2
CLR2
Data from
row
18
interface
block
Coefficients
18
from row
interface
block
CLK1
CLR1
D
D
Q
Multiplier A
36
D
Q
D
Q
h(0)
Q
Data from row
interface block 18
x(n) 18
18
D
Q
x(n-1) 18
37
36
Coefficients
from row 18
interface
block
Multiplier B
h(1)
D
Q
18
38
38
D
Data from row
interface block 18
D
Q
Output
y(n)
x(n-2) 18
Multiplier C
36
Coefficients
from row 18
interface
block
D
D
Q
D
Q
37
h(2)
Q
Data from row
interface block 18
Q
18
D
Q
x(n-3) 18
36
Coefficients
from row 18
interface
block
D
Q
shiftin
input to
next block
Multiplier D
h(3)
18
shiftin
input to
next block
Notes to Figure 7–3:
(1)
(2)
(3)
The input registers feed the multiplier blocks. These registers can increase the DSP block performance, but are
optional. These registers can also function as shift registers if the dedicated shiftin/shiftout signals are used.
The pipeline registers are fed by the multiplier blocks. These registers can increase the DSP block performance, but
are optional.
The output registers register the DSP block output. These registers can increase the DSP block performance, but are
optional.
7–8
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Figure 7–4. Quartus II Software View of MegaWizard Implementation of a DSP Block in Four-Multipliers
Adder Mode
Each input register of the DSP block provides a shiftout output that
connects to the shiftin input of the adjacent input register of the same DSP
block. The registers on the boundaries of a DSP block also connect to the
registers of adjacent DSP blocks through the use of shiftin/shiftout
connections. These connections create register chains spanning multiple
DSP blocks, which makes it easy to increase the length of FIR filters.
Figure 7–5 shows two DSP blocks connected to create an 8-tap FIR filter.
Filters with more taps can be implemented by connecting DSP blocks in
a similar manner, provided sufficient DSP blocks are available in the
device.
1
Adding the outputs of the two DSP blocks requires an external
adder which can be implemented using logic cells.
The input data can be fed directly or by using the shiftout/shiftin chains,
which allow a single input to shift down the register chain inside the DSP
block. The input to each of the registers has a multiplexer, hence, the data
can be fed either from outside the DSP block or the preceding register.
This can be selected from the MegaWizard® in the Quartus® II software,
as shown in Figure 7–4. The example in Figure 7–5 uses the
shiftout/shiftin flip-flop chains where the multiplexers are configured to
use these chains. In this example, the flip-flops inside the DSP blocks
serve as the taps of the FIR filter.
Altera Corporation
September 2004
7–9
Stratix Device Handbook, Volume 2
Finite Impulse Response (FIR) Filters
When the coefficients are loaded in parallel, they can be fed directly from
memory elements or any other muxing scheme. This facilitates the
implementation of an adaptive (variable) filter.
Further, if the user wants to implement the shift register chains external
to the DSP block, this can be done by using the altshift_taps
megafunction. In this case, the coefficient and data shifting is done
external to the DSP block. The DSP block is only used to implement the
multiplications and the additions.
Parallel vs. Serial Implementation
The fastest implementations are fully parallel, but consume more logic
resources than serial implementations. To trade-off performance for logic
resources, implement a serial scheme with a specified number of taps. To
facilitate this, Altera provides the FIR Compiler core through its
MegaCore program. The FIR Compiler is an easy-to-use, fully-integrated
graphical user interface (GUI) based FIR filter design software.
f
For more information on the FIR Compiler MegaCore, visit the Altera
web site at www.altera.com and search for “FIR compiler” in the
“Intellectual Property” page.
It is important to note that the four-multipliers adder mode allows a DSP
block to be configured for parallel or serial input. When it is configured
for parallel input, as shown in Figure 7–6, the data input and the
coefficients can be loaded directly without the need for shiftin/shiftout
chains between adjacent registers in the DSP block. When the DSP block
is configured for serial input, as shown in Figure 7–5, the shiftin/shiftout
chains create a register cascade both within the DSP block and also
between adjacent DSP blocks.
7–10
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Figure 7–5. Serial Loading 18-Bit 8-Tap FIR Filter Using Two DSP Blocks
Notes (1), (2), (3)
Data input x(n)
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
DSP block 1
Filter coefficients h(0)
x
x(n-1)
h(1)
x
x(n-2)
h(2)
x
x(n-3)
h(3)
Filter output
y(n)
x
x(n-4)
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
DSP block 2
h(4)
x
x(n-5)
h(5)
x
x(n-6)
h(6)
x
x(n-7)
h(7)
Notes to Figure 7–5:
(1)
(2)
(3)
Altera Corporation
September 2004
Unused ports grayed out.
The indexing x(n-1), ..., x(n-7) refers to the case of parallel loading and should be
ignored here. This indexing is retained in this figure for consistency with other
figures in this chapter.
To increase the DSP block performance, include the pipeline and output registers.
See Figure 7–3 on page 7–8 for the details.
7–11
Stratix Device Handbook, Volume 2
Finite Impulse Response (FIR) Filters
Figure 7–6. Parallel Loading 18-Bit 8-Tap FIR Filter Using Two DSP Blocks
Notes (1), (2)
Data input x(n)
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
DSP block 1
Filter coefficients h(0)
x(n-1)
h(1)
x(n-2)
h(2)
x(n-3)
h(3)
Filter output
y(n)
x(n-4)
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
DSP block 2
h(4)
x(n-5)
h(5)
x(n-6)
h(6)
x(n-7)
h(7)
Notes to Figure 7–6:
(1)
(2)
The indexing x(n-1), ..., x(n-7) refers to the case of parallel loading.
To increase the DSP block performance, include the input, pipeline, and output
registers. See Figure 7–3 on page 7–8 for the details.
7–12
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Basic FIR Filter Implementation Results
Table 7–6 shows the results of the serial implementation of an 18-bit 8 tap
FIR filter as shown in Figure 7–5 on page 7–11
Table 7–6. Basic FIR Filter Implementation Results
Part
EP1S10F780
Utilization
LCELL: 130/10570 (1%)
DSP Block 9-bit elements: 16/48 (33%)
Memory bits: 288/920448 (<1%)
Performance
247 MHz
Basic FIR Filter Design Example
Download the Basic FIR Filter (base_fir.zip) design example from the
Design Examples section of the Altera web site at www.altera.com.
Time-Domain Multiplexed FIR Filters
A TDM FIR filter is clocked n-times faster than the sample rate in order to
reuse the same hardware. Consider the 8-tap filter shown in Figure 7–2.
The TDM technique can be used with a TDM factor of 2, i.e., n = 2, to
implement this filter using only four multipliers, provided the filter is
clocked two times faster internally.
To understand this concept, consider Figure 7–7 that shows a TDM filter
with a TDM factor of 2. A 2× -multiplied clock is required to run the filter.
On cycle 0 of the 2× clock, the user loads four coefficients into the four
multiplier inputs. The resulting output is stored in a register. On cycle 1
of the 2× clock, the user loads the remaining four coefficients into the
multiplier inputs. The output of cycle 1 is added with the output of cycle
0 to create the overall output. See the “TDM Filter Implementation” on
page 7–14 section for details on the coefficient loading schedule.
The TDM implementation shown in Figure 7–7 requires only four
multipliers to achieve the functionality of an 8-tap filter. Thus, TDM is a
good way to save logic resources, provided the multipliers can run at ntimes the clock speed. The coefficients can be stored in ROM/RAM, or
any other muxing scheme.
Altera Corporation
September 2004
7–13
Stratix Device Handbook, Volume 2
Finite Impulse Response (FIR) Filters
Figure 7–7. Block Diagram of 8-Tap FIR Filter with TDM Factor of n=2
Output
FIR filter with
four multipliers
18-bit input
D
Q
2x clock
TDM Filter Implementation
TDM FIR filters are implemented in Stratix and Stratix GX devices by
configuring the DSP blocks in the multiplier-adder mode. Figure 7–9
shows the implementation of an 8-tap TDM FIR filter (n=2) with 18 bits
of data and coefficient inputs. Because the input data needs to be loaded
into the DSP block in parallel, a shift register chain is implemented using
a combination of logic cells and the altshift_taps function. This shift
register is clocked with the same data sample rate (clock 1× ). The filter
coefficients are stored in ROM and loaded into the DSP block in parallel
as well. Because the TDM factor is 2, both the ROM and DSP block are
clocked with clock 2× .
Table 7–7. Operation of TDM Filter (Shown in Figure 7–9 on page 7–16)
Cycle of
2× Clock
Cycle Output
0
y0 = x(n-1)h(1) + x(n-3)h(3) + x(n-5)h(5) + x(n-7)h(7)
Store result
N/A
1
y1 = x(n)h(0)
+ x(n-2)h(2) + x(n-4)h(4) + x(n-6)h(6)
Generate output
y(n) = y0 + y1
2
y2 = x(n)h(1)
+ x(n-2)h(3) + x(n-4)h(5) + x(n-6)h(7)
Store result
N/A
3
y3 = x(n+1)h(0) + x(n-1)h(2) + x(n-3)h(4) + x(n-5)h(6)
Generate output
y(n) = y2 + y3
4
y4 = x(n+1)h(1) + x(n-1)h(3) + x(n-3)h(5) + x(n-5)h(7)
Store result
N/A
5
y5 = x(n+2)h(0) + x(n)h(2)
Generate output
y(n) = y4 + y5
6
y6 = x(n+2)h(1) + x(n)h(3) + x(n-2)h(5) + x(n-4)h(7)
Store result
N/A
7
y7 = x(n+3)h(0) + x(n+1)h(2) + x(n-1)h(4) + x(n-3)h(6) Generate output
+ x(n-2)h(4) + x(n-4)h(6)
Operation
Overall Output,
y(n)
y(n) = y6 + y7
Figure 7–8 and Table 7–7 show the coefficient loading schedule. For
example, during cycle 0, only the flip-flops corresponding to h(1), h(3),
h(5), and h(7) are enabled. This produces the temporary output, y0, which
is stored in a flip-flop outside the DSP block. During cycle 1, only the flip-
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
flops corresponding to h(0), h(2), h(4) and h(6) are enabled. This produces
the temporary output, y1, which is added to y0 to produce the overall
output, y(n). The following shows what the overall output, y(n), equals:
y ( n ) = y0 + y1
y ( n ) = x ( 0 )h ( 0 ) + x ( n – 1 )h ( 1 ) + x ( n – 2 )h ( 2 ) + x ( n – 3 )h ( 3 )
+ x ( n – 4 )h ( 4 ) + x ( n – 5 )h ( 5 ) + x ( n – 6 )h ( 6 ) + x ( n – 7 )h ( 7 )
This is identical to the output of the 8-tap filter shown in Figure 7–2. After
cycle 1, this process is repeated at every cycle.
Figure 7–8. Coefficient Loading Schedule in a TDM Filter
2x clock
1x clock
Cycle 0
Cycle 1
Cycle 2
Cycle 3
load h(1), h(3), h(5), h(7) load h(0), h(2), h(4), h(6) load h(1), h(3), h(5), h(7) load h(0), h(2), h(4), h(6)
Altera Corporation
September 2004
Cycle 4
load h(1), h(3), h(5), h(7)
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Finite Impulse Response (FIR) Filters
Figure 7–9. TDM FIR Filter Implementation Note (1)
Data input
x
x(n)
Shift register
DSP block
D
Q
D
Q
D
Q
D
Q
D
Q
Filter coefficients
D
Q
D
Q
D
Q
RAM / ROM 0
RAM / ROM 1
Accumulator
D
D
Q
D
Q
D
Q
RAM / ROM 2
RAM / ROM 3
D
Q
D
Q
D
Q
D
Q
Q
Filter output
y(n)
1x clock
Clock input
(1x clock)
PLL
2x clock
Note to Figure 7–9:
(1)
To increase the DSP block performance, include the pipeline and output registers. See Figure 7–3 on page 7–8 for
details.
If the TDM factor is more than 2, then a multiply-accumulator needs to be
implemented. This multiply-accumulator can be implemented using the
soft logic outside the DSP block if all the multipliers of the DSP block are
needed. Alternatively, the multiply-accumulator may be implemented
inside the DSP block if all the multipliers of the DSP block are not needed.
The accumulator needs to be zeroed at the start of each new sample input.
The user also needs a way to store additional sample inputs in memory.
For example, consider a sample rate of r and TDM factor of 4. Then, the
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
user needs a way to accept this sample data and send it at a 4r rate to the
input of the DSP block. One way to do this is using a first-in-first-out
(FIFO) memory with input clocked at rate r and output clocked at rate 4r.
The FIFO may be implemented in the TriMatrix memory.
TDM Filter Implementation Results
Table 7–8 shows the results of the implementation of an 18-bit 8-tap TDM
FIR filter as shown in Figure 7–9 on page 7–16.
Table 7–8. TDM Filter Implementation Results
Part
EP1S10F780
Utilization
Lcell: 196/10570 (1%)
DSP Block 9-bit elements: 8/48 (17%)
Memory bits: 360/920448 (<1%)
Performance
240 MHz (1)
Note to Table 7–8:
(1)
This refers to the performance of the DSP blocks. The input and output rate is 120
million samples per second (MSPS), clocked in and out at 120 MHz.
TDM Filter Design Example
Download the TDM FIR Filter (tdm_fir.zip) design example from the
Design Examples section of the Altera web site at www.altera.com.
Polyphase FIR Interpolation Filters
An interpolation filter can be used to increase sample rate. An
interpolation filter is efficiently implemented with a polyphase FIR filter.
DSP systems frequently use polyphase filters because they simplify
overall system design and also reduce the number of computations per
cycle required of the hardware. This section first describes interpolation
filters and then how to implement them as polyphase filters in Stratix and
Stratix GX devices. See the “Polyphase FIR Decimation Filters” on
page 7–24 section for a discussion of decimation filters.
Interpolation Filter Basics
An interpolation filter increases the output sample rate by a factor of I
through the insertion if I-1 zeros between input samples, a process
known as zero padding. After the zero padding, the output samples in
time domain are separated by Ts/I = 1/(I× fs), where Ts and fs are the
sample period and sample frequency of the original signal, respectively.
Figure 7–10 shows the concept of signal interpolation.
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September 2004
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Finite Impulse Response (FIR) Filters
Inserting zeros between the samples creates reflections of the original
spectrum, thus, a low pass filter is needed to filter out the reflections.
Figure 7–10. Block Diagram Representation of Interpolation
Input
sample rate fs
I
LPF
Output
sample rate I*fs
To see how interpolation filters work, consider the Nyquist Sampling
Theorem. This theorem states that the maximum frequency of the input
to be sampled must be smaller than fs/2, where fs is the sampling
frequency, to avoid aliasing. This frequency, fs/2, is also known as the
Nyquist frequency (Fn). Typically, before a signal is sampled using an
analog to digital converter (ADC), it needs to be low pass filtered using
an analog anti-aliasing filter to prevent aliasing. If the input frequency
spectrum extends close to the Nyquist frequency, then the first alias is also
close to the Nyquist frequency. Therefore, the low pass filter needs to be
very sharp to reject this alias. A very sharp analog filter is hard to design
and manufacture and could increase passband ripple, thereby
compromising system performance.
The solution is to increase the sampling rate of the ADC, so that the new
Nyquist frequency is higher and the spacing between the desired signal
and the alias is also higher. Zero padding as described above increase the
sample rate. This process also known as upsampling (oversampling)
relaxes the roll off requirements of the anti-aliasing filter. Consequently, a
simpler filter achieves alias suppression. A simpler analog filter is easier
to implement, does not compromise system performance, and is also
easier to manufacture.
Similarly, the digital to analog converter (DAC) typically interpolates the
data before the digital to analog conversion. This relaxes the requirement
on the analog low pass filter at the output of the DAC.
The interpolation filter does not need to run at the oversampled
(upsampled) rate of fs× I. This is because the extra sample points added
are zeros, so they do not contribute to the output.
Figure 7–11 shows the time and frequency domain representation of
interpolation for a specific case where the original signal spectrum is
limited to 2 MHz and the interpolation factor (I) is 4. The Nyquist
frequency of the upsampled signal must be greater than 8 MHz, and is
chosen to be 9 MHz for this example.
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Figure 7–11. Time & Frequency Domain Representations of Interpolation for I = 4
As an example, CD players use interpolation, where the nominal sample
rate of audio input is 44.1 kilosamples per second. A typical
implementation might have an interpolation (oversampling) factor of 4
generating 176.4 kilosamples per second of oversampled data stream.
Polyphase Interpolation Filters
A direct implementation of an interpolation filter, as shown in
Figure 7–10, imposes a high computational burden. For example, if the
filter is 16 taps long and a multiplication takes one cycle, then the number
of computations required per cycle is 16× I. Depending on the
interpolation factor (I), this number can be quite big and may not be
achievable in hardware. A polyphase implementation of the low pass
filter can reduce the number of computations required per cycle, often by
a large factor, as will be evident later in this section.
The polyphase implementation “splits” the original filter into I
polyphase filters whose impulse responses are defined by the following
equation:
h k ( n ) = h ( k + nI )
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September 2004
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Finite Impulse Response (FIR) Filters
where:
k = 0,1, …, I-1
n = 0,1, …, P-1
P = L/I = length of polyphase filters
L = length of the filter (selected to be a multiple of I)
I = interpolation factor
h(n) = original filter impulse response
This equation implies that the first polyphase filter, h0(n), has coefficients
h(0), h(I), h(2I),..., h((P-1)I). The second polyphase filter, h1(n), has
coefficients h(1), h(1+I), h(1+2I), ..., h(1+(P-1)I). Continuing in this way,
the last polyphase filter, hI-1(n), has coefficients h(I-1), h((I - 1) + N), h((I
- 1) + 2I), ..., h((I - 1) + (P-1)I).
An example helps in understanding the polyphase implementation of
interpolation. Consider the polyphase representation of a 16-tap low pass
filter with an interpolation factor of 4. Thus, the output is given below:
15
y( n) =
∑ h ( n – iI )x ( i )
i=0
Referring back to Figure 7–11 on page 7–19, the only nonzero samples of
the input are x(0), x(4), x(8,) and x(12). The first output, y(0), only depends
on h(0), h(4), h(8) and h(12) because x(i) is zero for i ≠ 0, 4, 8, 12. Table 7–9
shows the coefficients required to generate output samples.
Table 7–9. Decomposition of a 16-Tap Interpolating Filter into Four Polyphase Filters
Output Sample
Coefficients Required
Polyphase Filter Impulse Response
y(0), y(4)...
h(0), h(4), h(8), h(12)
h0(n)
y(1), y(5)...
h(1), h(5), h(9), h(13)
h1(n)
y(2), y(6)...
h(2), h(6), h(10), h(14)
h2(n)
y(3), y(7)...
h(3), h(7), h(11), h(15)
h3(n)
Table 7–9 shows that this filter operation can be represented by four
parallel polyphase filters. This is shown in Figure 7–12. The outputs from
the filters are multiplexed to generate the overall output. The multiplexer
is controlled by a counter, which counts up modulo-I starting at 0.
It is illuminating to compare the computational requirements of the direct
implementation versus polyphase implementation of the low pass filter.
In the direct implementation, the number of computations per cycle
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
required is 16 × I = 16 × 4 = 64. In the polyphase implementation, the
number of computations per cycle required is 4 × 4 = 16. This is because
there are four polyphase filters, each with four taps.
Figure 7–12. Polyphase Representation of I=4 Interpolation Filter
Interpolation Using a Single Low-Pass Filter
Input
x(n)
I=4
Output
y(n)
LPF with
coefficients
h(0), h(1), ... h(15)
Interpolation Using a Polyphase Filter
Polyphase filter
with coefficients
h(0), h(4), h(8), h(12)
Polyphase filter
with coefficients
h(1), h(5), h(9), h(13)
Input
x(n)
y1(n)
0
1
2
3
Output
y(n)
y2(n)
Polyphase filter
with coefficients
h(2), h(6), h(10), h(14) y3(n)
Polyphase filter
with coefficients
h(3), h(7), h(11), h(15) y4(n)
4x Clock
Modulo 4 up
counter
initialized at 0
Polyphase Interpolation Filter Implementation
Figure 7–13 shows the Stratix or Stratix GX implementation of the
polyphase interpolation filter in Figure 7–12. The four polyphase filters
share the same hardware, which is a 4-tap filter. One Stratix or Stratix GX
DSP block can implement one 4-tap filter with 18-bit wide data and
coefficients. A multiplexer can be used to load new coefficient values on
every cycle of the 4× clock. Stratix and Stratix GX phase lock loops (PLLs)
can generate the 4× clock. In the first cycle of the 4× clock, the user needs
to load coefficients for polyphase filter h0(n); in the second cycle of the 4×
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September 2004
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Finite Impulse Response (FIR) Filters
clock, the users needs to load coefficients of the polyphase filter h1(n) and
so on. Table 7–10 summarizes the coefficient loading schedule. The
output, y(n), is clocked using the 4× clock.
Table 7–10. Polyphase Interpolation (I=4) Filter Coefficient Loading
Schedule
Cycle of 4× Clock
Coefficients to Load
1, 5,...
h(0), h(4), h(8), h(12)
0, 1, 2, 3
2, 6,...
h(1), h(5), h(9), h(13)
0, 1, 2, 3
3, 7,...
h(2), h(6), h(10), h(14)
0, 1, 2, 3
4, 8,...
h(3), h(7), h(11), h(15)
0, 1, 2, 3
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Corresponding RAM/ROM
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Figure 7–13. Implementation of the Polyphase Interpolation Filter (I=4) Notes (1), (2), (3)
Data input
x
x(n)
DSP block
D
Q
D
Q
D
Q
D
Q
Filter coefficients
h(0)
RAM / ROM 0
h(1)
RAM / ROM 1
Filter output
y(n)
D
Q
D
Q
D
Q
D
Q
h(2)
RAM / ROM 2
h(3)
RAM / ROM 3
Note (1)
Clock input
(1x clock)
Note (2)
1x clock
PLL
4x clock
Notes to Figure 7–13:
(1)
(2)
(3)
The 1× clock feeds the input data shiftin register chain.
The 4× clock feeds the input registers for the filter coefficients and other optional registers in the DSP block. See
Note (3).
To increase the DSP block performance, include the pipeline, and output registers. See Figure 7–3 for the details.
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September 2004
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Finite Impulse Response (FIR) Filters
Polyphase Interpolation Filter Implementation Results
Table 7–11 shows the results of the polyphase interpolation filter
implementation in a Stratix device shown in Figure 7–13.
Table 7–11. Polyphase Interpolation Filter Implementation Results
Part
EP1S10F780
Utilization
Lcell: 3/10570 (<1%)
DSP Block 9-bit elements: 8/48 (17%)
Memory bits: 288/920448 (<1%)
Performance
240 MHz (1)
Note to Table 7–11:
(1)
This refers to the performance of the DSP blocks, as well as the output clock rate.
The input rate is 60 MSPS, clocked in at 60MHz.
Polyphase Interpolation Filter Design Example
Download the Interpolation FIR Filter (interpolation_fir.zip) design
example from the Design Examples section of the Altera web site at
www.altera.com.
Polyphase FIR Decimation Filters
A decimation filter can be used to decrease the sample rate. A decimation
filter is efficiently implemented with a polyphase FIR filter. DSP systems
frequently use polyphase filters because they simplify overall system
design and also reduce the number of computations per cycle required of
the hardware. This section first describes decimation filters and then how
to implement them as polyphase filters in Stratix devices. See the
“Polyphase FIR Interpolation Filters” section for a discussion of
interpolation filters.
Decimation Filter Basics
A decimation filter decreases the output sample rate by a factor of D
through keeping only every D-th input sample. Consequently, the
samples at the output of the decimation filter are separated by D× Ts=
D/fs, where Ts and fs are the sample period and sample frequency of the
original signal, respectively. Figure 7–14 shows the concept of signal
decimation.
The signal needs to be low pass filtered before downsampling can begin
in order to avoid the reflections of the original spectrum from being
aliased back into the output signal.
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September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Figure 7–14. Block Diagram Representation of Decimation
Input
sample rate fs
LPF
D
Output
sample rate fs/D
Decimation filters reverse the effect of the interpolation filters. Before the
decimation process, a low pass filter is applied to the signal to attenuate
noise and aliases present beyond the Nyquist frequency. The filtered
signal is then applied to the decimation filter, which processes every D-th
input. Therefore the values between samples D, D-1, D-2 etc. are ignored.
This allows the filter to run M times slower than the input data rate.
In a typical system, after the analog to digital conversion is complete, the
data needs to be filtered to remove aliases inherent in the sampled data.
Further, at this point there is no need to continue to process this data at
the higher sample (oversampled) rate. Therefore, a decimation FIR filter
at the output of the ADC lowers the data rate to a value that can be
processed digitally.
Figure 7–15 shows a specific example where a signal spread over 8 MHz
is decimated by a factor of 4 to 2 MHz. The Nyquist frequency of the
downsampled signal must be greater than 2 MHz, and is chosen to be
2.25 MHz in this example.
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September 2004
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Finite Impulse Response (FIR) Filters
Figure 7–15. Time & Frequency Domain Representations of Decimation for D=4
Polyphase Decimation Filters
Figure 7–14 shows a direct implementation of a decimation filter, which
imposes a high computational burden. For example, if the filter is 16 taps
long and a multiplication takes one cycle, the number of computations
required per cycle is 16× D. Depending on the decimation factor (D), this
number can be quite big and may not be achievable in hardware. A
polyphase implementation of the low pass filter can reduce the number
of computations required, often by a large ratio, as will be evident later in
this section.
The polyphase implementation “splits” the original filter into D
polyphase filters with impulse responses defined by the following
equation.
h k ( n ) = h ( k + nD )
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
where:
k = 0,1, …, D-1
n = 0,1, …, P-1
P = L/D = length of polyphase filters
L is the length of the filter (selected to be a multiple of D)
D is the decimation factor
h(n) is the original filter impulse response
This equation implies that the first polyphase filter, h0(n), has coefficients
h(0), h(D), h(2D)…h((P-1)D). The second polyphase filter, h1(n), has
coefficients h(1), h(1+D), h(1+2D), ..., h(1+(P-1)D). Continuing in this way,
the last polyphase filter, hD-1(n) has coefficients h(D-1), h((D - 1) + D),
h((D - 1) + 2D), ..., h((D - 1) + (P-1)D).
An example helps in the understanding of the polyphase implementation
of decimation. Consider the polyphase representation of a 16-tap low
pass filter with a decimation factor of 4. The output is given by:
15
y( n) =
∑ h ( i )x ( nD – i )
i=0
Referring to Figure 7–15 on page 7–26, it is clear that the output, y(n) is
discarded for n ≠ 0, 4, 8, 12, hence the only values of y(n) that need to be
computed are y(0), y(4), y(8), y(12). Table 7–12 shows which coefficients
are required to generate the output samples.
Table 7–12. Decomposition of a 16-Tap Decimation Filter into Four Polyphase Filters
Output Sample (1)
Coefficients Required
Polyphase Filter Impulse Response
y(0)0, y(4)0, . . .
h(0), h(4), h(8), h(12)
h0(n)
y(0)1, y(4)1, . . .
h(1), h(5), h(9), h(13)
h1(n)
y(0)2, y(4)2, . . .
h(2), h(6), h(10), h(14)
h2(n)
y(0)3, y(4)3, . . .
h(3), h(7), h(11), h(15)
h3(n)
Note to Table 7–12:
(1)
The output sample is the sum of the results from four polyphase filters: y(n) = y(n)0 + y(n)1 + y(n)2 + y(n)3.
Table 7–12 shows that the overall decimation filter operation can be
represented by 4 parallel polyphase filters. Figure 7–16 shows the
polyphase representation of the decimation filter. A demultiplexer at the
input ensures that the input is applied to only one polyphase filter at a
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September 2004
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Finite Impulse Response (FIR) Filters
time. The demultiplexer is controlled by a counter, which counts down
modulo-D starting at 0. The overall output is taken by adding the outputs
of all the filters.
The polyphase representation of the decimation filter also reduces the
computational requirement. For the example in Figure 7–16, the direct
implementation requires 16 × D = 16 × 4 = 64 computations per cycle,
whereas the polyphase implementation requires only 4 × 4 × 1 = 16
computations per cycle. This saving in computational complexity is quite
significant and is often a very convincing reason to use polyphase filters.
Figure 7–16. Polyphase Filter Representation of a D=4 Decimation Filter
Decimation Using a Single Low-Pass Filter
Input
x(n)
LPF with
coefficients
h(0), h(1), ... h(15)
D=4
Output
y(n)
Decimation Using a Polyphase Filter
Input
x(n)
0
1
2
3
Polyphase filter
with coefficients
h(0), h(4), h(8), h(12)
Output
y(n)
Polyphase filter
with coefficients
h(1), h(5), h(9), h(13)
Polyphase Filter
with coefficients
h(2), h(6), h(10), h(14)
Polyphase Filter
with coefficients
h(3), h(7), h(11), h(15)
4x clock
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Modulo 4 down
counter
initialized at 0
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Polyphase Decimation Filter Implementation
Figure 7–17 shows the decimation polyphase filter example of
Figure 7–16 as it would fit into Stratix or Stratix GX DSP blocks. The
coefficients of the polyphase filters need to be cycled using the schedule
shown in Table 7–13. The output y(n), is clocked using the 1× clock.
Table 7–13. Coefficient Loading Schedule for Polyphase Decimation Filter
(D=4)
Cycle of 4× Clock
Altera Corporation
September 2004
Coefficients to Load
Corresponding RAM/ROM
1, 5,...
h(0), h(4), h(8), h(12)
0, 1, 2, 3
2, 6,...
h(3), h(7), h(11), h(15)
0, 1, 2, 3
3, 7,...
h(2), h(6), h(10), h(14)
0, 1, 2, 3
4, 8,...
h(1), h(5), h(9), h(13)
0, 1, 2, 3
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Finite Impulse Response (FIR) Filters
Figure 7–17. Implementation of the Polyphase Decimation Filter (D=4) Notes (1), (2), (3)
Data input
x
x(n)
D
DSP block
Q
D
D
D
D
Q
Q
ROM
D
Q
Filter output
y(n)
Q
D
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
Q
Q
ROM
Q
Note (2)
Clock input
(1x clock)
Q
Q
D
D
Q
Q
ROM
D
D
Q
D
D
Q
Filter
coefficients
ROM
Q
D
D
Q
D
Note (1)
4x clock
PLL
1x clock
Notes to Figure 7–17:
(1)
(2)
(3)
The 1× clock feeds the register after the accumulator block.
The 4× clock feeds the shift register for the data, the input registers for both the data and filter coefficients, the other
optional registers in the DSP block (see Note (3)), and the accumulator block.
To increase the DSP block performance, include the pipeline, and output registers. See Figure 7–3 on page 7–8 for
the details.
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Polyphase Decimation Filter Implementation Results
Table 7–14 shows the results of the polyphase decimation filter
implementation in a Stratix device shown in Figure 7–17.
Table 7–14. Polyphase Decimation Filter Implementation Results
Part
EP1S10F780
Utilization
Lcell: 168/10570 (1%)
DSP Block 9-bit elements: 8/48 (17%)
Memory bits: 300/920448(<1%)
Performance
240 MHz (1)
Note to Table 7–14:
(1)
This refers to the performance of the DSP blocks, as well as the input clock rate.
The output rate is 60 MSPS (clocked out at 60MHz).
Polyphase Decimation Filter Design Example
Download the Decimation FIR Filter (decimation_fir.zip) design
example from the Design Examples section of the Altera web site at
www.altera.com.
Complex FIR Filter
A complex FIR filter takes real and imaginary input signals and performs
the filtering operation with real and imaginary filter coefficients. The
output also consists of real and imaginary signals. Therefore, a complex
FIR filter is similar to a regular FIR filter except for the fact that the input,
output, and coefficients are all complex numbers.
One example application of complex FIR filters is equalization. Consider
a Phase Shift Keying (PSK) system; a single complex channel can
represent the I and Q data channels. A FIR filter with complex coefficients
could then process both data channels simultaneously. The filter
coefficients are chosen in order to reverse the effects of intersymbol
interference (ISI) inherent in practical communication channels. This
operation is called equalization. Often, the filter is adaptive, i.e. the filter
coefficients can be varied as desired, to optimize performance with
varying channel characteristics.
A complex variable FIR filter is a cascade of complex multiplications
followed by a complex addition. Figure 7–18 shows a block diagram
representation of a complex FIR filter. To compute the overall output of
the FIR filter, it is first necessary to determine the output of each complex
multiplier. This can be expressed as:
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Finite Impulse Response (FIR) Filters
y real = x real × h real – x imag × h imag
y imag = x real × h imag + h real × x imag
where:
xreal is the real input signal
ximag is the imaginary input signal
hreal is the real filter coefficients
himag is the imaginary filter coefficients
yreal is the real output signal
yimag is the imaginary output signal
In complex representation, this equals:
y real + jy imag = ( x real + jx imag ) × ( h real + jh imag )
The overall real channel output is obtained by adding the real channel
outputs of all the multipliers. Similarly, the overall imaginary channel
output is obtained by adding the imaginary channel outputs of all the
multipliers.
Figure 7–18. Complex FIR Filter Block Diagram
xreal
ximag
Complex
FIR filter
hreal
yreal
yimag
himag
Complex FIR Filter Implementation
Complex filters can be easily implemented in Stratix devices with the DSP
blocks configured in the two-multipliers adder mode. One DSP block can
implement a 2-tap complex FIR filter with 9-bit inputs, or a single tap
complex FIR filter with 18-bit inputs. DSP blocks can be cascaded to
implement complex filters with more taps.
1
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The two-multipliers adder mode has two adders, each adding
the outputs of two multipliers. One of the adders is configured
as a subtractor.
Altera Corporation
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
f
For more information on the different modes of the DSP blocks, see the
DSP Blocks in Stratix & Stratix GX Devices chapter.
Figure 7–19 shows an example of a 2-tap complex FIR filter design with
18-bit inputs. The real and the complex outputs of the DSP blocks are
added externally to generate the overall real and imaginary output. As in
the case of basic, TDM, or polyphase FIR filters, the coefficients may be
loaded in series or parallel.
Figure 7–19. 2-Tap 18-Bit Complex FIR Filter Implementation
DSP block
Configured as a subtractor
xreal1
outreal1 = xreal1 * hreal1 - ximag1 * himag1
ximag1
Configured as a adder
Overall real output
hreal1
outimag1 = xreal1 * himag1 + ximag1 * hreal1
himag1
DSP block
Configured as a subtractor
xreal2
outreal2 = xreal2 * hreal2 - ximag2 * himag2
ximag2
Overall imaginary output
Configured as a adder
hreal2
outimag2 = xreal2 * himag2 + ximag2 * hreal2
himag2
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September 2004
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Infinite Impulse Response (IIR) Filters
Infinite Impulse
Response (IIR)
Filters
Another class of digital filters are IIR filters. These are recursive filters
where the current output is dependent on previous outputs. In order to
maintain stability in an IIR filter, careful design consideration must be
given, especially to the effects of word-length to avoid unbounded
conditions. The following section discusses the general theory and
applications behind IIR Filters.
IIR Filter Background
The impulse response of an IIR filter extends for an infinite amount of
time because their output is based on feedback from previous outputs.
The general expression for IIR filters is:
n
y( n) =
n
∑ a ( i )x ( n – i ) – ∑ b ( i )y ( n – i )
i=0
i=1
where ai and bi represent the coefficients in the feed-forward path and
feedback path, respectively, and n represents the filter order. These
coefficients determine where the poles and zeros of the IIR filter lie.
Consequently, they also determine how the filter functions (i.e., cut-off
frequencies, band pass, low pass, etc.).
The feedback feature makes IIR filters useful in high data throughput
applications that require low hardware usage. However, feedback also
introduces complications and caution must be taken to make sure these
filters are not exposed to situations in which they may become unstable.
The complications include phase distortion and finite word length effects,
but these can be overcome by ensuring that the filter always operates
within its intended range.
Figure 7–20 shows a direct form II structure of an IIR filter.
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September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Figure 7–20. Direct Form II Structure of an IIR Filter
w(n)
Σ
X(n)
Z
Σ
-b1
Σ
-b2
Σ
-bn
Z
Z
a0
Σ
a1
Σ
a2
Σ
an
Σ
Y(n)
-1
-1
-1
The transfer function for an IIR filter is:
n
∑ ai z
–i
i=0
H ( z ) = -----------------------------n
1+
∑ bi z
–i
i=1
The numerator contains the zeros of the filter and the denominator
contains the poles. The IIR filter structure requires a multiplication
followed by an accumulation. Constructing the filter directly from the
transfer function shown above may result in finite word length
limitations and make the filter potentiality unstable. This becomes more
critical as the filter order increases, because it only has a finite number of
bits to represent the output. To prevent overflow or instability, the
transfer function can be split into two or more terms representing several
second order filters called biquads. These biquads can be individually
scaled and cascaded, splitting the poles into multiples of two. For
example, an IIR filter having ten poles should be split into five biquad
sections. Doing this minimizes quantization and recursive accumulation
errors.
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Infinite Impulse Response (IIR) Filters
This cascaded structure rearranges the transfer function. This is shown in
the equation below, where each product term is a second order IIR filter.
If n is odd, the last product term is a first order IIR filter:
(n + 1) ⁄ 2
H(z) = C ×
∏
k=1
–1
–2
a 0k + a 1k z + a 2k z
--------------------------------------------------- = C×
–1
–2
1 + b 1k z + b 2k z
(n + 1) ⁄ 2
∏
Hk ( z )
k=1
Figure 7–21 shows the cascaded structure.
Figure 7–21. Cascaded IIR Filter
x(n)
C
H 1 (z)
H k (z)
H n (z)
y(n)
Basic IIR Filters
In this section, the basic IIR filter is implemented using cascaded second
order blocks or biquads in the direct form II structure.
Basic IIR FIlter Implementation
Multiplier blocks, adders and delay elements can implement a basic IIR
filter. The Stratix architecture lends itself to IIR filters because of its
embedded DSP blocks, which can easily be configured to perform these
operations. The altmult_add megafunction can be used to implement
the multiplier-adder mode in the DSP blocks. Figure 7–22 shows the
implementation of an individual biquad using Stratix and Stratix GX DSP
blocks.
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Figure 7–22. IIR Filter Biquad Note (1)
Note to Figure 7–22:
(1)
Altera Corporation
September 2004
Unused ports are grayed out.
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Infinite Impulse Response (IIR) Filters
The first DSP block in Figure 7–22 is configured in the two-multipliers
adder mode, and the second DSP block is in the four-multipliers adder
mode. For an 18-bit input to the IIR filter, each biquad requires five
multipliers and five adders (two DSP blocks). One of the adders is
implemented using logic elements. Cascading several biquads together
can implement more complex, higher order IIR filters. It is possible to
insert registers in between the biquad stages to improve the performance.
Figure 7–23 shows a 4thorder IIR filter realized using two cascaded
biquads in three DSP blocks.
Figure 7–23. Two Cascaded Biquads
First
biquad
a10
a11
Four-multipliers
adder mode
a12
DSP
block 1
b11
b12
x[n]
Two-multipliers
adder mode
b21
b22
a20
DSP
block 2
Four-multipliers
adder mode
Second
biquad
y[n]
a21
a22
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DSP
block 3
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Basic IIR Filter Implementation Results
Table 7–15 shows the results of implementing a 4th order IIR filter in a
Stratix device.
Table 7–15. 4th Order IIR Filter Implementation Results
Part
EP1S10F780C5
Utilization
Lcell: 102/10570(<1%)
DSP Block 9-bit elements: 24/48 (50%)
Memory bits: 0/920448(0%)
Performance
73 MHz
Latency
4 clock cycles
Basic IIR Filter Design Example
Download the 4th Order IIR Filter (iir.zip) design example from the
Design Examples section of the Altera web site at www.altera.com.
Butterworth IIR Filters
Butterworth filters are the most popular version of IIR analog filters.
These filters are also known as “maximally flat” because they have no
passband ripple. Additionally, they have a monotonic response in both
the stopband and the passband. Butterworth filters trade-off roll off
steepness for their no ripple characteristic. The distinguishing
Butterworth filter feature is its poles are arranged in a uniquely
symmetrical manner along a circle in the s-plane. The expression for the
Butterworth filter’s magnitude-squared function is as follows:
H c ( jω)
2
1
= --------------------------jω 2N
⎛
1 + -------⎞
⎝ jωc⎠
where:
ωc is the cut-off frequency
N is the filter order
The filter’s cutoff characteristics become sharper as N increases. If a
substitution is made such that jω = s, then the following equation is
derived:
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Infinite Impulse Response (IIR) Filters
1
H c ( s )H c ( – s ) = ---------------------------s 2N
1 + ⎛ -------⎞
⎝ jωc⎠
with poles at:
sk = ( –1 )
= ωc e
1
------2N
( jωc )
jπ ⎞
⎛ ------( 2k + N – 1 )
⎝ 2N⎠
for k=0,1,…,2N-1
There are 2N poles on the circle with a radius of ωc in the s-plane. These
poles are evenly spaced at π/N intervals along the circle. The poles chosen
for the implementation of the filter lie in the left half of the s-plane,
because these generate a stable, causal filter.
Each of the impulse invariance, the bilinear, and matched z transforms
can transform the Laplace transform of the Butterworth filter into the ztransform.
■
Impulse invariance transforms take the inverse of the Laplace
transform to obtain the impulse response, then perform a
z-transform on the sampled impulse response. The impulse
invariance method can cause some aliasing.
■
The bilinear transform maps the entire jω-axis in the s-plane to one
revolution of the unit circle in the z-plane. This is the most popular
method because it inherently eliminates aliasing.
■
The matched z-transform maps the poles and the zeros of the filter
directly from the s-plane to the z-plane. Usually, these transforms are
transparent to the user because several tools, such as MATLAB, exist
for determining the coefficients of the filter. The z-transform
generates the coefficients much like in the basic IIR filter discussed
earlier.
Butterworth Filter Implementation
For digital designs, consideration must be made to optimize the IIR
biquad structure so that it maps optimally into logic. Because speed is
often a critical requirement, the goal is to reduce the number of
operations per biquad. It is possible to reduce the number of multipliers
needed in each biquad to just two.
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Through the use of integer feedforward multiplies, which can be
implemented by combining addition, shifting, and complimenting
operations, a Butterworth filter’s transfer function biquad can be
optimized for logic synthesis. The most efficient transformation is that of
an all pole filter. This is because there is a unique relationship between the
feedforward integer coefficients of the filter represented as:
–1
–2
1 + 2z + z H ( z ) = -----------------------------------------–1
–2
1 + b1 z + b2 z
As can be seen by this equation, the z-1 coefficient in the numerator
(representing the feedforward path) is twice the other two operands (z-2
and 1). This is always the case in the transformation from the frequency
to the digital domain. This represents the normalized response, which is
faster and smaller to implement in hardware than real multipliers. It
introduces a scaling factor as well, but this can be corrected at the end of
the cascade chain through a single multiply.
Figure 7–24 shows how a Butterworth filter biquad is implemented in a
Stratix or Stratix GX device.
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Infinite Impulse Response (IIR) Filters
Figure 7–24. Butterworth Filter Biquad Notes (1), (2)
w(n-1)
DSP block
b1
D
w(n)
Q
w(n-2)
b2
D
Q
x(n)
w(n)
w(n-1)
y(n)
Notes to Figure 7–24:
(1)
Unused ports are grayed out.
(2)
The z-1 coefficient is a multiple of the other coefficients (z-2 and 1) in the
feedforward path. This is implemented using a shift operation.
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
The DSP block in Figure 7–24 is configured in multiply and add mode.
The three external adders are implemented in logic elements and
therefore are not part of the DSP block. Therefore, for an 18-bit input, each
biquad requires half a DSP block and three logic element adders. The gain
factor can be compensated for at the end of the filtering stage and is not
shown in this simple example. More complex, higher order Butterworth
filters can be realized by cascading several biquads together, as in the IIR
example. Figure 7–25 below shows a 4th order Butterworth filter using
two cascaded biquads in a single DSP block.
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Infinite Impulse Response (IIR) Filters
Figure 7–25. Cascaded Butterworth Biquads Note (1)
D
Q
D
Q
D
Q
w1(n-2)
First
biquad
w1(n-1)
w1(n-1)
DSP
block
b11
D
Q
w1(n)
w1(n-2)
D
Q
b12
D
Q
x(n)
w2(n-1)
D
b21
D
Q
Second
biquad
Q
w2(n)
w2(n-2)
b22
D
D
Q
D
Q
D
Q
Q
w2(n-1)
w2(n-2)
y(n)
Note to Figure 7–25:
(1)
The gain factor is compensated for at the end of the filtering stage and is not shown in this figure.
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September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Butterworth Filter Implementation Results
Table 7–16 shows the results of implementing a 4th order Butterworth
filter as shown in Figure 7–25.
Table 7–16. 4th Order Butterworth Filter Implementation Results
Part
EP1S10F780C6
Utilization
Lcell: 251/10570(2%)
DSP Block 9-bit elements: 16/48 (33%)
Memory bits: 0/920448 (0%)
Performance
80 MHz
Latency
4 clock cycles
Butterworth Filter Design Example
Download the 4th Order Butterworth Filter (butterworth.zip) design
example from the Design Examples section of the Altera web site at
www.altera.com.
Matrix
Manipulation
DSP relies heavily on matrix manipulation. The key idea is to transform
the digital signals into a format that can then be manipulated
mathematically.
This section describes an example of matrix manipulation used in 2-D
convolution filter, and its implementation in a Stratix device.
Background on Matrix Manipulation
A matrix can represent all digital signals. Apart from the convenience of
compact notation, matrix representation also exploits the benefits of
linear algebra. As with one-dimensional, discrete sequences, this
advantage becomes more apparent when processing multi-dimensional
signals.
In image processing, matrix manipulation is important because it
requires analysis in the spatial domain. Smoothing, trend reduction, and
sharpening are examples of common image processing operations, which
are performed by convolution. This can also be viewed as a digital filter
operation with the matrix of filter coefficients forming a convolutional
kernel, or mask.
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Matrix Manipulation
Two-Dimensional Filtering & Video Imaging
FIR filtering for video applications and image processing in general is
used in many applications, including noise removal, image sharpening to
feature extraction.
For noise removal, the goal is to reduce the effects of undesirable,
contaminative signals that have been linearly added to the image.
Applying a low pass filter or smoothing function flattens the image by
reducing the rapid pixel-to-pixel variation in gray levels and, ultimately,
removing noise. It also has a blurring effect usually used as a precursor
for removing unwanted details before extracting certain features from the
image.
Image sharpening focuses on the fine details of the image and enhances
sharp transitions between the pixels. This acts as a high-pass filter that
reduces broad features like the uniform background in an image and
enhances compact features or details that have been blurred.
Feature extraction is a form of image analysis slightly different from
image processing. The goal of image analysis in general is to extract
information based on certain characteristics from the image. This is a
multiple step process that includes edge detection. The easiest form of
edge detection is the derivative filter, using gradient operators.
All of the operations above involve transformation of the input image.
This can be presented as the convolution of the two-dimensional input
image, x(m,n) with the impulse response of the transform, f(k,l), resulting
in y(m,n) which is the output image.
y ( m, n ) = f ( k, l ) ⊗ x ( m, n )
N
y ( m, n ) =
N
∑ ∑ f ( k,
l )x ( m – k, n – l )
k = –N l = –N
The f(k,l) function refers to the matrix of filter coefficients. Because the
matrix operation is analogous to a filter operation, the matrix itself is
considered the impulse response of the filter. Depending on the type of
operation, the choice of the convolutional kernel or mask, f(k,l) is
different. Figure 7–26 shows an example of convolving a 3 × 3 mask with
a larger image.
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Figure 7–26. Convolution Using a 3 × 3 Kernel
The output pixel value, y(m,n) depends on the surrounding pixel values
in the input image, as well as the filter weights:
y ( m, n ) = w 1 x ( m – 1, n – 1 ) + w 2 x ( m – 1, n ) + w 3 x ( m – 1, n + 1 )
+ w 4 x ( m, n – 1 ) + w 5 x ( m, n ) + w 6 x ( m, n + 1 )
+ w 7 x ( m + 1, n – 1 ) + w 8 x ( m + 1, n ) + w 9 x ( m + 1, n + 1 )
To complete the transformation, the kernel slides across the entire image.
For pixels on the edge of the image, the convolution operation does not
have a complete set of input data. To work around this problem, the pixels
on the edge can be left unchanged. In some cases, it is acceptable to have
an output image of reduced size. Alternatively, the matrix effect can be
applied to edge pixels as if they are surrounded on the “empty” side by
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Matrix Manipulation
black pixels, that is pixels with value zero. This is similar to padding the
edges of the input image matrix with zeros and is referred to as the free
boundary condition. This is shown in Figure 7–27.
Figure 7–27. Using Free Boundary Condition for Edge Pixels
3 x 3 kernel slides across image
0
0
0
0
Image boundary
x m , n + 1)
x(
x
x(
Image
0
x m + 1, n )
x(
x m + 1, n + 1)
x(
Image boundary
Convolution Implementation
This design example shows a 3 × 3 2-D FIR filter that takes in an 8 × 8
input image with gray pixel values ranging from 0-255 (8-bit). Data is fed
in serially starting from the top left pixel, moving horizontally on a rowby-row basis. Next the data is stored in three separate RAM blocks in the
buffering stage. Each M512 memory block represents a line of the image,
and this is cycled through. For a 32 × 32 input image, the design needs
M4K memory blocks. For larger images (640 × 480), this can be extended
to M-RAM blocks or other buffering schemes. The control logic block
provides the RAM control signals to interleave the data across all three
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RAM blocks. The 9-bit signed filter coefficients feed directly into the filter
block. As the data is shifted out from the RAM blocks, the multiplexer
block checks for edge pixels and uses the free boundary condition.
Figure 7–28 shows a top-level diagram of the design.
Figure 7–28. Block Diagram on Implementation of 3 × 3 Convolutional Filter for an 8 × 8 Pixel Input Image
The 3 × 3 filter block implements the nine multiply-add operations in
parallel using two DSP blocks. One DSP block can implement eight of
these multipliers. The second DSP block implements the ninth multiplier.
The first DSP block is in the four-multipliers adder mode, and the second
is in simple multiplier mode. In addition to the two DSP blocks, an
external adder is required to sum the output of all nine multipliers.
Figure 7–29 shows this implementation.
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Matrix Manipulation
Figure 7–29. Implementation of 3 × 3 Convolutional Filter Block
DSP Block in Four-Multipliers Adder Mode (9-bit)
w1
x(m - 1, n - 1)
w2
x(m - 1, n )
w3
x(m - 1, n + 1)
w4
x(m , n - 1)
w5
LE implemented
adder
x(m , n )
w6
x(m , n + 1)
y(m , n )
w7
x(m + 1, n - 1)
w8
x(m + 1, n )
DSP Block in Simple Multiplier Mode (8-bit)
w9
x(m + 1, n + 1)
Note: Unused multipliers and
adders grayed out. These
multipliers can be used by other
functions.
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Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
In cases where a symmetric 2-D filter is used, pixels sharing the same
filter coefficients from three separate line-stores A, B, and C can be added
together prior to the multiplication operation. This reduces the number of
multipliers used. Referring to Figure 7–30, w1, w2, and w3 are the filter
coefficients. Figure 7–31 shows the implementation of this circular
symmetric filter.
Figure 7–30. Symmetric 3 × 3 Kernel
Figure 7–31. Details on Implementation of Symmetric 3 × 3 Convolution Filter Block
Logic Elements
DSP Block - Four Multipliers
Adder Mode (9-bit)
A
w1
y(m , n )
w2
B
w3
C
GND
GND
Note: Unused multipliers and adders grayed out. These
multipliers can be used by other functions.
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Discrete Cosine Transform (DCT)
Convolution Implementation Results
Table 7–17 shows the results of the 3 × 3 2-D FIR filter implementation in
Figure 7–28.
Table 7–17. 3 × 3 2-D Convolution Filter Implementation Results
Part
EP1S10F780
Utilization
Lcell: 372/10570 (3%)
DSP block 9-bit elements: 9/48 (18%)
Memory bits: 768/920448 (<1%)
Performance
226 MHz
Latency
15 clock cycles
The design requires the input to be an 8 × 8 image, with 8-bit input data
and 9-bit filter coefficient width. The output is an image of the same size.
Convolution Design Example
Download the 3 × 3 2-D Convolutional Filter (two_d_fir.zip) design
example from the Design Examples section of the Altera web site at
www.altera.com.
Discrete Cosine
Transform (DCT)
The discrete cosine transform (DCT) is widely used in video and audio
compression, for example in JPEG, MPEG video, and MPEG audio. It is a
form of transform coding, which is the preferred method for compression
techniques. Images tend to compact their energy in the frequency domain
making compression in the frequency domain much more effective. This
is an important element in compressing data, where the goal is to have a
high data compression rate without significant degradation in the image
quality.
DCT Background
Similar to the discrete fourier transform (DFT), the DCT is a function that
maps the input signal or image from the spatial to the frequency domain.
It transforms the input into a linear combination of weighted basis
functions. These basis functions are the frequency components of the
input data.
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For 1-D with input data x(n) of size N, the DCT coefficients Y(k) are:
α( k )
Y ( k ) = ----------2
N–1
( 2n + 1 )πk
-⎞
∑ x ( n ) cos ⎛⎝ -------------------------⎠
2N
for 0 ≤ k ≤ N–1
n=0
where:
α( k ) =
1
---N
for k = 0
α( k ) =
2--N
for 1 ≤ k ≤ N –1
For 2-D with input data x(m,n) of size N × N, the DCT coefficients for the
output image, Y(p,q) are:
α( p )α( q )
Y ( p, q ) = ----------------------2
N–1N–1
∑ ∑ x ( m,
( 2m + 1 )πp
( 2n + 1 )πq
n ) cos ⎛ -----------------------------⎞ cos ⎛ ---------------------------⎞
⎝
⎠
⎝
⎠
2N
2N
m = 0n = 0
where:
α( p ) =
1--N
for p = 0
α( q ) =
1
---N
for q = 0
α( p ) =
2--N
for 1 ≤ p ≤ N –1
α( q ) =
2--N
for 1 ≤ q ≤ N–1
2-D DCT Algorithm
The 2-D DCT can be thought of as an extended 1-D DCT applied twice;
once in the x direction and again in the y direction. Because the 2-D DCT
is a separable transform, it is possible to calculate it using efficient 1-D
algorithms. Figure 7–32 illustrates the concept of a separable transform.
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Discrete Cosine Transform (DCT)
Figure 7–32. A 2-D DCT is a Separable Transform
This section uses a standard algorithm proposed in [1]. Figure 7–33
shows the flow graph for the algorithm. This is similar to the butterfly
computation of the fast fourier transform (FFT). Similar to the FFT
algorithms, the DCT algorithm reduces the complexity of the calculation
by decomposing the computation into successively smaller DCT
components. The even coefficients (y0, y2, y4, y6) are calculated in the
upper half and the odd coefficients (y1, y3, y5, y7) in the lower half. As a
result of the decomposition, the output is reordered as well.
Figure 7–33. Implementing an N=8 Fast DCT
Stage 1
Stage 4
Stage 2 Stage 3
y0
x0
x1
C4
y4
x2
C6 -C2
y2
x3
C2 C6
y6
x4
C7 -C C
5 3 -C1
C5 -C C
1 7 C3
C3 -C -C
7 1 -C5
C1 C C
3 5 C7
y1
x5
x6
x7
a
y3
y5
y7
Sum a and b
b
Multiplied by -1
S31
S32
.
.
.
S3n
7–54
Stratix Device Handbook, Volume 2
Cm1
C.m2
.
.
.
Cmn
yk
Multiply-addition block
Stage 3 output (S3)
Matrix coefficent (Cmn)
yk = cm1s31 + cm2s32 + ... + cmns3n
where cx = cos
(16x π)
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
The following defines in matrix format, the 8-point 1-D DCT of
Figure 7–33:
Y 1D = x × Add 1 × Add 2 × Add 3 × C
where:
[x] is the 1 × 8 input matrix
Altera Corporation
September 2004
Add 1 =
1
0
0
0
0
0
0
1
0
1
0
0
0
0
1
0
0
0
1
0
0
1
0
0
0
0
0
1
1
0
0
0
0
0
0
1
–1
0
0
0
0
0
1
0
0
–1
0
0
0
1
0
0
0
0
–1
0
1
0
0
0
0
0
0
–1
Add 2 =
1
0
0
1
0
0
0
0
0
1
1
0
0
0
0
0
0
1
–1
0
0
0
0
0
1
0
0
–1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
Add 3 =
1
1
0
0
0
0
0
0
1
–1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
7–55
Stratix Device Handbook, Volume 2
Discrete Cosine Transform (DCT)
C =
1
0
0
C4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
C6 –C2 0
0
0
0
0
0
C2 C6
0
0
0
0
0
0
0
C7 –C5 C3 –C1
0
0
0
0
C5 –C1 C7 C3
0
0
0
0
C3 –C7 –C1 –C5
0
0
0
0
C1 C3 C5 C7
0
C x = cos πx
-----16
All of the additions in stages 1, 2 and 3 of Figure 7–32 appear in
symmetric add and subtract pairs. The entire first stage is simply four
such pairs in a very typical cross-over pattern. This pattern is repeated in
stages 2 and 3. Multiplication operations are confined to stage 4 in the
algorithm. This implementation is shown in more detail in the next
section.
DCT Implementation
In taking advantage of the separable transform property of the DCT, the
implementation can be divided into separate stages; row processing and
column processing. However, some data restructuring is necessary
before applying the column processing stage to the results from the row
processing stage. The data buffering stage must transpose the data first.
Figure 7–34 shows the different stages.
Figure 7–34. Three Separate Stages in Implementing the 2-D DCT
Row
processing
Transpose
matrix
Column
processing
Because the row processing and column processing blocks share the same
1-D 8-point DCT algorithm, the hardware implementation shows this
block as being shared. The DCT algorithm requires a serial-to-parallel
conversion block at the input because it works on blocks of eight data
7–56
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
points in parallel. There is also a parallel-to-serial conversion block at the
output because the column processing stage generates the output image
column-by-column. In order to have the output in the same order as the
input (i.e., row-by-row), this conversion is necessary. Appropriate scaling
needs to be applied to the completed transform but this can be combined
with the quantization stage which often follows a DCT [1]. Figure 7–35
shows a top-level block diagram of this design.
Figure 7–35. Block Diagram on Serial Implementation of 2-D DCT
The implementation of the 1-D DCT block is based on the algorithm
shown in Figure 7–33. The simple addition and subtraction operations in
stages 1, 2 and 3 are implemented using logic cells. The multiply and
multiply-addition operations in stage 4 are implemented using DSP
blocks in the Stratix device in the simple multiplier mode, two-multiplier
adder mode, and the four-multiplier adder mode. An example of the
multiply-addition block is shown in Figure 7–36.
Altera Corporation
September 2004
7–57
Stratix Device Handbook, Volume 2
Discrete Cosine Transform (DCT)
Figure 7–36. Details on the Implementation of the Multiply-Addition Operation
in Stage 4 of the 1-D DCT Algorithm
DSP Block - Four-Multipliers Adder Mode (18-bit)
S31
Cm1
S32
Cm2
yk
S33
Cm3
S34
Cm4
Note to Figure 7–36:
(1)
Referring to Figure 7–33. S3n is an output from stage 3 of the DCT and Cmn is a
matrix coefficient. Cx = cos (xπ/16).
DCT Implementation Results
Table 7–18 shows the results of implementing a 2-D DCT with 18-bit
precision, as shown in Figure 7–35.
Table 7–18. 2-D DCT Implementation Results
Part
EP1S20F780
Utilization
Lcell: 1717/18460 (9%)
DSP Block 9-bit element: 18/80 (22%)
Memory bits: 2816/1669248 (<1%)
Performance
165 MHz
Latency
80 clock cycles
DCT Design Example
Download the 2-D convolutional filter (d_dct.zip) design example from
the Design Examples section of the Altera web site at www.altera.com.
7–58
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Arithmetic
Functions
Arithmetic functions, such as trigonometric functions, including sine,
cosine, magnitude and phase calculation, are important DSP elements.
This section discusses the implementation of a simple vector magnitude
function in a Stratix device.
Background
Complex numbers can be expressed in two parts: real and imaginary.
z = a + jb
where:
a is the real part
b is the imaginary part
j2= –1
In a two-dimensional plane, a vector (a,b) with reference to the origin
(0,0) can also be represented as a complex number. In essence, the x-axis
represents the real part, and the y-axis represents the imaginary part (see
Figure 7–37).
Figure 7–37. Magnitude of Vector (a,b)
Complex numbers can be converted to phase and amplitude or
magnitude representation, using a Cartesian-to-polar coordinate
conversion. For a vector (a,b), the phase and magnitude representation is
the following:
Altera Corporation
September 2004
7–59
Stratix Device Handbook, Volume 2
Arithmetic Functions
Magnitude m =
2
a +b
2
Phase angle θ = tan-1(b/a)
This conversion is useful in different applications, such as position
control and position monitoring in robotics. It is also important to have
these transformations at very high speeds to accommodate real-time
processing.
Arithmetic Function Implementation
A common approach to implementing these arithmetic functions is using
the coordinate rotation digital computer (CORDIC) algorithm. The
CORDIC algorithm calculates the trigonometric functions of sine, cosine,
magnitude, and phase using an iterative process. It is made up of a series
of micro-rotations of the vector by a set of predetermined constants,
which are powers of 2.
Using binary arithmetic, this algorithm essentially replaces multipliers
with shift and add operations. In Stratix devices, it is possible to calculate
some of these arithmetic functions directly, without having to implement
the CORDIC algorithm.
This section describes a design example that calculates the magnitude of
a 9-bit signed vector (a,b) using a pipelined version of the square root
function available at the Altera IP Megastore. To calculate the sum of the
squares of the input (a2 + b2), configure the DSP block in the twomultipliers adder mode. The square root function is implemented using
an iterative algorithm similar to the long division operation. The binary
numbers are paired off, and subtracted by a trial number. Depending on
if the remainder is positive or negative, each bit of the square root is
determined and the process is repeated. This square root function does
not require memory and is implemented in logic cells only.
In this example, the input bit precision (IN_PREC) feeding into the square
root macro is set to twenty, and the output precision (OUT_PREC) is set to
ten. The number of precision bits is parameterizable. Also, there is a third
parameter, PIPELINE, which controls the architecture of the square root
macro. If this parameter is set to YES, it includes pipeline stages in the
square root macro. If set to NO, the square root macro becomes a singlecycled combinatorial function.
Figure 7–38 shows the implementation the magnitude design.
7–60
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
Figure 7–38. Implementing the Vector Magnitude Function
DSP Block - Two Multipliers
Adder Mode (9-bit)
LE implemented
square root function
a
b
Note: Unused multipliers
and adders grayed out.
Altera Corporation
September 2004
7–61
Stratix Device Handbook, Volume 2
Conclusion
Arithmetic Function Implementation Results
Table 7–19 shows the results of the implementation shown in Figure 7–38
with the PIPELINE parameter set to YES. Table 7–20 shows the results of
the implementation shown in Figure 7–38 with the PIPELINE parameter
set to NO.
Table 7–19. Vector Magnitude Function Implementation Results
(PIPELINE=YES)
Part
EP1S10F780
Utilization
Lcell: 497/10570 (4%)
DSP block 9-bit elements: 2/48 (4%)
Memory bits: 0/920448 (0%)
Performance
194 MHz
Latency
15 clock cycles
Table 7–20. Vector Magnitude Function Implementation Results
(PIPELINE=NO)
Part
EP1S10F780
Utilization
Lcell: 244/10570 (2%)
DSP block 9-bit elements: 2/48 (4%)
Memory bits: 0/920448 (0%)
Performance
30 MHz
Latency
3 clock cycles
Arithmetic Function Design Example
Download the Vector Magnitude Function (magnitude.zip) design
example from the Design Examples section of the Altera web site at
www.altera.com.
Conclusion
The DSP blocks in Stratix and Stratix GX devices are optimized to support
DSP functions requiring high data throughput, such as FIR filters, IIR
filters and the DCT. The DSP blocks are flexible and configurable in
different operation modes based on the application’s needs. The
TriMatrix memory provides the data storage capability often needed in
DSP applications.
The DSP blocks and TriMatrix memory in Stratix and Stratix GX devices
offer performance and flexibility that translates to higher performance
DSP functions.
7–62
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Implementing High Performance DSP Functions in Stratix & Stratix GX Devices
References
Altera Corporation
September 2004
See the following for more information:
■
Optimal DCT for Hardware Implementation
M. Langhammer. Proceedings of International Conference on Signal
Processing Applications & Technology (ICSPAT) '95, October 1995
■
Digital Signal Processing: Principles, Algorithms, and Applications
John G. Proakis, Dimitris G. Manolakis. Prentice Hall
■
Hardware Implementation of Multirate Digital Filters
Tony San. Communication Systems Design, April 2000
■
AN 73: Implementing FIR Filters in FLEX Devices
■
Efficient Logic Synthesis Techniques for IIR Filters
M.Langhammer. Proceedings of International Conference on Signal
Processing Applications & Technology (ICSPAT) '95, October 1995
7–63
Stratix Device Handbook, Volume 2
References
7–64
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Section V. IP & Design
Considerations
This section provides documentation on some of the IP functions offered
by Altera® for Stratix® devices. (Also see the Intellectual Property section
of the Altera web site for a complete offering of IP cores for Stratix
devices.) The last chapter details design considerations for migrating
from the APEX™ architecture.
This section contains the following chapters:
Revision History
Chapter
8
■
Chapter 8, Implementing 10-Gigabit Ethernet Using Stratix &
Stratix GX Devices
■
Chapter 9, Implementing SFI-4 in Stratix & Stratix GX Devices
■
Chapter 10, Transitioning APEX Designs to Stratix & Stratix GX
Devices
The table below shows the revision history for Chapters 8 through 10.
Date/Version
July 2005, v2.0
Updated Stratix GX device information.
●
Table 8–2 on page 8–10: updated table, deleted Note 1, and updated
Note 2.
Updated Table 8–4 on page 8–12.
November 2003, v1.1
●
Removed support for series and parallel on-chip termination.
April 2003, v1.0
●
No new changes in Stratix Device Handbook v2.0.
July 2005, v2.0
●
Updated Stratix GX device information.
September 2004, v1.1
●
●
Table 9–2 on page 9–9: updated table, deleted Note 1, and updated
Note 2.
Updated Table 9–4 on page 9–10.
●
No new changes in Stratix Device Handbook v2.0.
September 2004, v1.2
9
Changes Made
April 2003, v1.0
Altera Corporation
●
Section V–1
IP & Design Considerations
Stratix Device Handbook, Volume 2
Chapter
Date/Version
10
July 2005, v3.0
●
Updated Stratix GX device information.
September 2004, v2.1
●
Updated Table 10–9 on page 10–26.
April 2004, v2.0
●
●
Synchronous occurrences renamed pipelined.
Asynchronous occurrences renamed flow-through.
November 2003, v1.2
●
Removed support for series and parallel on-chip termination.
October 2003, v1.1
●
Updated Table 10–6.
April 2003, v1.0
●
No new changes in Stratix Device Handbook v2.0.
Section V–2
Changes Made
Altera Corporation
8. Implementing 10-Gigabit
Ethernet Using Stratix &
Stratix GX Devices
S52010-2.0
Introduction
Ethernet has evolved to meet ever-increasing bandwidth demands and is
the most prevalent local-area network (LAN) communications protocol.
10-Gigabit Ethernet extends that protocol to higher bandwidth for future
high-speed applications. The accelerated growth of network traffic and
the resulting increase in bandwidth requirements is driving service
providers and enterprise network architects towards high-speed network
solutions. Potential applications for 10-Gigabit Ethernet include private
campus or LAN backbones, high-speed access links between service
providers and enterprises, and aggregation and transport in metropolitan
area networks (MANs).
The I/O features of Stratix® and Stratix GX devices enable support for 10Gigabit Ethernet, supporting 10-Gigabit 16-bit interface (XSBI) and 10Gigabit medium independent interface (XGMII). Stratix GX devices can
additionally support the 10-gigabit attachment unit interface (XAUI)
using the embedded 3.125-Gbps transceivers. You can find more
information on XAUI support in Section II, Stratix GX Transceiver User
Guide, of the Stratix GX Device Handbook, Volume 1.
This chapter discusses the following topics:
■
■
■
■
■
Fundamentals of 10-Gigabit Ethernet
Description and implementation of XSBI
Description and implementation of XGMII
Description of XAUI
I/O characteristics of XSBI, XGMII, and XAUI
Related Links
■
■
■
10-Gigabit
Ethernet
Altera Corporation
July 2005
10-Gigabit Ethernet Alliance at www.10gea.org
The Stratix Device Family Data Sheet section of the Stratix Device
Handbook, Volume 1 and the Stratix GX Device Family Data Sheet
section of the Stratix GX Device Handbook, Volume 1
The High-Speed Differential I/O Interfaces in Stratix Devices chapter
Ethernet speed has increased to keep pace with demand, initially to
10 megabits per second (Mbps), later to 100 Mbps, and recently to
1 gigabit per second (Gbps). Ethernet is the dominant network
technology in LANs, and with the advent of 10-Gigabit Ethernet, it is
entering the MAN and wide area network (WAN) markets.
8–1
10-Gigabit Ethernet
The purpose of the 10-Gigabit Ethernet proposed standard is to extend
the operating speed to 10 Gbps defined by protocol IEEE 802.3 and
include WAN applications. These additions provide a significant increase
in bandwidth while maintaining maximum compatibility with current
IEEE 802.3 interfaces.
Since its inception in March 1999, the 10-Gigabit Ethernet Task Force has
been working on the IEEE 802.3ae Standard. Some of the information in
the following sections is derived from Clauses 46, 47, 49, and 51 of the
IEEE Draft P802.3ae/D3.1 document. A fully ratified standard is
expected in the first half of 2002. Figure 8–1 shows the relationship of
10-Gigabit Ethernet to the Open Systems Interconnection (OSI) protocol
stack.
Figure 8–1. 10-Gigabit Ethernet Protocol in Relation to OSI Protocol Stack
Higher Layers
OSI Reference
Model Layers
LLC (1)
MAC (2)
Application
Reconciliation
Presentation
XGMII
Session
Transport
PCS (3)
XSBI
PHY (4)
PMA (5)
Network
PMD (6)
Data Link
MDI (7)
Physical
Medium
Notes to Figure 8–1:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
LLC: logical link controller
MAC: media access controller
PCS: physical coding sublayer
PHY: physical layer
PMA: physical medium attachment
PMD: physical medium dependent
MDI: medium dependent interface
8–2
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
The Ethernet PHY (layer 1 of the OSI model) connects the media (optical
or copper) to the MAC (layer 2). The Ethernet architecture further divides
the PHY (layer 1) into a PMD sublayer, a PMA sublayer, and a PCS. For
example, optical transceivers are PMD sublayers. The PMA converts the
data between the PMD sublayer and the PCS sublayer. The PCS is made
up of coding (e.g., 8b/10b, 64b/66b) and serializer or multiplexing
functions. Figure 8–2 shows the components of 10-Gigabit Ethernet and
how Altera implements certain blocks and interfaces.
10-Gigabit Ethernet has three different implementations for the PHY:
10GBASE-X, 10GBASE-R, and 10GBASE-W. The 10GBASE-X
implementation is a PHY that supports the XAUI interface. The XAUI
interface used in conjunction with the XGMII extender sublayer (XGXS)
allows more separation in distance between the MAC and PHY.
10GBASE-X PCS uses four lanes of 8b/10b coded data at a rate of
3.125 Gbps. 10GBASE-X is a wide wave division multiplexing (WWDM)
LAN PHY. 10GBASE-R and 10GBASE-W are serial LAN PHYs and serial
WAN PHYs, respectively. Unlike 10GBASE-X, 10GBASE-R and
10GBASE-W implementations have a XSBI interface and are described in
more detail in the following section.
Altera Corporation
July 2005
8–3
Stratix Device Handbook, Volume 2
10-Gigabit Ethernet
Figure 8–2. 10-Gigabit Ethernet Block Diagram
Interface directly covered in this
application note
MAC
Interface indirectly covered in this
application note
RS (1)
Can be implemented in Altera PLDs
XGMII (32 Bits at 156.25 Mbps DDR 1.5-V HSTL)
8b/10b
XGXS (2)
XAUI (4 Bits at 3.125 Gbps PCML)
XGXS
8b/10b
XGMII (32 Bits at 156.25 Mbps DDR 1.5-V HSTL)
PCS
8B/10B
PCS
64b/66b
PCS
64b/66b
WIS (3)
PHY
PMA
XSBI (16 Bits at
644.5 Mbps LVDS)
PMA
PMD
PMD
MDI
10GBASE-X
XSBI (16 Bits at
622.08 Mbps LVDS)
PMA
PMD
OC-192 Framing
MDI
10GBASE-R
10GBASE-W
Notes to Figure 8–2:
(1)
(2)
(3)
The reconciliation sublayer (RS) interfaces the serial MAC data stream and the parallel data of XGMII.
The XGMII extender sublayer (XGXS) extends the distance of XGMII when used with XUAI and provides the data
conversion between XGMII and XAUI.
The WAN interface sublayer (WIS) implements the OC-192 framing and scrambling functions.
8–4
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Interfaces
The following sections discuss XSBI, PCS, XGMII, and XAUI.
XSBI
One of the blocks of 10-Gigabit Ethernet is the XSBI interface. XSBI is the
interface between the PCS and the PMA sublayers of the PHY layer of the
OSI model. XSBI supports two types of PHY layers, LAN PHY and WAN
PHY. The LAN PHY is part of 10GBASE-R, and supports existing
Gigabit Ethernet applications at ten times the bandwidth. The WAN PHY
is part of 10GBASE-W, and supports connections to existing and future
installations of SONET/SDH circuit-switched access equipment.
10GBASE-R is a physical layer implementation that is comprised of the
PCS sublayer, the PMA, and the PMD. 10GBASE-R is based upon
64b/66b data coding. 10GBASE-W is a PHY layer implementation that is
comprised of the PCS sublayer, the WAN interface sublayer (WIS), the
PMA, and the PMD. 10GBASE-W is based on STS-192c/SDH VC-4-64c
encapsulation of 64b/66b encoded data. Figure 8–3 shows the
construction of these two PHY layers.
Figure 8–3. XSBI Interface for the Two PHY Layers
PCS
PCS
WIS
XSBI
PHY
PMA
PMA
PMD
PMD
MDI
Altera Corporation
July 2005
Medium
Medium
10GBASE-R
10GBASE-W
8–5
Stratix Device Handbook, Volume 2
Interfaces
Functional Description
XSBI uses 16-bit LVDS data to interface between the PCS and the PMA
sublayer. Figure 8–4 shows XSBI between these two sublayers.
Figure 8–4. XSBI Functional Block Diagram
REFCLK
Transmitter
TX_D[15..0]
Transmitter
PMA_TXCLK
PCS
PMA
PMA_TXCLK_SRC
Receiver
Receiver
RX_D[15..0]
PCS
PMA_RXCLK
PMA
Sync_Err (optional)
On the transmitter side, the transmit data (TX_D[15..0]) is output by
the PCS and input at the PMA using the transmitter clock (PMA_TXCLK),
which is derived from the PMA source clock (PMA_TXCLK_SRC). The
PMA source clock is generated from the PMA with its reference clock
(REFCLK). On the receiver side, the receiver data (RX_D[15..0]) is
output by the PMA and input at the PCS using the PMA-generated
receiver clock (PMA_RXCLK). The SYNC_ERR optional signal is sent to the
PCS by the PMA if the PMA fails to recover the clock from the serial data
stream.
The ratios for these two clocks and data are dependent on the type of PHY
used. Table 8–1 shows the rates for both PHY types.
Table 8–1. XSBI Clock & Data Rates for WAN & LAN PHY
Parameter
WAN PHY
LAN PHY
Unit
TX_D[15..0]
622.08
644.53125
Mbps
PMA_TXCLK
622.08
644.53125
MHz
PMA_TXCLK_SRC
622.08
644.53125
MHz
RX_D[15..0]
622.08
644.53125
Mbps
PMA_RXCLK
622.08
644.53125
MHz
8–6
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Implementation
The 16-bit full duplex LVDS implementation of XSBI in Stratix devices is
shown in Figure 8–5.
The source-synchronous I/O implemented in Stratix GX devices
optionally includes dynamic phase alignment (DPA). DPA automatically
and continuously tracks fluctuations caused by system variations and
self-adjusts to eliminate the phase skew between the multiplied clock and
the serial data, allowing for data rates of 1 Gbps. In non DPA mode the
I/O behaves similarly to that of the Stratix I/O. This document assumes
that DPA is disabled. However, it is simple to implement the same system
with DPA enabled to take advantage of its features. For more information
on DPA, see the Stratix GX Transceivers chapter in the Stratix GX Device
Handbook, Volume 1.
Figure 8–5. Stratix & Stratix GX Device XSBI Implementation
PMA
Data
TX_D[15..0]
Transmitter
SERDES
PMA_TXCLK
Stratix & Stratix GX PCS
PLL1
Stratix &
Stratix GX
Logic Array
×1
PMA_TXCLK_SRC
÷8
Transmitter
Transmitter
Receiver
PLL2
Phase Shift
÷8
180˚
Receiver
SERDES
PMA_RXCLK
RX_D[15..0]
Data
Receiver
Altera Corporation
July 2005
8–7
Stratix Device Handbook, Volume 2
Interfaces
The transmit serializer/deserializer (SERDES) clock comes from the
transmitter clock source (PMA_TXCLK_SRC). The receiver SERDES clock
comes from the PMA receiver recovered clock (PMA_RXCLK).
Figure 8–6 shows the transmitter output of the XSBI core. Data
transmitted from the PCS to the PMA starts at the core of the Stratix or
Stratix GX device and travels to the Stratix or Stratix GX transmitter
SERDES block. The transmitter SERDES block converts the parallel data
to serial data for 16 individual channels (TX_D[15..0]). The PMA
source clock (PMA_TXCLK_SRC) is used to clock out the signal data.
PMA_TXCLK is generated from the same phase-locked loop (PLL) as the
data, and it travels to the PMA at the same rate as the data. By using one
of the data channels in the middle of the bus as the clock (in this case, the
eighth channel CH8), the clock-to-data skew improves.
Figure 8–6. Stratix & Stratix GX Device XSBI Transmitter Implementation
Stratix & Stratix GX
PCS Transmitter
Stratix & Stratix GX SERDES
Parallel
Register
4 or 8
Parallel-to-Serial
Register
CH0
TX_D[0]
622 Mbps
Stratix & Stratix GX
Logic Array
4 or 8
÷J
Fast PLL
×W
622 MHz
CH7
TX_D[7]
CH8
PMA_TXCLK
CH9
TX_D[8]
CH16
TX_D[15]
PMA
Transmitter
W=1
J = 4 or 8
PMA_TXCLK_SRC
622 MHz
Figure 8–7 shows the receiver input of the XSBI core. From the receiver
side, data (RX_D[15..0]) comes from the PMA to the Stratix or
Stratix GX receiver SERDES block along with the PMA receiver clock
(PMA_RXCLK). The PMA receiver clock is used to convert the serial data
to parallel data. The phase shift or inversion on the PMA receiver clock is
needed to capture the receiver data.
8–8
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Stratix and Stratix GX devices contain up to eight fast PLLs. These PLLs
provide high-speed outputs for high-speed differential I/O support as
well as general- purpose clocking with multiplication and phase shifting.
The fast PLL incorporates this 180° phase shift. The Stratix and Stratix GX
device’s data realignment feature enables you to save more logic
elements (LEs). This feature provides a byte-alignment capability, which
is embedded inside the SERDES. The data realignment circuitry can
correct for bit misalignments by slipping data bits.
f
For more information about fast PLLs, see the Stratix Device Family Data
Sheet section of the Stratix Device Handbook, Volume 1 or the Stratix GX
Device Family Data Sheet section of the Stratix GX Device Handbook,
Volume 1.
Figure 8–7. Stratix & Stratix GX Device XSBI Receiver Implementation
Stratix & Stratix GX PCS Receiver
Stratix & Stratix GX SERDES
Parallel
Register
4 or 8
Parallel-to-Serial
Register
CH0
RX_D[0]
622 Mbps
Stratix & Stratix GX
Logic Array
PMA
Receiver
4 or 8
CH15
÷J
Fast PLL
×W
622 MHz
RX_D[15]
W=1
J = 4 or 8
PMA_RXCLK_SRC
622 MHz
Altera Corporation
July 2005
8–9
Stratix Device Handbook, Volume 2
Interfaces
With this XSBI transmitter and receiver block implementation, each XSBI
core requires two fast PLLs. The potential number of XSBI cores per
device corresponds to the number of fast PLLs each Stratix or Stratix GX
device contains. Tables 8–2 and 8–3 show the number of LVDS channels,
the number of fast PLLs, and the number of XSBI cores that can be
supported for each Stratix or Stratix GX device.
Table 8–2. Stratix Device XSBI Core Support
Stratix Device
Number of LVDS
Channels
Number of Fast
(Receive/Transmit)
PLLs
(1)
Number of XSBI
Interfaces
(Maximum)
EP1S10
44/44
4
2
EP1S20
66/66
4
2
EP1S25
78/78
4
2
EP1S30
82/82
8
4
EP1S40
90/90
8
4
EP1S60
116/116
8
4
EP1S80
152/156
8
4
Note to Table 8–2:
(1)
The LVDS channels can go up to 840 Mbps for flip-chip packages and up to
624 Mbps for wire-bond packages. This number includes both high speed and
low speed channels. The high speed LVDS channels can go up to 840 Mbps. The
low speed LVDS channels can go up to 462 Mbps. The High-Speed Differential I/O
Support chapter in the Stratix Device Handbook, Volume 1, and the device pin-outs
on the web (www.altera.com) specify which channels are high and low speed.
8–10
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Table 8–3. Stratix GX Device XSBI Core Support
Number of LVDS
Channels
Number of Fast
(Receive/Transmit)
PLLs
(1)
Stratix GX Device
Number of XSBI
Interfaces
(Maximum)
EP1SGX10
22/22
2
1
EP1SGX25
39/39
2
2
EP1SGX40
45/45
4
2
Note to Table 8–3:
(1)
The LVDS channels can go up to 840 Mbps for flip-chip packages and up to
624 Mbps for wire-bond packages. This number includes both high speed and
low speed channels. The high speed LVDS channels can go up to 840 Mbps. The
low speed LVDS channels can go up to 462 Mbps. The High-Speed Differential I/O
Support chapter in the Stratix Device Handbook, Volume 1, and the device pin-outs
on the web (www.altera.com) specify which channels are high and low speed.
AC Timing Specifications
Stratix and Stratix GX devices support a PCS interface. Figures 8–8 and
8–9 and Tables 8–4 and 8–5 illustrate timing characteristics of the PCS
transmitter and receiver interfaces.
Figure 8–8 shows the AC timing diagram for the Stratix and Stratix GX
PCS transmitter. You can determine PCS channel-to-channel skew by
adding the data invalid window before the rising edge (Tcq_pre) to the data
invalid window after the rising edge (Tcq_post).
Figure 8–8. PCS Transmitter Timing Diagram
Tperiod
PMA_TX_CLK
TX_DATA[15..0]
Tcq_pre
Altera Corporation
July 2005
Valid
Data
Tcq_post
Tsetup
Thold
8–11
Stratix Device Handbook, Volume 2
Interfaces
Table 8–4 lists the AC timing specifications for the PCS transmitter.
Table 8–4. PCS Transmitter Timing Specifications
Value
Parameter
Unit
Min
Typ
Max
PMA_TX_CLK Tperiod (WAN)
1,608
ps
PMA_TX_CLK Tperiod (LAN)
1,552
ps
Data invalid window before the rising edge
(Tcq_pre)
200
ps
Data invalid window after the rising edge (Tcq_post)
200
ps
40
PMA_TX_CLK duty cycle
PCS transmitter channel-to-channel skew
60
%
200
ps
Figure 8–9 shows the AC timing diagram for the Stratix and Stratix GX
PCS receiver interface. You can determine the PCS sampling window by
adding Tsetup to Thold. Receiver skew margin (RSKM) refers to the amount
of skew tolerated on the printed circuit board (PCB).
Figure 8–9. PCS Receiver Timing Diagram
Tperiod
Tperiod
PMA_RX_CLK
RX_DATA[15..0]
Tcq_pre
PMA_RX_CLK
Valid
Data
RX_DATA[15..0]
Tcq_post
Tsetup
Thold
RSKM
Transmitter Channel-to-Channel
Skew/2
RSKM
Sampling Window
Transmitter Channel-to-Channel
Skew/2
Table 8–5 lists the AC timing specifications for the PCS receiver interface.
Table 8–5. PCS Receiver Timing Specifications (Part 1 of 2)
Value
Parameter
Unit
Min
Typ
Max
PMA_RX_CLK Tperiod (WAN)
1,608
ps
PMA_RX_CLK Tperiod (LAN)
1,552
ps
Data invalid window before the rising edge (Tcq_pre)
200
ps
Data invalid window after the rising edge (Tcq_post)
200
ps
8–12
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Table 8–5. PCS Receiver Timing Specifications (Part 2 of 2)
Value
Parameter
Unit
Min
Typ
Max
PMA_RX_CLK duty cycle
45
Data set-up time (Tsetup)
300
55
ps
%
Data hold time (Thold)
300
ps
PCS sampling window
600
ps
RSKM (WAN)
304
ps
RSKM (LAN)
276
ps
XGMII
The purpose of XGMII is to provide a simple, inexpensive, and easy to
implement interconnection between the MAC sublayer and the PHY.
Though XGMII is an optional interface, it is used extensively in the
10-Gigabit Ethernet standard as the basis for the specification. The
conversion between the parallel data paths of XGMII and the serial MAC
data stream is carried out by the reconciliation sublayer. The
reconciliation sublayer maps the signal set provided at the XGMII to the
physical layer signaling (PLS) service primitives provided at the MAC.
XGMII supports a 10-Gbps MAC data rate.
Functional Description
The XGMII is composed of independent transmit and receive paths. Each
direction uses 32 data signals, TXD[31..0] and RXD[31..0], 4 control
signals, TXC[3..0] and RXC[3..0], and a clock TX_CLK and RX_CLK.
Figure 8–10 shows the XGMII functional block diagram.
Altera Corporation
July 2005
8–13
Stratix Device Handbook, Volume 2
Interfaces
Figure 8–10. XGMII Functional Block Diagram
TXC[3..0]
XGMII
TXD[31..0]
TX_CLK
RXC[3..0]
RXD[31..0]
RX_CLK
PCS
PCS
Transmit
tx_data[15..0]
PCS
Receive
XSBI
rx_data[15..0]
PMA
The 32 TXD and four TXC signals as well as the 32 RXD and four RXC
signals are organized into four data lanes. The four lanes in each direction
share a common clock (TX_CLK for transmit and RX_CLK for receive). The
four lanes are used in round-robin sequence to carry an octet stream
(8 bits of data per lane). The reconciliation sublayer generates continuous
data or control characters on the transmit path and expects continuous
data or control characters on the receive path.
Implementation
XGMII uses the 1.5-V HSTL I/O standard. Stratix and Stratix GX devices
support the 1.5-V HSTL Class I and Class II I/O standard (EIA/JESD8-6).
The standard requires a differential input with an external reference
voltage (VREF) of 0.75 V, as well as a termination voltage VTT of 0.75 V, to
which termination resistors are connected. The HSTL Class I standard
requires a 1.5-V VCCIO voltage, which is supported by Stratix and
Stratix GX devices.
Figure 8–11 shows the 32-bit full-duplex 1.5-V HSTL implementation of
XGMII.
8–14
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Figure 8–11. Stratix & Stratix GX XGMII Implementation
Stratix & Stratix GX PCS
DDR Output Circuitry
MAC (RS)
RX_D[31..0]
Data
Shift
Register
RX_C[3..0]
Clk
MAC_RXCLK
PLL1
Stratix &
Stratix GX
Logic Array
×4
Receiver
Transmitter
Receiver
PLL2
÷4
MAC_TXCLK
TX_D[31..0]
Clk
Shift
Register
Data
DDR Input Circuitry
TX_C[3..0]
Transmitter
For this implementation, the shift register clocks can either be generated
from a divided down MAC reconciliation sublayer transmitter clock
(MAC_TXCLK), or the asynchronous core clock, or both if using a FIFO
buffer.
Figure 8–12 shows one channel of the output half of XGMII. Data that is
transmitted from the PCS to the MAC reconciliation sublayer starts at the
core of the Stratix or Stratix GX device and travels to the shift register. The
shift register takes in the parallel data (even bits sent to the top register
and odd bits sent to the bottom register) and serializes the data. After the
data is serialized, it travels to the double data rate (DDR) output circuitry,
which is clocked with the × 4 clock from the PLL. Out of the DDR output
circuitry, the data drives off-chip along with the × 4 clock. This transaction
creates the DDR relationship between the clock and the data output. This
implementation only shows one channel, but can be duplicated to include
all 32 bits of the RX_D signal and all 4 bits of the RX_C signal.
Altera Corporation
July 2005
8–15
Stratix Device Handbook, Volume 2
Interfaces
Figure 8–12. Stratix & Stratix GX XGMII Output Implementation (One Channel)
Stratix & Stratix GX PCS Output
DDR Output Circuitry
D0,D2,D4,D6
4
Shift
Register
8
DFF
RX_D[0]
DATA
DATA
312.5 Mbps
Stratix &
Stratix GX
Logic Array
4
Shift
Register
D1,D3,D5,D7
DFF
MAC
Receiver
39.0625 MHz
CLK
PLL
×4
156.25 MHz
MAC_RXCLK
CLK
156.25 MHz
Figure 8–13 shows one channel of the input half of the XGMII interface.
From the receiver side, the DDR data is captured from the MAC to the
Stratix and Stratix GX PCS DDR input circuitry. The serial data is
separated into two individual data streams with the even bits routed to
the top register and odd bits routed to the bottom register. The DDR input
circuitry produces two output data streams that go into the shift registers.
From the shift registers, the data is deserialized using the clock from the
MAC, combining into an 8-bit word. This parallel data goes to a register
that is clocked by the divide-by-4 clock from the PLL. This data and clock
go to the Stratix and Stratix GX core. This implementation shows only one
channel, but can be duplicated to include all 32 bits of the TX_D signal and
all 4 bits of the TX_C signal.
8–16
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Figure 8–13. Stratix & Stratix GX XGMII Input Implementation (One Channel)
Stratix & Stratix GX PCS Input
DDR Input Circuitry
D0,D2,D4,D6
TX_D[0]
DATA
4
DFF
312.5 Mbps
Shift
Register
8
DFF
D1,D3,D5,D7
DFF
8
DATA
4
Latch
MAC
Transmitter
Shift
Register
Stratix &
Stratix GX
Logic Array
156.25 MHz
MAC_TXCLK
CLK
156.25 MHz
PLL
÷4
39.0625 MHz
CLK
Stratix and Stratix GX devices contain up to four enhanced PLLs. These
PLLs provide features such as clock switchover, spread-spectrum
clocking, programmable bandwidth, phase and delay control, and PLL
reconfiguration. Since the maximum clock rate is 156.25 MHz, you can
use a fast or enhanced PLL for both the XGMII output and input blocks.
f
For more information about fast PLLs, see the Stratix Device Family Data
Sheet section of the Stratix Device Handbook, Volume 1 or the Stratix GX
Device Family Data Sheet section of the Stratix GX Device Handbook,
Volume 1.
With this implementation for the XGMII output and input blocks, the
number of XGMII cores per device corresponds to the number of PLLs
each Stratix and Stratix GX device contains. Tables 8–6 and 8–7 show the
number of 1.5-V HSTL I/O pins, PLLs, and XGMII cores that are
supported in each Stratix and Stratix GX device. Each core requires 72 1.5-
Altera Corporation
July 2005
8–17
Stratix Device Handbook, Volume 2
Interfaces
V HSTL I/O pins for data and control and 2 clock pins for the transmitter
and receiver clocks. Each XGMII core also needs two PLLs (one for each
direction).
Table 8–6. Stratix XGMII Core Support
Number of 1.5-V
HSTL Class I I/O
Pins
Number of Fast
& Enhanced
PLLs
Number of XGMII
Interfaces
EP1S10
410
6
3
EP1S20
570
6
3
Stratix Device
EP1S25
690
6
3
EP1S30
718
10
5
EP1S40
814
12
6
EP1S60
1,014
12
6
EP1S80
1,195
12
6
Number of 1.5-V
HSTL Class I I/O
Pins
Number of Fast
& Enhanced
PLLs
Number of XGMII
Interfaces
226
4
2
Table 8–7. Stratix GX XGMII Core Support
Stratix Device
EP1SGX10 C, D
EP1SGX25 C
253
4
2
EP1SGX25 D, F
370
4
2
EP1SGX40 D, G
430
8
4
Reduced System Noise
The output buffer of each Stratix and Stratix GX device I/O pin has a
programmable drive strength control for certain I/O standards. The 1.5V HSTL Class I standard supports the minimum setting, which is the
lowest drive strength that guarantees IOH and IOL of the standard. Using
minimum settings provides signal slew rate control to reduce system
noise and signal overshoot.
f
For more information on IOH and IOL values, see Operating Conditions in
the DC & Switching Characteristics chapter of the Stratix Device Handbook,
Volume 1 or Operating Conditions in the DC & Switching Characteristics
chapter of the Stratix GX Device Handbook, Volume 1.
8–18
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Timing
XGMII signals must meet the timing requirements shown in Figure 8–14.
Make all XGMII timing measurements at the driver output (shown in
Figure 8–14) and a capacitive load from all sources of 20 pF that are
specified relative to the VIL_AC(max) and VIH_AC(min) thresholds.
Figure 8–14. XGMII Timing Diagram
TX_CLK
VIH_AC(min)
RX_CLK
VIL_AC(max)
VIH_AC(min)
TXC, TXD,
RXC, RXD
VIL_AC(max)
tsetup
tsetup
thold
thold
Table 8–8 shows the XGMII timing specifications.
Table 8–8. XGMII Timing Specifications Note (1)
Symbol
Driver
Receiver
Unit
Tsetup
960
480
ps
Thold
960
480
ps
Note to Table 8–8:
(1)
The actual set-up and hold times will be made available after device
characterization is complete.
Stratix and Stratix GX devices support DDR data with clock rates of up to
200 MHz, well above the XGMII clock rate of 156.25 MHz. For the HSTL
Class I I/O standard, Stratix and Stratix GX device I/O drivers provide a
1.0-V/ns slew rate at the input buffer of the receiving device.
XAUI
XAUI (pronounced Zowie) is located between the XGMII at the
reconciliation sublayer and the XGMII at the PHY layer. Figure 8–15
shows the location of XAUI. XAUI is designed to either extend or replace
XGMII in chip-to-chip applications of most Ethernet MAC to PHY
interconnects.
Altera Corporation
July 2005
8–19
Stratix Device Handbook, Volume 2
Interfaces
Figure 8–15. XAUI Location
MAC
Reconciliation
XGMII
XGMII Extender
Sublayer (XGXS)
XAUI
XGXS
XGMII
PHY
Functional Description
XAUI can replace the 32 bits of parallel data required by XGMII for
transmission with just 4 lanes of serial data. XAUI uses clock data
recovery (CDR) to eliminate the need for separate clock signals. 8b/10b
encoding is employed on the data stream to embed the clock in the data.
The 8b/10b protocol to encode an 8-bit word stream to 10-bit codes that
results in a DC-balanced serial stream and eases the receiver
synchronization. To support 10-Gigabit Ethernet, each lane must run at a
speed of at least 2.5 Gbps. Using 8b/10b encoding increases the rate for
each lane to 3.125 Gbps, which will be supported in Stratix GX Gbps
devices. This circuitry is supported by the embedded 3.125 Gbps
transceivers within the Stratix GX architecture. You can find more
8–20
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
information on XAUI support in Section II, Stratix GX Transceiver User
Guide of the Stratix GX Device Handbook, Volume 2. Figure 8–16 shows how
XAUI is implemented.
Figure 8–16. Stratix GX XAUI Implementation
Stratix GX XAUI
PCS
8
CDR Tx
Stratix GX
Logic Array
8
CDR Tx
CH0
TX_D[0]
CH3
TX_D[3]
Transmitter
8
CDR Rx
8
CDR Rx
CH0
CH3
RX_D[0]
RX_D[3]
3.125 Gbps
Receiver
I/O
Characteristics
for XSBI, XGMII
& XAUI
The three interfaces of 10-Gigabit Ethernet (XSBI, XGMII, and XAUI) each
have different rates and I/O standards. Table 8–9 shows the
characteristics for each interface.
Table 8–9. 10-Gigabit Ethernet Interfaces Characteristics
Interface
Altera Corporation
July 2005
Width
Clock Rate
(MHz)
Data Rate
Per Channel
Clocking
Scheme
I/O Type
XGMII
32
156.25
312.5 Mbps
DDR source 1.5-V
synchronous HSTL
XSBI
16
644.5 or
622.08
644.5 or
622.08
Mbps
SDR source LVDS
synchronous
XAUI
4
None
3.125 Gbps
Clock data
recovery
(CDR)
1.5-V
PCML
8–21
Stratix Device Handbook, Volume 2
I/O Characteristics for XSBI, XGMII & XAUI
Software Implementation
You can use the Assignment Organizer in the Altera® Quartus® II
software to implement the I/O standards for a particular interface. For
example, set the I/O standard to LVDS for XSBI and to HSTL Class I for
XGMII. You can use the MegaWizard® Plug-In Manager to create the
PLLs and transmitter and receiver SERDES blocks for the XSBI
implementation and PLLs and DDR input and output circuitry for the
XGMII implementation. For more information on the Assignment
Organizer or MegaWizard Plug-In Manager, see the Quartus II Software
Help.
AC/DC Specifications
Table 8–10 lists the XSBI DC electrical characteristics, similar to Stratix
and Stratix GX devices, that are based on the ANSI/TIA-644 LVDS
specification.
Table 8–10. XSBI DC Specifications
Value
Parameter
Unit
Min
Output differential voltage (VOD)
Output offset voltage (VOS)
Output Impedance, single ended
Typ
Max
250
400 (1)
mV
1,125
1,375
mV
40
140
W
Change in VOD between ‘0’ and ‘1’
50
mV
Change in VOS between ‘0’ and ‘1’
50
mV
1,600
mV
Input voltage range (VI)
900
Differential impedance
100
W
Input differential voltage (VID)
100
600
mV
Receiver differential input impedance
70
130
W
50
mV
100
400
ps
Ground potential difference (between PCS and PMA)
Rise and fall times (20% to 80%)
Note to Table 8–10:
(1)
Larger VOD is possible for better signal intensity.
I/O characteristics for the 1.5-V HSTL standard for Stratix and Stratix GX
devices are shown in Figure 8–17 and comply with XGMII electrical
specifications available in 10-Gigabit Ethernet draft IEEE P802.3ae.
8–22
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
Figure 8–17. Electrical Characteristics for Stratix & Stratix GX Devices
(1.5-V HSTL Class I)
tf(min) = 1 V/ns
tz(min) = 1 V/ns
80% VSWING
VREF
VSWING = 1.0 V
Input
20% VSWING
tPD
VOH = VCCN − 0.4 V = 1.1 V
Output
VTT = VCCN/2 = 0.75 V
VOL = 0.4 V
VIH(AC) = 0.95 V
tPH2
Tri-Stated
Output
VTT = 0.75 V
VIL(AC) = 0.55 V
tPL2
HSTL AC Load Circuit for Class I
VTT
Output Buffer
RT = 50 Ω
VOUT
CL = 20pF
VIN
Input Buffer
VREF
HSTL AC Waveform & I/O Interface
Altera Corporation
July 2005
8–23
Stratix Device Handbook, Volume 2
I/O Characteristics for XSBI, XGMII & XAUI
Table 8–11 lists the DC specifications for Stratix and Stratix GX devices
(1.5-V HSTL Class I).
Table 8–11. DC Specifications for Stratix & Stratix GX Devices (1.5-V HSTL Class I) Note (1)
Minimum
Typical
Maximum
Units
VCCIO
Symbol
I/O supply voltage
Parameter
Conditions
1.4
1.5
1.6
V
VREF
Input reference voltage
0.68
0.75
0.9
V
VTT
Termination voltage
0.7
0.75
0.8
V
VIH (DC)
DC high-level input voltage
VREF + 0.1
VIL (DC)
DC low-level input voltage
–0.3
VIH (AC)
AC high-level input voltage
VREF + 0.2
VIL (AC)
AC low-level input voltage
II
Input pin leakage current
0 < VIN < VCCIO
–10
VOH
High-level output voltage
IOH = –8 mA
VCCIO – 0.4
VOL
Low-level output voltage
IOL = 8 mA
IO
Output leakage current
(when output is high Z)
GND ≤VOUT ≤
VCCIO
–10
V
VREF – 0.1
V
V
VREF – 0.2
V
10
μA
V
0.4
V
10
μA
Note to Table 8–11:
(1)
Drive strength is programmable according to values shown in the Stratix Device Family Data Sheet section of the
Stratix Device Handbook, Volume 1 or the Stratix GX Device Family Data Sheet section of the Stratix GX Device
Handbook, Volume 1.
10-Gigabit Ethernet MAC Core
As an Altera Megafunction Partners Program (AMPPSM) member,
MorethanIP provides a 10-Gigabit Ethernet MAC core for Altera
customers. MorethanIP’s 10-Gigabit Ethernet MAC core implements the
RS, the MAC layer, and user-programmable FIFO buffers for clock and
data decoupling.
Core Features
MorethanIP’s 10-Gigabit Ethernet MAC core provides the following
features:
■
■
Includes automatic pause frame generation (per IEEE 802.3 × 31) with
user-programmable pause quanta and pause-frame termination
Includes a programmable 48-bit MAC address with a promiscuous
mode option, and a programmable Ethernet frame length that
supports IEEE 802.1Q VLAN-tagged frames or jumbo Ethernet
frames
8–24
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing 10-Gigabit Ethernet Using Stratix & Stratix GX Devices
■
■
■
Supports broadcast traffic and multi-cast address resolution with a
64-entry hash table
Compliant with the IEEE802.3ae Draft 4.0
Implements XGMII, allowing it to interface to XAUI through a
10-Gigabit commercial SERDES
Conclusion
10-Gigabit Ethernet takes advantage of the existing Gigabit Ethernet
standard. With their rich I/O features, Stratix and Stratix GX devices
support the components of 10-Gigabit Ethernet as well as XSBI and
XGMII. Stratix GX devices also support XAUI. These interfaces are easily
implemented using the core architecture, differential I/O capabilities,
and superior PLLs of Stratix and Stratix GX devices.
Altera Corporation
July 2005
8–25
Stratix Device Handbook, Volume 2
I/O Characteristics for XSBI, XGMII & XAUI
8–26
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
9. Implementing SFI-4 in
Stratix & Stratix GX Devices
S52011-2.0
Introduction
The growth of the Internet has created huge bandwidth demands as
voice, video, and data push the limits of the existing wide area network
(WAN) backbones. To facilitate this bandwidth growth, speeds of OC-192
and higher are being deployed in WAN backbones (see Figure 9–1).
Today’s carrier backbone networks are supported by SONET/SDH
transmission technology. SONET/SDH is a transmission technology for
transporting optical signals at speeds ranging from 51 megabits per
second (Mbps) up to 40 gigabits per second (Gbps). SONET/SDH rings
make up the majority of the existing backbone infrastructure of the
Internet and the public switched telephone network (PSTN).
The Optical Internetworking Forum (OIF) standard SFI-4 is a 16-bit LVDS
interface used in an OC-192 SONET system to link the framer and the
serializer/deserializer (SERDES). Stratix® and Stratix GX devices support
the required data rates of up to 622.08 Mbps along with the one-to-one
relationship required between clock frequency and data rate. The fast
phase-locked loop (PLL) was designed to support the high clock
frequencies and the one-to-one relationship (between clock and data rate)
needed for interfaces such as XSBI and SFI-4. Support for SFI-4 extends
the reach of high-density programmable logic from the backplane to the
physical layer (PHY) devices.
This chapter focuses on the implementation of the interface between the
SERDES and the framer.
Figure 9–1. WAN Backbone
DWDM
40 G
SONET OC-48
SONET OC-192
~ ~
SDH STM-64
A SONET/SDH transmission network is composed of several pieces of
equipment, including terminal multiplexers, add-drop multiplexers, and
repeater and digital cross-connect systems. SONET is the standard used
in North America and SDH is the standard used outside North America.
Altera Corporation
July 2005
9–1
Introduction
The SONET/SDH specification outlines the frame format, multiplexing
method, synchronization method, and optical interface between the
equipment, as well as the specific optical interface.
SONET/SDH continues to play a key role in the next generation of
networks for many carriers. In the core network, the carriers offer services
such as telephone, dedicated leased lines, and Internet protocol (IP) data,
which are continuously transmitted. The individual data channels are not
transmitted on separate lines; instead, they are multiplexed into higher
speeds and transmitted on SONET/SDH networks at the corresponding
transmission speed.
Figure 9–2 shows a typical SONET/SDH line card. The system operates
as follows:
1.
The SONET/SDH line card first takes a high-speed serial optical
signal and converts it into a high-speed serial electrical signal. The
devices are called physical media dependent (PMD) devices.
2.
The system then recovers the clock from the electrical data using a
clock data recovery (CDR) unit.
3.
The SERDES parallelizes the data so that it can be manipulated
easily at lower clock rates.
4.
The interface between the SERDES and framer is called the SERDES
framer interface. The interface requirements are defined by the OIF.
5.
The framer identifies the beginning of the SONET/SDH frames and
monitors the performance of the system.
6.
The mapper following the framer maps asynchronous transfer
mode (ATM) cells, IP packets, or T/E carrier signals into the SONET
frame.
7.
The PHY-link layer interface provides a bus interface to packet/cell
processors or other link-layer devices.
9–2
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing SFI-4 in Stratix & Stratix GX Devices
Figure 9–2. SONET/SDH Line Card
7
1
Optical
Signal
OE Module
2
CDR
3
5
6
SERDES
SONET/SDH
Framer
SONET/SDH
Mapper/Protocol
Processor
Optical-Electrical
Conversion
SERDES Framer
Interface
4
To Packet
Processor &
Switch Fabric
Link Layer
Interface
The OIF has defined the electrical interface (SFI) between the
SONET/SDH framer and high-speed SERDES devices. To keep up with
evolving transmission speeds and technology enhancements, different
versions of electrical interfaces are defined. SFI-4 is the version of SFI that
acts as an interface between an OC-192 SERDES and SONET framer, as
shown in Figure 9–2. An aggregate of 9953.28 Mbps is transferred in each
direction. With their differential I/O capabilities, Stratix and Stratix GX
devices are ideally suited to support the framer side of the SFI-4 interface.
Support for SFI-4 extends the reach of high-density programmable logic
from the backplane to the PHY devices.
System Topology
The SFI-4 interface uses 16 channels of source-synchronous LVDS to
interface between a SONET framer and an OC-192 SERDES. Figure 9–3
shows the SFI-4 interface.
Altera Corporation
July 2005
9–3
Stratix Device Handbook, Volume 2
Introduction
Figure 9–3. SFI-4 Interface Signals
REFCLK
SONET Framer
Transmitter
OC-192 SERDES
Transmitter
TXDATA[15..0]
TXCLK
TXCLK_SRC
SONET Framer
Receiver
Recovered Clock
Receiver
RXDATA[15..0]
RXCLK
The framer transmits outbound data via TXDATA[15..0] and is
received at the SERDES using TXCLK. TXCLK is derived from
TXCLK_SRC, which is provided by the OC-192 SERDES. The framer
receives incoming data on RXDATA[15..0] from the OC-192 SERDES.
The data received is latched on the rising edge of RXCLK. Table 9–1
provides the data rates and clock frequencies specified by SFI-4. The
modes of TXCLK are specified by the SFI-4 standard. In required mode
(622 MHz clock mode or × 1 mode), TXCLK should run at 622.08 MHz. In
optional mode (311 MHz clock mode or × 2 mode), TXCLK should run at
311.04 MHz.
Table 9–1. SFI-4 Interface Data Rates & Clock Frequencies
Signal
Performance
TXDATA[15..0]
622.08 Mbps
TXCLK
622.08 MHz or 311.04 MHz
TXCLK_SRC
622.08 MHz
RXDATA[15..0]
622.08 Mbps
RXCLK
622.08 MHz
REFCLK
622.08 MHz
9–4
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing SFI-4 in Stratix & Stratix GX Devices
Interface Implementation in Stratix & Stratix GX Devices
The 16-bit full-duplex LVDS implementation of the framer part of the
SFI-4 interface is shown in Figure 9–4. Stratix devices support sourcesynchronous interfacing and LVDS differential signaling up to 840 Mbps.
Stratix devices have embedded SERDES circuitry for serial and parallel
data conversion.
The source-synchronous I/O implemented in Stratix GX devices
optionally includes dynamic phase alignment (DPA). DPA automatically
and continuously tracks fluctuations caused by system variations and
self-adjusts to eliminate the phase skew between the multiplied clock and
the serial data, allowing for data rates of 1 Gbps. In non DPA mode the
I/O behaves similarly to that of the Stratix I/O. This document assumes
that DPA is disabled. However, it is simple to implement the same system
with DPA enabled to take advantage of its features. For more information
on DPA, see the Stratix GX Transceivers chapter in the Stratix GX Device
Handbook, Volume 1.
The fast PLL enables 622.08 Mbps data transmission by transmitting and
receiving a differential clock at rates of up to 645 MHz. The clocks
required in the SERDES for parallel and serial data conversion can be
configured from the received RXCLK (divided down), the TXCLK_SRC
(divided down), or the asynchronous core clock. See Figure 9–4.
Altera Corporation
July 2005
9–5
Stratix Device Handbook, Volume 2
Introduction
Figure 9–4. Implementation of SFI-4 Interface Using Stratix & Stratix GX Devices
REFCLK
OC-192
SERDES
128
Data
TXDATA[15..0]
Transmitter
SERDES
Clk
TXCLK
Stratix Framer
PLL1
Stratix &
Stratix GX
Logic Array
×1
TXCLK_SRC
÷8
Transmitter
Transmitter
Receiver
PLL2
Phase Shift
÷8
Clk
180˚
Receiver
SERDES
RXCLK
RXDATA[15..0]
Data
128
Receiver
f
For details on differential I/O buffers, SERDES, and clock dividers using
PLLs, see the High-Speed Differential I/O Interfaces in Stratix Devices
chapter in the Stratix Device Handbook or the Stratix GX Device Handbook.
Figure 9–5 shows the transmitter block (from Figure 9–4) of the SFI-4
framer interface implemented in Stratix and Stratix GX devices. The data
starts in the logic array and goes into the Stratix and Stratix GX SERDES
block. The transmitter SERDES of the framer converts the parallel data to
serial data for the 16 TXDATA channels (TXDATA[15..0]). A fast PLL is
used to generate TXCLK from TXCLK_SRC. The fast PLL keeps the
TXDATA and TXCLK edge-aligned. A divided down (÷8) clock generated
from TXCLK_SRC is used to convert the parallel data to serial in the
transmitter SERDES. The divided down clock also clocks some of the
logic in the logic array.
9–6
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing SFI-4 in Stratix & Stratix GX Devices
Figure 9–5. Framer Transmitter Interface in Stratix & Stratix GX Devices
Stratix & Stratix GX SFI-4 Transmitter
Stratix & Stratix GX SERDES
Parallel
Register
8
Parallel-to-Serial
Register
CH0
Stratix & Stratix GX
Logic Array
TXDATA[0]
622 Mbps
OC-192
SERDES
8
CH15
TXDATA[15]
TXCLK
622MHz
÷J
Fast PLL
×W
622 MHz
W=1
J=8
TXCLK_SRC
622 MHz
Figure 9–6 shows the receiver block (from Figure 9–4) of the SFI-4 framer
interface implemented in Stratix and Stratix GX devices.
RXDATA[15..0] is received from the OC-192 SERDES on the differential
I/O pins of the Stratix or Stratix GX device. The receiver SERDES
converts the high-speed serial data to parallel. You can generate the
clocks required in the SERDES for parallel and serial data conversion
from the received RXCLK. RXCLK is inverted (phase-shifted by 180° ) to
capture received data. While normal I/O operation guarantees that data
is captured, it does not guarantee the parallelization boundary, which is
randomly determined based on the power up of both communicating
devices. The SERDES has embedded data realignment capability, which
can be used to save logic elements (LEs).
Altera Corporation
July 2005
9–7
Stratix Device Handbook, Volume 2
Introduction
Figure 9–6. Framer Receiver Interface in Stratix & Stratix GX Devices
Stratix & Stratix GX SFI-4 Receiver
Stratix & Stratix GX SERDES
Parallel
Register
8
Serial-to-Parallel
Register
CH0
RXDATA[0]
Stratix & Stratix GX
Logic Array
OC-192
SERDES
8
CH15
RXDATA[15]
622 Mbps
÷J
Fast PLL
×W
622 MHz
W=1
J=8
RXCLK
622 MHz
Note to Figure 9–6:
(1)
The figure shows Stratix GX DPA disabled.
f
For more information on the byte-alignment feature in Stratix and
Stratix GX devices, see the High-Speed Differential I/O Interfaces in Stratix
Devices chapter in the Stratix Device Handbook or the Stratix GX Device
Handbook.
9–8
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing SFI-4 in Stratix & Stratix GX Devices
Tables 9–2 and 9–3 list the number of SFI-4 cores that can be implemented
in Stratix and Stratix GX devices. See the High-Speed Differential I/O
Interfaces in Stratix Devices chapter in the Stratix Device Handbook or the
Stratix GX Device Handbook for the package type and the maximum
number of channels supported by each package.
Table 9–2. Stratix SFI-4 Core Support
Number of LVDS
Channels
Stratix Device
(Receiver/Transmitter)
(1)
Number of PLLs
Number of SFI-4
Interfaces
(Maximum)
EP1S10
44/44
4
2
EP1S20
66/66
4
2
EP1S25
78/78
4
2
EP1S30
82/82
8
4
EP1S40
90/90
8
4
EP1S60
116/116
8
4
EP1S80
152/156
8
4
Note to Table 9–2:
(1)
The LVDS channels can go up to 840 Mbps (or 1 Gbps using DPA in Stratix GX
devices). This number includes both high speed and low speed channels. The
high speed LVDS channels can go up to 840 Mbps. The low speed LVDS channels
can go up to 462 Mbps. The High-Speed Differential I/O Support chapters in the
Stratix Device Handbook, Volume 1 and the Stratix GX Device Handbook, Volume 1
and the device pin-outs on the web (www.altera.com) specify which channels are
high and low speed.
Table 9–3. Stratix GX SFI-4 Core Support
Number of LVDS
Channels
(Receiver/Transmitter)
(1)
Number of PLLs
Number of SFI-4
Interfaces
(Maximum)
EP1SGX10
22/22
2
1
EP1SGX25
39/39
2
2
EP1SGX40
45/45
4
2
Stratix GX
Device
Note to Table 9–3:
(1)
Altera Corporation
July 2005
The LVDS channels can go up to 840 Mbps, or 1 Gbps using DPA. This number
includes both high speed and low speed channels. The high speed LVDS channels
can go up to 840 Mbps. The low speed LVDS channels can go up to 462 Mbps. The
High-Speed Differential I/O Support chapter in the Stratix Device Handbook, Volume
1 and the Stratix GX Device Handbook, Volume 1 and the device pin-outs on the web
(www.altera.com) specify which channels are high and low speed.
9–9
Stratix Device Handbook, Volume 2
Introduction
AC Timing Specifications
Figures 9–7 through 9–9 and Tables 9–4 through 9–6 illustrate the timing
characteristics of SFI-4 at the framer. Stratix and Stratix GX devices
support all the timing requirements needed to support transmitter and
receiver functions of a SFI-4 framer; only framer-related timing
specifications are applicable.
f
For details on the timing specifications of LVDS I/O standards in Stratix
and Stratix GX devices, see the Stratix Device Family Data Sheet section of
the Stratix Device Handbook, Volume 1 and the High-Speed Differential I/O
Interfaces in Stratix Devices chapter or the Stratix GX Device Family Data
Sheet section of the Stratix GX Device Handbook, Volume 1 and the HighSpeed Differential I/O Interfaces in Stratix Devices chapter
Figure 9–7 shows the timing diagram for the Stratix and Stratix GX
framer transmitter × 1 (622 MHz clock) mode.
Figure 9–7. Framer Transmitter × 1 (622 MHz Clock) Mode Timing Diagram
Tperiod
Valid
Data
TX_DATA[15..0]
Tcq_pre
Tcq_post
Tsetup
Thold
Table 9–4 lists the timing specifications for the SFI-4 framer transmitter in
× 1 (622 MHz clock) mode.
Table 9–4. SFI-4 Framer Transmitter × 1 (622 MHz Clock) Mode Timing Specifications
Value
Parameter
Unit
Min
Typ
Max
1,608
TX_CLK (Tperiod)
ps
Data invalid window before the rising edge (Tcq_pre)
200
ps
Data invalid window after the rising edge (Tcq_post)
200
ps
TX_CLK duty cycle
Framer transmitter channel-to-channel skew
9–10
Stratix Device Handbook, Volume 2
40
60
%
200
ps
Altera Corporation
July 2005
Implementing SFI-4 in Stratix & Stratix GX Devices
Figure 9–8 shows the timing diagram for the SFI-4 framer transmitter in
× 2 (311 MHz clock) mode
Figure 9–8. Framer Transmitter × 2 (311 MHz Clock) Mode Timing Diagram
Tperiod/2
TX_CLK(P)
Valid
Data
TX_DATA[15..0]
Tcq_pre
Valid
Data
Tcq_post
Table 9–5 lists the timing specifications for the SFI-4 framer transmitter in
× 2 (311 MHz clock) mode.
Table 9–5. SFI-4 Framer Transmitter × 2 (311 MHz Clock) Mode Timing Specifications
Value
Parameter
Unit
Min
Typ
Max
3,215
TX_CLK (Tperiod)
ps
Data invalid window before the rising edge (Tcq_pre)
200
ps
Data invalid window after the rising edge (Tcq_post)
200
ps
52
%
200
ps
48
TX_CLK duty cycle
Framer transmitter channel-to-channel skew
Figure 9–9 shows the timing diagram for the SFI-4 framer receiver.
Figure 9–9. Framer Receiver Timing Diagram
Tperiod
Tperiod
RX_CLK(P)
RX_CLK(P)
RX_DATA[15..0]
Tcq_pre
Altera Corporation
July 2005
Valid
Data
Tcq_post
RX_DATA[15..0]
Tsetup
Thold
Transmitter Channel-to-Channel
Skew/2
RSKM
Sampling Window
RSKM
Transmitter Channel-to-Channel
Skew/2
9–11
Stratix Device Handbook, Volume 2
Introduction
Table 9–6 lists the timing specifications for the SFI-4 framer receiver.
Table 9–6. Framer Receiver Timing Specifications
Value
Parameter
Unit
Min
Typ
Max
1,608
RX_CLK (Tperiod)
Data invalid window before the rising edge (Tcq_pre)
Data invalid window after the rising edge (Tcq_post)
RX_CLK duty cycle
45
Data set-up time (Tsetup)
300
ps
200
ps
200
ps
55
%
ps
Data hold time (Thold)
300
ps
Framer sampling window
600
ps
Receiver skew margin (RSKM)
304
ps
Electrical Specifications
SFI-4 uses LVDS as a high-speed data transfer mechanism to implement
the SFI-4 interface. Table 9–7 lists the DC electrical characteristics for the
interface, which are based on the IEEE Std. 1596.3-1996 7 specification.
For more information on the voltage specification of LVDS I/O standards
in Stratix and Stratix GX devices, see the Stratix Device Family Data Sheet
section of the Stratix Device Handbook, Volume 1 and the High-Speed
Differential I/O Interfaces in Stratix Devices chapter or the Stratix GX Device
Family Data Sheet section of the Stratix GX Device Handbook, Volume 1 and
the High-Speed Differential I/O Interfaces in Stratix Devices chapter.
9–12
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Implementing SFI-4 in Stratix & Stratix GX Devices
Table 9–7. Framer LVDS DC Specifications
Value
Parameter
Unit
Min
Typ
Max
250
600 (1)
mV
1,125
1,375
mV
40
140
W
Change in VOD between ‘0’ and '1'
50
mV
Change in VOD between '1' and '0'
50
mV
2,400
mV
Output differential voltage (VOD)
Output offset voltage (VOS)
Output Impedance, single ended
Input voltage range (VI)
0
Differential impedance
100
W
Input differential voltage (VID)
100
600
mV
Receiver differential input impedance
70
130
W
50
mV
100
400
ps
Ground potential difference (between PCS and PMA)
Rise and fall times (20% to 80%)
Note to Table 9–7:
(1)
The IEEE standard requires 400 mV. A larger swing is encouraged, but not required.
Software Implementation
The SFI-4 interface uses a 16-bit LVDS I/O interface. The Altera®
Quartus® II software version 2.0 supports Stratix and Stratix GX devices,
allowing you to implement LVDS I/O buffers through the Quartus II
Assignment Organizer.
f
For information on the Quartus II Assignment Organizer, see the
Quartus II Software Help.
Conclusion
SFI-4 is the standard interface between SONET framers and optical
SERDES for OC-192 interfaces. With embedded SERDES and fast PLLs,
Stratix and Stratix GX devices can easily support the SFI-4 framer
interface, enabling
10-Gbps (OC-192) data transfer rates. Stratix and Stratix GX I/O supports
the required data rates of up to 622.08 Mbps. Stratix and Stratix GX fast
PLLs are designed to support the high clock frequencies and one-to-one
relationship needed for interfaces such as XSBI and SFI-4. Stratix and
Stratix GX devices can support multiple SFI-4 functions on one device.
Altera Corporation
July 2005
9–13
Stratix Device Handbook, Volume 2
Introduction
9–14
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
10. Transitioning APEX
Designs to Stratix &
Stratix GX Devices
S52012-3.0
Introduction
Stratix® and Stratix GX devices are Altera’s next-generation, system-ona-programmable-chip (SOPC) solution. Stratix and Stratix GX devices
simplify the block-based design methodology and bridge the gap
between system bandwidth requirements and programmable logic
performance.
This chapter highlights the new features in the Stratix and Stratix GX
devices and provides assistance when transitioning designs from
APEXTM II or APEX 20K devices to the Stratix or Stratix GX architecture.
You should be familiar with the APEX II or APEX 20K architecture and
available device features before using this chapter. Use this chapter in
conjunction with the Stratix Device Family Data Sheet section of the Stratix
Device Handbook, Volume 1 or the Stratix GX Device Family Data Sheet
section of the Stratix GX Device Handbook, Volume 1.
General
Architecture
Stratix and Stratix GX devices offer many new features and architectural
enhancements. Enhanced logic elements (LEs) and the MultiTrackTM
interconnect structure offer reduced resource utilization and
considerable design performance improvement. The MultiTrack
interconnect uses DirectDriveTM technology to ensure the availability of
deterministic routing resources for any design block, regardless of its
placement within the device.
All architectural changes between Stratix and Stratix GX and APEX II or
APEX 20K devices described in this section do not require any design
changes. However, you must resynthesize your design and recompile in
the Quartus® II software to target Stratix and Stratix GX devices.
Altera Corporation
July 2005
10–1
General Architecture
Logic Elements
Stratix and Stratix GX device LEs include several new, advanced features
that improve design performance and reduce logic resource consumption
(see Table 10–1). The Quartus II software automatically uses these new
LE features to improve device utilization.
Table 10–1. Stratix & Stratix GX LE Features
Feature
Function
Register chain interconnects Direct path between the register output
of an LE and the register input of an
adjacent LE within the same logic array
block (LAB)
Benefit
„ Conserves LE resources
„ Provides fast shift register
implementation
„ Saves local interconnect routing
resources within an LAB
Look-up table (LUT) chain
interconnects
Direct path between the combinatorial „ Allows LUTs within the same LAB to
output of an LE and the fast LUT input cascade together for high-speed wide
of an adjacent LE within the same LAB fan-in functions, such as wide XOR
operations
„ Bypasses local interconnect for
faster performance
Register-to-LUT feedback
path
Allows the register output to feed back
into the LUT of the same LE, such that
the register is packed with its own fanout LUT
„ Enhanced register packing mode
„ Uses resources more efficiently
Dynamic arithmetic mode
Uses one set of LEs for implementing
both an adder and subtractor
„ Improves performance for functions
that switch between addition and
subtraction frequently, such as
correlators
Carry-select chain
Calculates outputs for a possible carry- „ Gives immediate access to result for
in of 1 or 0 in parallel
both a carry-in of 1 or 0
„ Increases speed of carry functions
for high-speed operations, such as
counters, adders, and comparators
Asynchronous clear and
asynchronous preset
function
Supports direct asynchronous clear
and preset functions
„ Conserves LE resources
„ Does not require additional logic
resources to implement NOT-gate
push-back
In addition to the new LE features described in Table 10–1, there are
enhancements to the chains that connect LEs together. Carry chains are
implemented vertically in Stratix and Stratix GX devices, instead of
horizontally as in APEX II and APEX 20K devices, and continue across
rows, instead of across columns, as shown in Figure 10–1. Also note that
the Stratix and Stratix GX architectures do not support the cascade
primitive. Therefore, the Quartus II Compiler automatically converts
10–2
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
cascade primitives in APEX II and APEX 20K designs to a wire primitive
when compiled for Stratix and Stratix GX devices. These architectural
changes are transparent to the user and do not require design changes.
Figure 10–1. Carry Chain Implementation in APEX II & APEX 20K Devices vs.
Stratix & Stratix GX Devices
APEX II & APEX 20K Devices
Stratix Devices
Carry Chains
Carry-Select
Chains
LABs (with 10 LEs Each)
MultiTrack Interconnect
Stratix and Stratix GX devices use the MultiTrack interconnect structure
to provide a high-speed connection between logic resources using
performance-optimized routing channels of different lengths. This
feature maximizes overall design performance by placing critical paths
on routing lines with greater speed, resulting in minimal propagation
delay.
Altera Corporation
July 2005
10–3
Stratix Device Handbook, Volume 2
General Architecture
Stratix and Stratix GX device MultiTrack interconnect resources are
described in Table 10–2.
Table 10–2. Stratix & Stratix GX Device MultiTrack Interconnect Resources
Routing Type
Row
Interconnect
Direct link
Span
Adjacent LABs and/or blocks
Row
R4
Four LAB units horizontally
Row
R8
Eight LAB units horizontally
Row
R24
Horizontal routing across the width of the device
Column
C4
Four LAB units vertically
Column
C8
Eight LAB units vertically
Column
C16
Vertical routing across the length of the device
Direct link routing saves row routing resources while providing fast
communication paths between resource blocks. Direct link interconnects
allow an LAB, digital signal processing (DSP) block, or TriMatrixTM
memory block to drive data into the local interconnect of its left and right
neighbors. LABs, DSP blocks, and TriMatrix memory blocks can also use
direct link interconnects to drive data back into themselves for feedback.
The Quartus II software automatically uses these routing resources to
enhance design performance.
f
For more information about LE architecture and the MultiTrack
interconnect structure in Stratix and Stratix GX devices, see the Stratix
Device Family Data Sheet section of the Stratix Device Handbook, Volume 1
or the Stratix GX Device Family Data Sheet section of the Stratix GX Device
Handbook, Volume 1.
DirectDrive Technology
When using APEX II or APE 20K devices, you must place critical paths in
the same MegaLABTM column to improve performance. Additionally, you
should place critical paths in the same MegaLAB structure for optimal
performance. However, this restriction does not exist in Stratix and
Stratix GX devices because they do not contain MegaLAB structures.
With the new DirectDriveTM technology in Stratix and Stratix GX devices,
the actual distance between the source and destination of a path is the
most important criteria for meeting timing performance. DirectDrive
technology ensures that the same routing resources are available to each
design block, regardless of its location in the device.
10–4
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
Architectural Element Names
The architectural element naming system within Stratix and Stratix GX
devices differs from the row-column coordinate system (for example,
LC1_A2, LAB_B1) used in previous Altera device families. Stratix and
Stratix GX devices uses a new naming system based on the X-Y
coordinate system, (X, Y). A number (N) designates the location within the
block where the logic resides, such as LEs within an LAB. Because the
Stratix and Stratix GX architectures are column-based, this naming
simplifies location assignments. Stratix and Stratix GX architectural
blocks include:
■
■
■
■
■
■
LAB: logic array block
DSP: digital signal processing block
DSPOUT: adder/subtractor/accumulator or summation block of the
DSP block
M512: 512-bit memory block
M4K: 4-Kbit memory block
M-RAM: 512-Kbit memory block
Elements within architectural blocks include:
■
■
■
■
■
■
Altera Corporation
July 2005
LE: logic element
IOC: I/O element
PLL: phase-locked loop
DSPMULT: DSP block multiplier
SERDESTX: transmitter serializer/deserializer
SERDESRX: receiver serializer/deserializer
10–5
Stratix Device Handbook, Volume 2
General Architecture
Table 10–3 highlights the new location syntax used for Stratix and
Stratix GX devices.
Table 10–3. Stratix & Stratix GX Location Assignment Syntax
Architectural
Elements
Example of Location Syntax
Element Name
Location Syntax
Location
Description
Blocks
LAB, DSP,
<element_name>_X<number> LAB_X1_Y1
DSPOUT, M512, _Y<number>
M4K, M-RAM
Logic
LE, IOC, PLL,
DSPMULT,
SERDESTX,
SERDESRX
<element_name>_X<number> LC_X1_Y1_N0
_Y<number>_N<number>
Designates the first
LE, N0, in the LAB
located in row 1,
column 1
Pins (1)
I/O pins
pin_<pin_label>
Pin 5
pin_5
Designates the LAB in
row 1, column 1
Note to Table 10–3:
(1)
You can make assignments to I/O pads using IOC_X<number>_Y<number>_N<number>.
Use the following guidelines with the new naming system:
■
■
■
■
■
The anchor point, or origin, in Stratix and Stratix GX devices is in the
bottom-left corner, instead of the top-left corner as in APEX II and
APEX 20K devices.
The anchor point, or origin, of a large block element (e.g., a M-RAM
or DSP block) is also the bottom-left corner.
All numbers are zero-based, meaning the origin at the bottom-left of
the device is X0, Y0.
The I/O pins constitute the first and last rows and columns in the
X-Y coordinates. Therefore, the bottom row of pins resides in
X<number>, Y0, and the first left column of pins resides in X0,
Y<number>.
The sub-location of elements, N, numbering begins at the top.
Therefore, the LEs in an LAB are still numbered from top to bottom,
but start at zero.
Figure 10–2 show the Stratix and Stratix GX architectural element
numbering convention. Figure 10–3 displays the floorplan view in the
Quartus II software.
10–6
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
Figure 10–2. Stratix & Stratix GX Architectural Elements Note (1)
M4K RAM Blocks are
Two Units Wide and
One Unit High
LAB
(1,18)
LAB
(11,18)
M512
(12,18)
LAB
(13,18)
M4K
(14,18)
LAB
(16,18)
LAB
(1,17)
LAB
(11,17)
M512
(12,17)
LAB
(13,17)
M4K
(14,17)
LAB
(16,17)
LAB
(1,16)
LAB
(11,16)
M512
(12,16)
LAB
(13,16)
M4K
(14,16)
LAB
(16,16)
LAB
(1,15)
LAB
(11,15)
M512
(12,15)
LAB
(13,15)
M4K
(14,15)
LAB
(16,15)
M4K
(14,14)
M4K
(14,13)
Mega RAM Block is
13 Units Wide and
13 Units High
DSP Block (17,1)
is Two Units Wide
and Eight Units High
DSPMULT
(17,7,0)
and
(17,7,1)
(3)
DSPMULT
(17,5,0)
and
(17,5,1)
LAB
(16,14)
DSPOUT
(18,1,0)
and
(18,1,7)
LAB
(16,13)
DSPMULT
(17,3,0)
and
(17,3,1)
Mega RAM (1,2)
M4K
(14,2)
Pins
LAB
(16,2)
DSPMULT
(17,1,0)
and
(17,1,1)
(2)
PLL
(0,1,0)
LAB
(1,1)
LAB
(11,1)
M512
(12,1)
M4K
(14,1)
LAB
(13,1)
(2)
LAB
(16,1)
(2)
Origin (0, 0)
Notes to Figure 10–2:
(1)
(2)
(3)
Figure 10–2 shows part of a Stratix and Stratix GX device.
Large block elements use their lower-left corner for the coordinate location.
The Stratix GX architectural elements include transceiver blocks on the right side of the device.
Altera Corporation
July 2005
10–7
Stratix Device Handbook, Volume 2
TriMatrix Memory
Figure 10–3. LE Numbering as Shown in the Quartus II Software
TriMatrix
Memory
TriMatrix memory has three different sizes of memory blocks, each
optimized for a different purpose or application. M512 blocks consist of
512 bits plus parity (576 bits), M4K blocks consist of 4K bits plus parity
(4,608 bits), and M-RAM blocks consist of 512K bits plus parity
(589,824 bits). This new structure differs from APEX II and APEX 20K
devices, which feature uniformly sized embedded system blocks (ESBs)
either 4 Kbits (APEX II devices) or 2 Kbits (APEX 20K devices) large.
Stratix and Stratix GX TriMatrix memory blocks give you advanced
control of each memory block, with features such as byte enables, parity
bit storage, and shift-register mode, as well as mixed-port width support
and true dual-port mode operation.
10–8
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
Table 10–4 compares TriMatrix memory with ESBs.
Table 10–4. Stratix & Stratix GX TriMatrix Memory Blocks vs. APEX II & APEX 20K ESBs
Stratix & Stratix GX
Features
APEX II ESB
M512 RAM
Size (bits)
576
M4K RAM
4,608
APEX 20K ESB
M-RAM
589,824
4,096
2,048
Parity bits
Yes
Yes
Yes
No
No
Byte enable
No
Yes
Yes
No
No
True dual-port
mode
No
No
Yes
Yes
Yes
Includes support Includes support Includes support
for mixed width for mixed width for mixed width
Embedded shift
register
Yes
Yes
No
No
No
Dedicated
contentaddressable
memory (CAM)
support
No
No
No
Yes
Yes
Pre-loadable
initialization with a
.mif (1)
Yes
Yes
No
Yes
Yes
Packed mode (2)
No
Yes
No
Yes
Yes
Feed-through
behavior
Rising edge
Rising edge
Rising edge
Falling edge
Falling edge
Output power-up
condition
Powers up
cleared even if
using a .mif (1)
Powers up
cleared even if
using a .mif (1)
Powers up with
unknown state
Powers up
cleared or to
initialized value,
if using a .mif (1)
Powers up
cleared or to
initialized value,
if using a .mif (1)
Notes to Table 10–4:
(1)
(2)
.mif: Memory Initialization File.
Packed mode refers to combining two single-port RAM blocks into a single RAM block that is placed into true
dual-port mode.
Stratix and Stratix GX TriMatrix memory blocks only support pipelined
mode, while APEX II and APEX 20K ESBs support both pipelined and
flow-through modes. Since all TriMatrix memory blocks can be
pipelined, all input data and address lines are registered, while outputs
can be either registered or combinatorial. You can use Stratix and
Stratix GX memory block registers to implement input and output
registers without utilizing additional resources. You can compile designs
containing pipelined memory blocks (inputs registered) for Stratix and
Stratix GX devices without any modifications. However, if an APEX II or
Altera Corporation
July 2005
10–9
Stratix Device Handbook, Volume 2
TriMatrix Memory
APEX 20K design contains flow-through memory, you must modify the
memory modules to target the Stratix and Stratix GX architectures (see
“Memory Megafunctions” on page 10–12 for more information).
f
For more information about TriMatrix memory and converting flowthrough memory modules to pipelined, see the TriMatrix Embedded
Memory Blocks in Stratix & Stratix GX Devices chapter in the Stratix GX
Device Handbook and AN 210: Converting Memory from Asynchronous to
Synchronous for Stratix & Stratix GX Designs.
Same-Port Read-During-Write Mode
In same-port read-during-write mode, the RAM block can be in singleport, simple dual-port, or true dual-port mode. One port from the RAM
block both reads and writes to the same address location using the same
clock. When APEX II or APEX 20K devices perform a same-port readduring-write operation, the new data is available on the falling edge of
the clock cycle on which it was written, as shown in Figure 10–4. When
Stratix and Stratix GX devices perform a same-port read-during-write
operation, the new data is available on the rising edge of the same clock
cycle on which it was written, as shown in Figure 10–5. This holds true for
all TriMatrix memory blocks.
Figure 10–4. Falling Edge Feed-Through Behavior
(APEX II & APEX 20K Devices) Note (1)
inclock
data_in
A
B
wren
data_out
Old
A
Note to Figure 10–4:
(1)
Figures 10–4 and 10–5 assume that the address stays constant throughout and that
the outputs are not registered.
10–10
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
Figure 10–5. Rising Edge Feed-Through Behavior
(Stratix & Stratix GX Devices) Note (1)
inclock
data_in
A
B
wren
data_out Old
A
Note to Figure 10–5:
(1)
Figures 10–4 and 10–5 assume that the address stays constant throughout and that
the outputs are not registered.
Mixed-Port Read-During-Write Mode
Mixed-port read-during-write mode occurs when a RAM block in simple
or true dual-port mode has one port reading and the other port writing to
the same address location using the same clock. In APEX II and
APEX 20K designs, the ESB outputs the old data in the first half of the
clock cycle and the new data in the second half of the clock cycle, as
indicated by Figure 10–6.
Figure 10–6. Mixed-Port Feed-Through Behavior
(APEX II & APEX 20K Devices) Note (1)
inclock
Port A
data_in
A
B
Port A
wren
Port B
wren
Port B
data_out
Old
A
B
Note to Figure 10–6:
(1)
Figure 10–6 assumes that outputs are not registered.
Stratix and Stratix GX device RAM outputs the new data on the rising
edge of the clock cycle immediately after the data was written. When you
use Stratix and Stratix GX M512 and M4K blocks, you can choose whether
to output the old data at the targeted address or output a don’t care value
during the clock cycle when the new data is written. M-RAM blocks
Altera Corporation
July 2005
10–11
Stratix Device Handbook, Volume 2
TriMatrix Memory
always output a don’t care value. Figures 10–7 and 10–8 show the feedthrough behavior of the mixed-port mode. You can use the altsyncram
megafunction to set the output behavior during mixed-port read-duringwrite mode.
Figure 10–7. Mixed-Port Feed-Through Behavior (OLD_DATA) Note (1)
inclock
addressA and
addressB
Port A
data_in
Address Q
A
B
Port A
wren
Port B
wren
Port B
data_out
Old
A
B
Note to Figure 10–7:
(1)
Figures 10–7 and 10–8 assume that the address stays constant throughout and that
the outputs are not registered.
Figure 10–8. Mixed-Port Feed-Through Behavior (DONT_CARE) Note (1)
inclock
addressA and
addressB
Port A
data_in
Address Q
A
B
Port A
wren
Port B
wren
Port B
data_out
Unknown
B
Note to Figure 10–8:
(1)
Figures 10–7 and 10–8 assume that the address stays constant throughout and that
the outputs are not registered.
Memory Megafunctions
To convert RAM and ROM originally targeting the APEX II or APEX 20K
architecture to Stratix or Stratix GX memory, specify Stratix or Stratix GX
as the target family in the MegaWizard Plug-In Manager. The software
10–12
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
updates the memory module for the Stratix or Stratix GX architecture and
instantiates the new synchronous memory megafunction, altsyncram,
which supports both RAM and ROM blocks in the Stratix and Stratix GX
architectures.
FIFO Conditions
First-in first-out (FIFO) functionality is slightly different in Stratix and
Stratix GX devices compared to APEX II and APEX 20K devices. Stratix
and Stratix GX devices do not support simultaneous reads and writes
from an empty FIFO buffer. Also, Stratix and Stratix GX devices do not
support the lpm_showahead parameter when targeting a FIFO buffer
because the TriMatrix memory blocks are synchronous. The
lpm_showahead parameter for APEX II and APEX 20K devices puts the
FIFO buffer in “read-acknowledge” mode so the first data written into the
FIFO buffer immediately flows through to the output. Other than these
two differences, all APEX II and APEX 20K FIFO functions are fully
compatible with the Stratix and Stratix GX architectures.
Design Migration Mode in Quartus II Software
The Quartus II software features a migration mode for simplifying the
process of converting APEX II and APEX 20K memory functions to the
Stratix or Stratix GX architecture. If the design can use the Stratix or
Stratix GX altsyncram megafunction as a replacement for a previous
APEX II or APEX 20K memory function while maintaining functionally
similar behavior, the Quartus II software automatically converts the
memory. The software produces a warning message during compilation
reminding you to verify that the design migrated correctly.
For memory blocks with all inputs registered, the existing megafunction
is converted to the new altsyncram megafunction. The software
generates a warning when the altsyncram megafunction is
incompatible. For example, a RAM block with all inputs registered except
the read enable compiles with a warning message indicating that the
read-enable port is registered.
You can suppress warning messages for the entire project or for
individual memory blocks by setting the
SUPPRESS_MEMORY_CONVERSION_WARNINGS parameter to “on” as a
global parameter by selecting Assignment Organizer (Tools menu). In
the Assignment Organizer window, click Parameters in the Assignment
Categories box. Type SUPPRESS_MEMORY_CONVERSION_WARNINGS in
the Assignment Name box and type ON in the Assignment Setting box.
To suppress these warning messages on a per-memory-instance basis, set
the SUPPRESS_MEMORY_CONVERSION_WARNINGS parameter in the
Assignment Organizer to “on” for the memory instance.
Altera Corporation
July 2005
10–13
Stratix Device Handbook, Volume 2
TriMatrix Memory
If the functionality of the APEX II or APEX 20K memory megafunction
differs from the altsyncram functionality and at least one clock feeds
the memory megafunction, the Quartus II software converts the APEX II
or APEX 20K memory megafunction to the Stratix or Stratix GX
altsyncram megafunction. This conversion is useful for an initial
evaluation of how a design might perform in Stratix or Stratix GX devices
and should only be used for evaluation purposes. During this process, the
Quartus II software generates a warning that the conversion may be
functionally incorrect and timing results may not be accurate. Since the
functionality may be incorrect and the compilation is only intended for
comparative purposes, the Quartus II software does not generate a
programming file. A functionally correct conversion requires manually
instantiating the altsyncram megafunction and may require additional
design changes.
If the previous memory function does not have a clock (fully
asynchronous), the fitting-evaluation conversion results in an error
message during compilation and does not successfully convert the
design.
f
See AN 210: Converting Memory from Asynchronous to Synchronous for
Stratix & Stratix GX Designs for more information.
Table 10–5 summarizes the possible scenarios when using design
migration mode and the resulting behavior of the Quartus II software.
The most common cases where design-migration mode may have
difficulty converting the existing design are when:
■
A port is reading from an address that is being written to by another
port (mixed-port read-during-write mode). If both ports are using
the same clock, the read port in Stratix and Stratix GX devices do not
see the new data until the next clock cycle, after the new data was
written.
10–14
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
■
There are differences in power-up behavior between APEX II,
APEX 20K, and Stratix and Stratix GX devices. You should manually
account for these differences to maintain desired operation of the
system.
Table 10–5. Migration Mode Summary
Memory
Configuration
Single-port
Conditions
Possible
Instantiated
Megafunctions
All inputs are registered. altram
Quartus II Warning
Message(s)
Programming
File
Generated
Power-up differences. (1)
Yes
Power-up differences.
Mixed-port read- duringwrite. (1)
Yes
Yes
altrom
lpm_ram_dq
lpm_ram_io
lpm_rom
All inputs are registered. altdpram
Multi-port (two-,
three-, or four-port
lpm_ram_dp
functions)
altqpram
alt3pram
Dual-port
Read-enable ports are
unregistered.
Other inputs registered.
altdpram
lpm_ram_dp
altqpram
alt3pram
Power-up differences.
Mixed-port read- duringwrite.
Read enable will be
registered. (1)
Dual-port
Any other unregistered
port except read-enable
ports.
Clock available.
altdpram
lpm_ram_dp
altqpram
alt3pram
Compile for fitting- evaluation No
purposes.
Single-port
At least one registered
input.
Clock available.
altram
lpm_ram_dq
lpm_ram_io
Compile for fitting- evaluation No
purposes.
No clock
No clock.
altram
altrom
altdpram
altqpram
alt3pram
altdpram
lpm_ram_dq
lpm_ram_io
lpm_rom
lpm_ram_dp
lpm_ram_dp
Error – no conversion
possible.
No
Note to Table 10–5:
(1)
If the SUPPRESS_MEMORY_COUNVERSION_WARNINGS parameter is turned on, the Quartus II software does not
issue these warnings.
Altera Corporation
July 2005
10–15
Stratix Device Handbook, Volume 2
DSP Block
DSP Block
Stratix and Stratix GX device DSP blocks outperform LE-based
implementations for common DSP functions. Each DSP block contains
several multipliers that can be configured for widths of 9, 18, or 36 bits.
Depending on the mode of operation, these multipliers can optionally
feed an adder/subtractor/accumulator or summation unit.
You can configure the DSP block’s input registers to efficiently
implement shift registers for serial input sharing, eliminating the need for
external shift registers in LEs. You can add pipeline registers to the DSP
block for accelerated operation. Registers are available at the input and
output of the multiplier, and at the output of the
adder/subtractor/accumulator or summation block.
DSP blocks have four modes of operation:
■
■
■
■
Simple multiplier mode
Multiply-accumulator mode
Two-multipliers adder mode
Four-multipliers adder mode
Associated megafunctions are available in the Quartus II software to
implement each mode of the DSP block.
DSP Block Megafunctions
You can use the lpm_mult megafunction to configure the DSP block for
simple multiplier mode. You can set the lpm_mult Multiplier
Implementation option in the MegaWizard Plug-In Manager to either
use the default implementation, ESBs, or the DSP blocks. If you select the
Use Default option, the compiler first attempts to place the multiplier in
the DSP blocks. However, under certain conditions, the compiler may
implement the multiplier in LEs. The placement depends on factors such
as DSP block resource consumption, the width of the multiplier, whether
an operand is a constant, and other options chosen for the megafunction.
Stratix and Stratix GX devices do not support the Use ESBs option. If you
select this option, the Quartus II software tries to place the multiplier in
unused DSP blocks.
You can recompile APEX II or APEX 20K designs using the lpm_mult
megafunction for Stratix and Stratix GX devices in the Quartus II
software without changing the megafunction. This makes converting
lpm_mult megafunction designs to Stratix or Stratix GX devices
straightforward.
10–16
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
APEX II and APEX 20K designs use pipeline stages to improve registered
performance of LE-based multipliers at the expense of latency. However,
you may not need to use pipeline stages when targeting Stratix and
Stratix GX high-speed DSP blocks. The DSP blocks offer three sets of
dedicated pipeline registers. Therefore, Altera recommends that you
reduce the number of pipeline stages to three or fewer and implement
them in the DSP blocks. Additional pipeline stages are implemented in
LEs, which add latency without providing any performance benefit.
For example, you can configure a DSP block for 36 × 36-bit multiplication
using the lpm_mult megafunction. If you specify two pipeline stages,
the software uses the DSP block input and pipeline registers. If you
specify three pipeline stages, the software places the third pipeline stage
in the DSP block output registers. This design yields the same
performance with three pipeline stages because the critical path for a
36 × 36-bit operation is within the multiplier. With four or more pipeline
stages, the device inefficiently uses LE resources for the additional
pipeline stages. Therefore, if multiplier modules in APEX II or APEX 20K
designs are converted to Stratix or Stratix GX designs and do not require
the same number of pipeline stages, the surrounding circuitry must be
modified to preserve the original functionality of the design.
A design with multipliers feeding an accumulator can use the
altmult_accum (MAC) megafunction to set the DSP block in multiplyaccumulator mode. If the APEX II or APEX 20K design already uses LEbased multipliers feeding an accumulator, the Quartus II software does
not automatically instantiate the new altmult_accum (MAC)
megafunction. Therefore, you should use the MegaWizard Plug-In
Manager to instantiate the altmult_accum (MAC) megafunction. You
can also use LeonardoSpectrum™ or Synplify synthesis tools, which have
DSP block inference support, to instantiate the megafunction.
Designs that use multipliers feeding into adders can instantiate the new
altmult_add megafunction to configure the DSP blocks for twomultipliers adder or four-multipliers adder mode. You can also use the
altmult_add megafunction for stand-alone multipliers to take
advantage of the DSP blocks features such as dynamic sign control of the
inputs and the input shift register connections. These features are not
accessible through the lpm_mult megafunction. If your APEX II or
APEX 20K designs already use multipliers feeding an adder/subtractor,
the Quartus II software does not automatically infer the new
altmult_add megafunction. Therefore, you should step through the
MegaWizard Plug-In Manager to instantiate the new altmult_add
megafunction or use LeonardoSpectrum or Synplify synthesis tools,
which have DSP block inference support.
Altera Corporation
July 2005
10–17
Stratix Device Handbook, Volume 2
PLLs & Clock Networks
Furthermore, the altmult_add and altmult_accum (MAC)
megafunctions are only available for Stratix and Stratix GX devices
because these megafunctions target Stratix and Stratix GX DSP blocks,
which are not available in other device families. If you attempt to use
these megafunctions in designs that target other Altera device families,
the Quartus II software reports an error message. Use lpm_mult and an
lpm_add_sub or an altaccumulate megafunction for similar
functionality in other device families.
If you use a third-party synthesis tool, you may be able to avoid the
megafunction conversion process. LeonardoSpectrum and Synplify
provide inference support for lpm_mult, altmult_add, and
altmult_accum (MAC) to use the DSP blocks.
If your design does not require you to implement all the multipliers in
DSP blocks, you must manually set a global parameter or a parameter for
each instance to force the tool to implement the lpm_mult megafunction
in LEs. Depending on the synthesis tools, inference of DSP blocks is
handled differently.
f
PLLs & Clock
Networks
For more information about using DSP blocks in Stratix and Stratix GX
devices, see the DSP Blocks in Stratix & Stratix GX Devices chapter of the
Stratix Device Handbook.
Stratix and Stratix GX devices provide exceptional clock management
with a hierarchical clock network and up to four enhanced phase-locked
loops (PLLs) and eight fast PLLs versus the four general-purpose PLLs
and four True-LVDSTM PLLs in APEX II devices. By providing superior
clock interfacing, numerous advanced clocking features, and significant
enhancements over APEX II and APEX 20K PLLs, the Stratix and
Stratix GX device PLLs increase system performance and bandwidth.
Clock Networks
There are 16 global clock networks available throughout each Stratix or
Stratix GX device as well as two fast regional and four regional clock
networks per device quadrant, resulting in up to 40 unique clock
networks per device. The increased number of dedicated clock resources
available in Stratix and Stratix GX devices eliminate the need to use
general-purpose I/O pins as clock inputs.
Stratix EP1S25 and smaller devices have 16 dedicated clock pins and
EP1S30 and larger devices have four additional clock pins to feed various
clocking networks. In comparison, APEX II devices have eight dedicated
clock pins and APEX 20KE and APEX 20KC devices have four dedicated
clock pins.
10–18
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
The dedicated clock pins in Stratix and Stratix GX devices can feed the
PLL clock inputs, the global clock networks, and the regional clock
networks. PLL outputs and internally-generated signals can also drive
the global clock network. These global clocks are available throughout
the entire device to clock all device resources.
Stratix and Stratix GX devices are divided into four quadrants, each
equipped with four regional clock networks. The regional clock network
can be fed by either the dedicated clock pins or the PLL outputs within its
device quadrant. The regional clock network can only feed device
resources within its particular device quadrant.
Each Stratix and Stratix GX device provides eight dedicated fast clock
I/O pins FCLK[7..0] versus four dedicated fast I/O pins in APEX II
and APEX 20K devices. The fast regional clock network can be fed by
these dedicated FCLK[7..0] pins or by the I/O interconnect. The I/O
interconnect allows internal logic or any I/O pin to drive the fast regional
clock network. The fast regional clock network is available for generalpurpose clocking as well as high fan-out control signals such as clear,
preset, enable, TRDY and IRDY for PCI applications, or bidirectional or
output pins.
EP1S25 and smaller devices have eight fast regional clock networks, two
per device quadrant. The quadrants in EP1S30 and larger devices are
divided in half, and each half-quadrant can be clocked by one of the eight
fast regional networks. Additionally, each fast regional clock network can
drive its neighboring half-quadrant (within the same device quadrant).
PLLs
Table 10–6 highlights Stratix and Stratix GX PLL enhancements to
existing APEX II, APEX 20KE and APEX 20KC PLL features.
Table 10–6. Stratix & Stratix GX PLL vs. APEX II, APEX 20KE & APEX 20KC PLL Features (Part 1 of 2)
Stratix & Stratix GX
Feature
APEX II PLLs
Enhanced PLLs
Fast PLLs
APEX 20KE &
APEX 20KC PLLs
Number of PLLs
Two (EP1S30 and
smaller devices);
four (EP1S40 and
larger devices) (9)
Four (EP1S25 and Four generalpurpose PLLs and
smaller devices);
four LVDS PLLs
eight (EP1S30
and larger
devices) (10)
Up to four generalpurpose PLLs. Up
to two LVDS PLLs.
(1)
Minimum input frequency
3 MHz
15 MHz
1.5 MHz
1.5 MHz
Maximum input frequency
250 to 582 MHz (2) 644.5 MHz (11)
420 MHz
420 MHz
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
PLLs & Clock Networks
Table 10–6. Stratix & Stratix GX PLL vs. APEX II, APEX 20KE & APEX 20KC PLL Features (Part 2 of 2)
Stratix & Stratix GX
Feature
APEX II PLLs
Enhanced PLLs
Fast PLLs
APEX 20KE &
APEX 20KC PLLs
Internal clock outputs per
PLL
6
3 (3)
2
2
External clock outputs per
PLL
Four
differential/eight
singled-ended or
one single-ended
(4)
Yes (5)
1
1
Phase Shift
Down to 160-ps
increments (6)
Down to 125-ps
increments (6)
500-ps to 1-ns
resolution
0.4- to 1-ns
resolution
Time shift
250-ps increments No
for ± 3 ns (7)
No
No
M counter values
1 to 512
1 to 32
1 to 160
2 to 160
N counter values
1 to 512
N/A
1 to 16
1 to 16
PLL clock input sharing
No
Yes
Yes
Yes
T1/E1 rate conversion (8)
No
No
Yes
Yes
Notes to Table 10–6:
(1)
EP20K200E and smaller devices only have two general-purpose PLLs. EP20K400E and larger devices have two
LVDS PLLs and four general-purpose PLLs. For more information, see AN 115: Using the ClockLock & ClockBoost
PLL Features in APEX Devices.
(2) The maximum input frequency for Stratix and Stratix GX enhanced PLLs depends on the I/O standard used with
that input clock pin. For more information, see the Stratix Device Family Data Sheet section of the Stratix Device
Handbook, Volume 1 or the Stratix GX Device Family Data Sheet section of the Stratix GX Device Handbook, Volume 1.
(3) Fast PLLs 1, 2, 3, and 4 have three internal clock output ports per PLL. Fast PLLs 7, 8, 9, and 10 have two internal
clock output ports per PLL.
(4) Every Stratix device has two enhanced PLLs with eight single-ended or four differential outputs each. Two
additional enhanced PLLs in EP1S80, EP1S60, and EP1S40 devices each have one single-ended output.
(5) Any I/O pin can be driven by the fast PLL global or regional outputs as an external clock output pin.
(6) The smallest phase shift unit is determined by the voltage-controlled oscillator (VCO) period divided by 8.
(7) There is a maximum of 3 ns between any two PLL clock outputs.
(8) The T1 clock frequency is 1.544 MHz and the E1 clock frequency is 2.048 MHz, which violates the minimum clock
input frequency requirement of the Stratix PLL.
(9) Stratix GX EP1SGX10 and EP1SGX25 contain two. EP1SGX40 contains four.
(10) Stratix GX EP1SGX10 and EP1SGX25 contain two. EP1SGX40 contains four.
(11) Stratix GX supports clock rates of 1 Gbps using DPA.
Enhanced PLLs
Stratix and Stratix GX devices provide up to four enhanced PLLs with
advanced PLL features. In addition to the feature changes mentioned in
Table 10–6, Stratix and Stratix GX device PLLs include many new,
10–20
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
advanced features to improve system timing management and
performance. Table 10–7 shows some of the new features available in
Stratix and Stratix GX enhanced PLLs.
Table 10–7. Stratix & Stratix GX Enhanced PLL Features
Feature
Description
Programmable duty cycle (1) Allows variable duty cycle for each PLL clock output.
PLL clock outputs can feed
logic array (1)
Allows the PLL clock outputs to feed data ports of registers or combinatorial logic.
PLL locked output can feed
the logic array (1)
Allows the PLL locked port to feed data ports of registers or combinatorial logic.
Multiplication allowed in
zero-delay buffer mode or
external feedback mode
The PLL clock outputs can be a multiplied or divided down ratio of the PLL input
clock.
Programmable phase shift
allowed in zero-delay buffer
mode or external feedback
mode (2)
The PLL clock outputs can be phase shifted. The phase shift is relative to the PLL
clock output.
Phase frequency detector
(PFD) disable
Allows the VCO to operate at its last set control voltage and frequency with some
long term drift.
Clock output disable (3)
PLL maintains lock with output clocks disabled. (4)
Programmable lock detect &
gated lock
Holds the lock signal low for a programmable number of input clock cycles.
Dynamic clock switchover
Enables the PLL to switch between two reference input clocks, either for clock
redundancy or dual-clock domain applications.
PLL reconfiguration
Allows the counters and delay elements within the PLL to be reconfigured in realtime without reloading a programmer object file (.pof).
Programmable bandwidth
Provides advanced control of the PLL bandwidth by using the programmable
control of the PLL loop characteristics.
Spread spectrum
Modulates the target frequency over a frequency range to reduce
electromagnetic interference (EMI) emissions.
Notes to Table 10–7:
(1)
(2)
(3)
(4)
These features are also available in fast PLLs.
In addition to the delay chains at each counter, you can specify the programmable phase shift for each PLL output
at fine and coarse levels.
Each PLL clock output has an associated clock enable signal.
If the PLL is used in external feedback mode, the PLL will need to relock.
Fast PLLs
Stratix and Stratix GX fast PLLs are similar to the APEX II True-LVDS
PLLs in that the W setting, which governs the relationship between the
clock input and the data rate, and the J setting, which controls the width
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
PLLs & Clock Networks
of the high-speed differential I/O data bus, do not have to be equal.
Additionally, Stratix and Stratix GX fast PLLs offer up to three clock
outputs, two multiplied high-speed PLL clocks to drive the
serializer/deserializer (SERDES) block and/or an external pin, and a
low-speed clock to drive the logic array. You can use fast PLLs for both
high-speed interfacing and for general-purpose PLL applications.
Table 10–8 shows the differences between Stratix and Stratix GX fast
PLLs and APEX II and APEX 20K True-LVDS PLLs.
Table 10–8. Stratix & Stratix GX Fast PLL vs. APEX II & APEX 20K True-LVDS PLL
Feature
Stratix & Stratix GX
APEX 20KE
APEX 20KC
APEX II
Number of fast PLLs or TrueLVDS PLLs (1)
Four (EP1S25 and smaller
devices) fast PLLs
Eight (EP1S30 and larger
devices) fast PLLs (4)
Four True-LVDS
PLLs
Two True-LVDS
PLLs (2)
Number of channels per
transmitter/receiver block
20
18
18
VCO frequency
300 to 840 MHz (5)
200 MHz to 1GHz
200 to 840 MHz
Minimum input frequency
M = 4, 5, 6
300 – M MHz
50 MHz
50 MHz
M = 4 (3)
Minimum input frequency
M = 7, 8, 9, 10
300 – M MHz
30 MHz
30 MHz
M = 7, 8 (3)
Notes to Table 10–8:
(1)
(2)
(3)
(4)
(5)
You can also use Stratix and Stratix GX device fast PLLs for general-purpose PLL applications.
EP20K400E and larger devices have two True-LVDS PLLs.
In APEX 20KE and APEX 20KC devices, M = 4, 7, or 8.
Stratix GX EP1SGX10 and EP1SGX25 contain two. EP1SGX10 contains four.
Stratix GX supports a frequency range of 300–1000 MHz (using DPA).
The Stratix and Stratix GX fast PLL VCO frequency range is 300 to 840
MHz, and the APEX II True-LVDS PLL VCO frequency range is 200 MHz
to 1 GHz. Therefore, you must update designs that use a data rate of less
than 300 megabits per second (Mbps) to use the enhanced PLLs and M512
RAM blocks in SERDES bypass mode. Additionally, you must update
designs that use a data rate faster than 840 Mbps.
altpll Megafunction
Altera recommends that you replace instances of the altclklock
megafunction with the altpll megafunction to take advantage of new
Stratix and Stratix GX PLL features. Although in most cases you can
retarget your APEX II or APEX 20K design to a Stratix or Stratix GX
10–22
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Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
device with the altclklock megafunction, there are specific cases
where you must use the altpll megafunction, as explained in this
section.
In the MegaWizard Plug-In Manager, select the altpll megafunction in
the I/O directory from the Available Megafunctions box (see
Figure 10–9). The altclklock megafunction is also available from the
Quartus II software for backward compatibility, but instantiates the new
altpll megafunction when targeting Stratix or Stratix GX devices. The
Quartus II Compiler automatically selects whether the altpll module
uses either an enhanced PLL or a fast PLL based on the design’s PLL
needs and the feature requirements of each PLL.
Figure 10–9. altpll Megafunction Selection in the MegaWizard Plug-In
Manager
You can compile APEX II, APEX 20KE, and APEX 20KC designs using the
altclklock megafunction in normal mode for Stratix and Stratix GX
devices without updating the megafunction. However, you should
replace the altclklock megafunction with the altpll megafunction.
If the Quartus II software cannot implement the requested clock
multiplication and division of the PLL, the compiler reports an error
message with the appropriate reason stated.
Altera Corporation
July 2005
10–23
Stratix Device Handbook, Volume 2
PLLs & Clock Networks
APEX II, APEX 20KE, and APEX 20KC devices have only one external
clock output available per PLL. Therefore, when retargeting an APEX II,
APEX 20KE, or APEX 20KC design that uses PLLs in zero delay buffer
mode or external feedback mode to a Stratix or Stratix GX device, you
should replace instances of the altclklock megafunction. If an
APEX II, APEX 20KE, or APEX 20KC altclklock module only uses one
PLL clock output (internal or external) and is compiled to target a Stratix
or Stratix GX device, the design compiles successfully with a warning
that the design uses the Stratix or Stratix GX PLL external clock output,
extclk0. However, if the APEX II, APEX 20KE, or APEX 20KC PLL has
more than one PLL clock output, you must replace instances of the
altclklock megafunction with the altpll megafunction because the
Quartus II Compiler does not know which PLL clock output is fed to an
external output pin or fed back to the Stratix or Stratix GX device fbin
pin. For example, if an APEX II, APEX 20KE, or APEX 20KC design with
an altclklock megafunction uses the clock0 output port to feed the
external clock output pin and the clock1 output port to feed the internal
logic array, the Quartus II software generates an error during
compilation and you must use the MegaWizard Plug-In Manager to
instantiate the altpll megafunction. By using the altpll
megafunction, you can choose which of the four external clock outputs to
use and take advantage of the new Stratix and Stratix GX PLL features
now available in the zero delay buffer mode or external feedback mode.
Timing Analysis
When the Quartus II software performs a timing analysis for APEX II,
APEX 20KE, or APEX 20KC designs, PLL clock settings override the
project clock settings. However, during timing analysis for Stratix and
Stratix GX designs using PLLs, the project clock settings override the PLL
input clock frequency and duty cycle settings. The MegaWizard Plug-In
Manager does not use the project clock settings to determine the altpll
parameters. This saves time with designs that use features such as clock
switchover or PLL reconfiguration because the Quartus II software can
perform a timing analysis without recompiling the design. It is important
to note the following:
■
■
■
■
A warning during compilation reports that the project clock settings
overrides the PLL clock settings.
The project clock setting overrides the PLL clock settings for timingdriven compilation.
The compiler will check the lock frequency range of the PLL. If the
frequency specified in the project clock settings is outside the lock
frequency range, the PLL clock settings will not be overridden.
Performing a timing analysis without recompiling your design does
not change the programming files. You must recompile your design
to update the programming files.
10–24
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
■
A Default Required fMAX setting does not override the PLL clock
settings. Only individual clock settings override the PLL clock
settings.
Therefore, you can enter different project clock settings corresponding to
new PLL settings and accelerate timing analysis by eliminating a full
compilation cycle.
f
I/O Structure
For more information about using Stratix and Stratix GX PLLs, see the
General-Purpose PLLs in Stratix & Stratix GX Devices chapter.
The Stratix and Stratix GX I/O element (IOE) architecture is similar to the
APEX II architecture, with a total of six registers and a latch in each IOE.
The registers are organized in three sets: two output registers to drive a
single or double-data rate (DDR) output path, two input registers and a
latch to support a single or DDR input path, and two output enable
registers to enhance clock-to-output enable timing or for DDR SDRAM
interfacing. A new synchronous reset signal is available to each of the
three sets of registers for preset or clear, or neither. In addition to the
advanced IOE architecture, the Stratix and Stratix GX IOE features
dedicated circuitry for external RAM interfacing, new I/O standards,
differential on-chip termination, and high-speed differential I/O
standard support.
External RAM Interfacing
The advanced Stratix and Stratix GX IOE architecture includes dedicated
circuitry to interface with external RAM. This circuitry provides
enhanced support for external high-speed memory devices such as DDR
SDRAM and FCRAM. The DDR SDRAM interface uses a bidirectional
signal, DQS, to clock data, DQ, at both the transmitting and receiving
device. Stratix and Stratix GX devices transmit the DQS signal with the DQ
data signals to minimize clock to data skew.
Stratix and Stratix GX devices include groups of programmable DQS and
DQ pins, in the top and bottom I/O banks of the device. Each group
consists of a DQS pin that supports a fixed number of DQ pins. The number
of DQ pins depends on the DQ bus mode. When using the external RAM
interfacing circuitry, the DQS pin drives a dedicated clock network that
feeds the DQ pins residing in that bank. The Stratix and Stratix GX IOE has
programmable delay chains that can phase shift the DQS signal by 90° or
72° to ensure data is sampled at the appropriate point in time. Therefore,
the Stratix and Stratix GX devices make full use of the IOEs, and remove
the need to build the input data path in the logic array. You can make
these I/O assignments in the Quartus II Assignment Organizer.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
I/O Structure
f
For more information on external RAM interfacing, see the Stratix Device
Family Data Sheet section of the Stratix Device Handbook, Volume 1 or the
Stratix GX Device Family Data Sheet in the Stratix GX Device Family
Handbook, Volume 1.
I/O Standard Support
The Stratix and Stratix GX devices support all of the I/O standards that
APEX II and APEX 20K devices support, including high-speed
differential I/O standards such as LVDS, LVPECL, PCML, and
HyperTransportTM technology, differential HSTL on input and output
clocks, and differential SSTL on output clocks. Stratix and Stratix GX
devices also introduce support for SSTL-18 Class I & II. Similar to APEX II
devices, Stratix and Stratix GX devices only support certain I/O
standards in designated I/O banks. In addition, vref pins are dedicated
pins in Stratix and Stratix GX devices and now support up to 40 input
pins.
f
For more information about I/O standard support in Stratix and
Stratix GX devices, see the Selectable I/O Standards in Stratix &
Stratix GX Devices chapter.
High-Speed Differential I/O Standards
Stratix and Stratix GX devices support high-speed differential interfaces
at speeds up to 840 Mbps using high-speed PLLs that drive a dedicated
clock network to the SERDES. Each fast PLL can drive up to 20 highspeed channels. Stratix and Stratix GX devices use enhanced PLLs and
M512 RAM blocks to provide up to 420 Mbps performance for SERDES
bypass clock interfacing. There is no restriction on the number of
channels that can be clocked using this scenario.
Stratix and Stratix GX devices have a different number of differential
channels than APEX II devices. Tables 10–9 and 10–10 highlight the
number of differential channels supported in Stratix and Stratix GX
devices.
Table 10–9. Number of Dedicated DIfferential Channels in Stratix Devices
(Part 1 of 2) Note (1)
Device
EP1S10
10–26
Stratix Device Handbook, Volume 2
Pin Count
Number of Receiver
Channels
Number of
Transmitter Channels
672
36
36
780
44
44
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
Table 10–9. Number of Dedicated DIfferential Channels in Stratix Devices
(Part 2 of 2) Note (1)
Device
EP1S20
EP1S25
EP1S30
EP1S40
Pin Count
Number of Receiver
Channels
Number of
Transmitter Channels
672
50
48
780
66
66
672
58
56
780
66
70
1,020
78
78
780
66
70
956
80
80
1,020
80
80
2
2
956
80
80
1,020
1,508
EP1S60
EP1S80
80
80
10
10
80
80
10
10
956
80
80
1,020
80
80
10
12
1,508
80
80
36
36
956
80
80
0
40
1,508
80
80
56
72
Note to Table 10–9:
(1)
Altera Corporation
July 2005
For information on channel speeds, see the Stratix Device Family Data Sheet section
of the Stratix Device Handbook, Volume 1 and the High-Speed Differential I/O
Interfaces chapter in the Stratix Device Handbook, Volume 2.
10–27
Stratix Device Handbook, Volume 2
I/O Structure
Table 10–10. Number of Dedicated DIfferential Channels in Stratix GX
Devices Note (1)
Pin Count
Number of
Transceivers
Number of SourceSynchronous
Channels
EP1SGX10 C
672
4
22
EP1SGX10 D
672
8
22
EP1SGX25 C
672
4
39
EP1SGX25 D
672/1,020
8
39
EP1SGX25 F
1,020
16
39
EP1SGX40 D
1,020
8
45
EP1SGX40 G
1,020
20
45
Device
Note to Table 10–10:
(1)
For information on channel speeds, see the Stratix GX Device Family Data Sheet
section of the Stratix GX Device Handbook, Volume 1 and the High-Speed
Source-Synchronous Differential I/O Interfaces in Stratix GX Devices chapter of the
Stratix GX Device Handbook, Volume 2.
The differential I/O within Stratix GX also provides dynamic phase
alignment (DPA). DPA enables the differential I/O to operate up to
1 Gbps per channel. DPA automatically and continuously tracks
fluctuations caused by system variations and self-adjusts to eliminate the
phase skew between the multiplied clock and the serial data. The block
contains a dynamic phase selector for phase detection and selection, a
SERDES, a synchronizer, and a data realigner circuit. You can bypass the
dynamic phase aligner without affecting the basic source-synchronous
operation of the channel by using a separate deserializer.
If you compile an APEX II LVDS design that uses clock-data
synchronization (CDS) for a Stratix or Stratix GX device, the Quartus II
software issues a warning during compilation that Stratix and Stratix GX
devices do not support CDS.
Stratix and Stratix GX devices offer a flexible solution using new byte
realignment circuitry to correct for byte misalignment by shifting, or
slipping, data bits. Stratix and Stratix GX devices activate the byte
realignment circuitry when an external pin (rx_data_align) or an
internal custom-made state machine asserts the SYNC node high.
APEX II, APEX 20KE, and APEX 20KCdevices have a dedicated
transmitter clock output pin (LVDSTXOUTCLK). In Stratix and Stratix GX
devices, a transmitter dataout channel with an LVDS clock (fast clock)
generates the transmitter clock output. Therefore, you can drive any
10–28
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
channel as an output clock to an I/O pin, not just dedicated clock output
pins. This solution offers better versatility to address various applications
that require more complex clocking schemes.
f
For more information on differential I/O support, data realignment, and
the transmitter clock output in Stratix and Stratix GX devices, see the
High-Speed Differential I/O Interfaces in Stratix Devices chapter.
altlvds Megafunction
To take full advantage of the high-speed differential I/O standards
available in Stratix and Stratix GX devices, you should update each
instance of the altlvds megafunction in APEX II, APEX 20KE, and
APEX 20KC designs. In the MegaWizard Plug-In Manager, choose the
altlvds megafunction, select Stratix or Stratix GX as the target device
family, update the megafunction, and recompile your design.
The altlvds megafunction supports new Stratix and Stratix GX
parameters that are not available for APEX II, APEX 20KE, and
APEX 20KC devices. Tables 10–11 and 10–12 describe the new
parameters for the LVDS receiver and LVDS transmitter, respectively.
Table 10–11. New altlvds Parameters for Stratix LVDS Receiver Note (1)
Parameter
Function
input_data_rate (2)
Specifies the data rate in Mbps. This parameter replaces the
multiplication factor W.
inclock_data_alignment
Indicates the alignment of rx_inclk and rx_in data.
rx_data_align
Drives the data alignment port of the fast PLL and enables byte
realignment circuitry.
registered_data_align_input Registers the rx_data_align input port to be clocked by
rx_outclock.
common_rx_tx_pll (3)
Indicates the fast PLL can be shared between receiver and transmitter
applications.
Table 10–12. New altlvds Parameters for Stratix LVDS Transmitter (Part 1 of 2) Note (1)
Parameter
Function
output_data_rate (2)
Specifies the data rate in Mbps. This parameter replaces the
multiplication factor W.
inclock_data_alignment
Indicates the alignment of tx_inclk and tx_in data.
outclock_alignment
Specifies the alignment of tx_outclock and tx_out data.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration
Table 10–12. New altlvds Parameters for Stratix LVDS Transmitter (Part 2 of 2) Note (1)
Parameter
Function
registered_input
Specifies the clock source for the input synchronization registers,
which can be either tx_inclock or tx_coreclock. Used only
when the Registered Inputs option is selected.
common_rx_tx_pll (3)
Indicates the fast PLL can be shared between receiver and transmitter
applications.
Notes to Tables 10–11 and 10–12:
(1)
(2)
(3)
You can specify these parameters in the MegaWizard Plug-In Manager.
You must specify a data rate in the MegaWizard Plug-In Manager instead of a W factor.
The same fast PLL can be used to clock both the receiver and transmitter only if both are running at the same
frequency.
Above the standard I/O offered by APEX II, APEX 20K, and Stratix
devices, Stratix GX devices provide up to 20 3.175 Gbps transceivers. The
transceivers provide high-speed serial links for chip-to-chip, backplane,
and line-side connectivity and support a number of the emerging
high-speed protocols. You can find more information in the Stratix GX
Family Data Sheet in the Stratix GX Family Handbook, Volume 1.
Configuration
The Stratix and Stratix GX devices supports all current configuration
schemes, including the use of enhanced configuration devices, passive
serial (PS), passive parallel asynchronous (PPA), fast passive parallel
(FPP), and JTAG. Stratix and Stratix GX devices also provide a number of
new configuration enhancements that you can take advantage of when
migrating APEX II and APEX 20K designs to Stratix and Stratix GX
devices.
Configuration Speed & Schemes
You can configure Stratix and Stratix GX devices at a maximum clock
speed of 100 MHz, which is faster than the 66-MHz and 33-MHz
maximum configuration speeds for APEX II and APEX 20K devices,
respectively. Similar to APEX II devices, you can use 8-bit parallel data to
configure Stratix and Stratix GX devices (the target device can receive
byte-wide configuration data on each clock cycle) significantly speeding
up configuration times.
You can select a configuration scheme based on how the MSEL pins are
driven. Stratix and Stratix GX devices have three MSEL pins (APEX II and
APEX 20K devices have two MSEL pins) for determining the
configuration scheme.
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July 2005
Transitioning APEX Designs to Stratix & Stratix GX Devices
f
For more information about Stratix and Stratix GX configuration
schemes, see the Configuring Stratix & Stratix GX Devices chapter.
Remote Update Configuration
The APEX 20K device family introduced the concept of remote update
configuration, where you could send the APEX 20K device new
configuration files from a remote source and the device would store the
files in flash memory and reconfigure itself with the new configuration
data. The Stratix and Stratix GX devices enhance support for remote
update configuration with new, dedicated circuitry to handle and recover
from errors. If an error occurs either during device configuration or in
user mode, this new circuitry reconfigures the Stratix or Stratix GX device
to a known state. Additionally, the Stratix and Stratix GX devices have a
user watchdog timer to ensure the application configuration data
executes successfully during user mode. User logic must continually reset
this watchdog timer in order to validate that the application
configuration data is functioning properly.
f
For more information about how to use the remote and local update
modes, see the Remote System Configuration with Stratix & Stratix GX
Devices chapter.
JTAG Instruction Support
Stratix and Stratix GX devices support two new JTAG instructions,
PULSE_NCONFIG and CONFIG_IO. The PULSE_NCONFIG instruction
emulates pulsing the nCONFIG signal low to trigger reconfiguration,
while the actual nCONFIG pin on the device is unaffected. The
CONFIG_IO instruction allows you to use the JTAG chain to configure
I/O standards for all pins. Because this instruction interrupts device
configuration, you should reconfigure the Stratix or Stratix GX device
after you finish JTAG testing to ensure proper device operation.
Table 10–13 compares JTAG instruction support in Stratix and Stratix GX
devices versus APEX II and APEX 20K devices. For further information
about the supported JTAG instructions, see the appropriate device family
data sheet.
Table 10–13. JTAG Instruction Support (Part 1 of 2)
JTAG Instruction
Altera Corporation
July 2005
Stratix
APEX II
APEX 20K
SAMPLE/PRELOAD
v
v
v
EXTEST
v
v
v
BYPASS
v
v
v
USERCODE
v
v
v
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Stratix Device Handbook, Volume 2
Conclusion
Table 10–13. JTAG Instruction Support (Part 2 of 2)
JTAG Instruction
IDCODE
Conclusion
Stratix
APEX II
APEX 20K
v
v
v
ICR Instructions
v
v
v
SignalTapTM II Instructions
v
v
v
HIGHZ
v
v
CLAMP
v
v
PULSE_NCONFIG
v
CONFIG_IO
v
The Stratix and Stratix GX devices extend the advanced features available
in the APEX II and APEX 20K device families to deliver a complete
system-on-a-programmable-chip (SOPC) solution. By following these
guidelines, you can easily transition current APEX II and APEX 20K
designs to take advantage of the new features available in Stratix and
Stratix GX devices.
10–32
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Section VI. System
Configuration & Upgrades
This section describes configuration and remote system upgrade. This
section also provides configuration information for all of the supported
configuration schemes for Stratix® devices. These configuration schemes
use either a microprocessor, configuration device, or download cable.
There is detailed information on how to design with Altera® enhanced
configuration devices which includes information on how to manage
multiple configuration files and access the on-chip FLASH memory
space. The last chapter shows you how to perform remote and local
upgrades for your designs.
This section contains the following chapters:
f
Altera Corporation
■
Chapter 11, Configuring Stratix & Stratix GX Devices
■
Chapter 12, Remote System Configuration with Stratix & Stratix GX
Devices
For information on Altera enhanced configuration devices, see the
Enhanced Configuration Devices (EPC4, EPC8 & EPC16) Data Sheet chapter
in the Configuration Handbook, Volume 2.
Section VI–1
System Configuration & Upgrades
Revision History
Stratix Device Handbook, Volume 2
The table below shows the revision history for Chapters 11 through 12.
Chapter
Date/Version
11
July 2005, v3.2
Changes Made
●
Updated “PORSEL Pins” and “nIO_PULLUP Pins” sections.
Updated “FPP Configuration Using an Enhanced Configuration
Device” section.
Updated “PPA Configuration” section.
September 2004, v3.1
●
Corrected spelling error.
April 2004, v3.0
●
In the “PORSEL Pins” section and the “nIO_PULLUP Pins” section,
several pull-down resistors were changed to pull-up resistors.
Updated notes in Figure 11–3.
Two vertical VCC lines removed in Figures 11–12 to 11–14.
Three paragraphs added regarding the CONF_DONE and
INIT_DONE pins on page 13-18.
Value in Note 1 changed in Tables 11–8 and 11–9.
Deleted reference to AS in Table 11–15 because Stratix does not
support AS mode.
Text added before callout of Figure 11–7.
●
●
●
●
●
●
●
●
●
Updated Remote/local update PPA typical use description on page
11-1.
Updated VCCSEL Pins section on page 11-3.
Updated figures to use 10k resistors throughout for configuration
control signals.
Updated text on page 11-23 to tell how to connect a microprocessor
to nSTATUS.
Figure 11–19, Note 3.
Updated Table 11–12.
Added Note 6 to Figure 11–21 and the text below the figure describing
the nCE pin.
Updated definitions for CLKUSR, and JTAG pins in Table 11–16.
September 2004, v3.1
●
Editorial corrections.
April 2004, v3.0
●
The input file in Figure 12–22 was changed to
remote_update_initial_pgm.pdf.
Title in Figure 12–23 was changed from Local... to Remote Update
Partial Programming File Generation.
Rearranged the “Quartus II Software Support” section.
July 2003, v2.0
●
●
●
●
●
●
●
12
●
●
July 2003, v2.0
Section VI–2
●
Added altremote_update Megafunction section on pages 12-18 to 1221.
Altera Corporation
11. Configuring Stratix &
Stratix GX Devices
S52013-3.2
Introduction
You can configure Stratix® and Stratix GX devices using one of several
configuration schemes. All configuration schemes use either a
microprocessor, configuration device, or a download cable. See
Table 11–1.
Table 11–1. Stratix & Stratix GX Device Configuration Schemes
Configuration Scheme
Typical Use
Fast passive parallel (FPP)
Configuration with a parallel synchronous configuration device or microprocessor
interface where eight bits of configuration data are loaded on every clock cycle.
Passive serial (PS)
Configuration with a serial synchronous microprocessor interface or the
MasterBlasterTM communications cable, USB Blaster, ByteBlasterTM II, or
ByteBlasterMV parallel port download cable.
Passive parallel
asynchronous (PPA)
Configuration with a parallel asynchronous microprocessor interface. In this
scheme, the microprocessor treats the target device as memory.
Remote/local update FPP
Configuration using a NiosTM (16-bit ISA) and Nios® II (32-bit ISA) or other
embedded processor. Allows you to update the Stratix or Stratix GX device
configuration remotely using the FPP scheme to load data.
Remote/local update PS
Passive serial synchronous configuration using a Nios or other embedded
processor. Allows you to update the Stratix or Stratix GX device configuration
remotely using the PS scheme to load data.
Remote/local update PPA
Passive parallel asynchronous configuration using a Nios or other embedded
processor. In this scheme, the Nios microprocessor treats the target device as
memory. Allows you to update the Stratix or Stratix GX device configuration
remotely using the PPA scheme to load data.
Joint Test Action Group
(JTAG)
Configuration through the IEEE Std. 1149.1 JTAG pins. You can perform JTAG
configuration with either a download cable or an embedded device. Ability to use
SignalTap® II Embedded Logic Analyzer.
This chapter discusses how to configure one or more Stratix or Stratix GX
devices. It should be used together with the following documents:
■
■
■
■
■
■
Altera Corporation
July 2005
MasterBlaster Serial/USB Communications Cable Data Sheet
USB Blaster USB Port Download Cable Development Tools Data Sheet
ByteBlaster II Parallel Port Download Cable Data Sheet
ByteBlasterMV Parallel Port Download Cable Data Sheets
Configuration Devices for SRAM-Based LUT Devices Data Sheet
Enhanced Configuration Devices (EPC4, EPC8, & EPC16) Data Sheet
11–1
Device Configuration Overview
■
f
Device
Configuration
Overview
The Remote System Configuration with Stratix & Stratix GX Devices
chapter
For more information on setting device configuration options or
generating configuration files, see the Software Setting chapter in
Volume 2 of the Configuration Handbook.
During device operation, the FPGA stores configuration data in SRAM
cells. Because SRAM memory is volatile, you must load the SRAM cells
with the configuration data each time the device powers up. After
configuration, the device must initialize its registers and I/O pins. After
initialization, the device enters user mode. Figure 11–1 shows the state of
the device during the configuration, initialization, and user mode.
Figure 11–1. Stratix & Stratix GX Configuration Cycle
D(N – 1)
nCONFIG
nSTATUS
CONF_DONE (1)
(4)
DCLK
DATA High-Z
User I/O Pins (2)
D0
D1
D2
D3
DN
High-Z
High-Z
(5)
User I/O
INIT_DONE (3)
MODE
Configuration
Configuration
Initialization
User
Notes to Figure 11–1:
(1)
(2)
(3)
(4)
(5)
During initial power up and configuration, CONF_DONE is low. After configuration, CONF_DONE goes high. If the
device is reconfigured, CONF_DONE goes low after nCONFIG is driven low.
User I/O pins are tri-stated during configuration. Stratix and Stratix GX devices also have a weak pull-up resistor
on I/O pins during configuration that are enabled by nIO_PULLUP. After initialization, the user I/O pins perform
the function assigned in the user’s design.
If the INIT_DONE pin is used, it will be high because of an external 10 kΩ resistor pull-up when nCONFIG is low
and during the beginning of configuration. Once the option bit to enable INIT_DONE is programmed into the device
(during the first frame of configuration data), the INIT_DONE pin will go low.
DCLK should not be left floating. It should be driven high or low.
DATA0 should not be left floating. It should be driven high or low.
You can load the configuration data for the Stratix or Stratix GX device
using a passive configuration scheme. When using any passive
configuration scheme, the Stratix or Stratix GX device is incorporated into
a system with an intelligent host, such as a microprocessor, that controls
the configuration process. The host supplies configuration data from a
storage device (e.g., a hard disk, RAM, or other system memory). When
using passive configuration, you can change the target device’s
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Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
functionality while the system is in operation by reconfiguring the device.
You can also perform in-field upgrades by distributing a new
programming file to system users.
The following sections describe the MSEL[2..0], VCCSEL, PORSEL, and
nIO_PULLUP pins used in Stratix and Stratix GX device configuration.
MSEL[2..0] Pins
You can select a Stratix or Stratix GX device configuration scheme by
driving its MSEL2, MSEL1, and MSEL0 pins either high or low, as shown
in Table 11–2.
Table 11–2. Stratix & Stratix GX Device Configuration Schemes
Description
MSEL2
MSEL1
MSEL0
FPP configuration
0
0
0
PPA configuration
0
0
1
PS configuration
0
1
0
Remote/local update FPP (1)
1
0
0
Remote/local update PPA (1)
1
0
1
Remote/local update PS (1)
1
1
0
JTAG-based configuration (3)
(2)
(2)
(2)
Notes to Table 11–2:
(1)
(2)
(3)
These schemes require that you drive a secondary pin RUnLU to specify whether
to perform a remote update or local update.
Do not leave MSEL pins floating. Connect them to VC C I O or GND. These pins
support the non-JTAG configuration scheme used in production. If only JTAG
configuration is used you should connect the MSEL pins to ground.
JTAG-based configuration takes precedence over other configuration schemes,
which means the MSEL pins are ignored.
The MSEL[] pins can be tied to VCCIO of the I/O bank they reside in or
ground.
VCCSEL Pins
You can configure Stratix and Stratix GX devices using the 3.3-, 2.5-, 1.8-,
or 1.5-V LVTTL I/O standard on configuration and JTAG input pins.
VCCSEL is a dedicated input on Stratix and Stratix GX devices that selects
between 3.3-V/2.5-V input buffers and 1.8-V/1.5-V input buffers for
dedicated configuration input pins. A logic low supports 3.3-V/2.5-V
signaling, and a logic high supports 1.8-V/1.5-V signaling. A logic high
can also support 3.3-V/2.5-V signaling. VCCSEL affects the configuration
Altera Corporation
July 2005
11–3
Stratix Device Handbook, Volume 2
Device Configuration Overview
related I/O banks (3, 4, 7, and 8) where the following pins reside: TDI,
TMS, TCK, TRST, MSEL0, MSEL1, MSEL2, nCONFIG, nCE, DCLK, PLL_ENA,
CONF_DONE, nSTATUS. The VCCSEL pin can be pulled to 1.5, 1.8, 2.5, or
3.3-V for a logic high level. There is an internal 2.5-kΩ pull-down resistor
on VCCSEL. Therefore, if you are using a pull-up resister to pull up this
signal, you need to use a 1-kΩ resistor.
VCCSEL also sets the power-on-reset (POR) trip point for all the
configuration related I/O banks (3, 4, 7, and 8), ensuring that these I/O
banks have powered up to the appropriate voltage levels before
configuration begins. Upon power-up, the FPGA does not release
nSTATUS until VCCINT and all of the VCCIOs of the configuration I/O
banks are above their POR trip points. If you set VCCSEL to ground (logic
low), this sets the POR trip point for all configuration I/O banks to a
voltage consistent with 3.3-V/2.5-V signaling. When VCCSEL = 0, the
POR trip point for these I/O banks may be as high as 1.8 V. If VCCIO of any
of the configuration banks is set to 1.8 or 1.5 V, the voltage supplied to this
I/O bank(s) may never reach the POR trip point, which will not allow the
FPGA to begin configuration.
1
If the VCCIO of I/O banks 3, 4, 7, or 8 is set to 1.5 or 1.8 V and the
configuration signals used require 3.3-V or 2.5-V signaling you
should set VCCSEL to VCC (logic high) in order to lower the POR
trip point to enable successful configuration.
Table 11–3 shows how you should set the VCCSEL depending on the
VCCIO setting of the configuration I/O banks and your configuration
input signaling voltages.
Table 11–3. VCCSEL Setting
VCCIO (banks 3,4,7,8)
Configuration Input
Signaling Voltage
VCCSEL
3.3-V/2.5-V
3.3-V/2.5-V
GND
1.8-V/1.5-V
3.3-V/2.5-V/1.8-V/1.5-V
VCC
3.3-V/2.5-V
1.8-V/1.5-V
Not Supported
The VCCSEL signal does not control any of the dual-purpose pins,
including the dual-purpose configuration pins, such as the DATA[7..0]
and PPA pins (nWS, nRS, CS, nCS, and RDYnBSY). During configuration,
these dual-purpose pins drive out voltage levels corresponding to the
VCCIO supply voltage that powers the I/O bank containing the pin. After
configuration, the dual-purpose pins inherit the I/O standards specified
in the design.
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July 2005
Configuring Stratix & Stratix GX Devices
PORSEL Pins
PORSEL is a dedicated input pin used to select POR delay times of 2 ms
or 100 ms during power-up. When the PORSEL pin is connected to
ground, the POR time is 100 ms; when the PORSEL pin is connected to
VCC, the POR time is 2 ms. There is an internal 2.5-kΩ pull-down resistor
on PORSEL. Therefore if you are using a pull-up resistor to pull up this
signal, you need to use a 1-kΩ resistor.
When using enhanced configuration devices to configure Stratix devices,
make sure that the PORSEL setting of the Stratix device is the same or
faster than the PORSEL setting of the enhanced configuration device. If
the FPGA is not powered up after the enhanced configuration device exits
POR, the CONF_DONE signal will be high since the pull-up resistor is
pulling this signal high. When the enhanced configuration device exits
POR, OE of the enhanced configuration device is released and pulled
high by a pull-up resistor. Since the enhanced configuration device sees
its nCS/CONF_DONE signal also high, it enters a test mode. Therefore, you
must ensure the FPGA powers up before the enhanced configuration
device exits POR.
For more margin, the 100-ms setting can be selected when using an
enhanced configuration device to allow the Stratix FPGA to power-up
before configuration is attempted (see Table 11–4).
Table 11–4. PORSEL Settings
PORSEL Settings
POR Time (ms)
GND
100
VCC
2
nIO_PULLUP Pins
The nIO_PULLUP pin enables a built-in weak pull-up resistor to pull all
user I/O pins to VCCIO before and during device configuration. If
nIO_PULLUP is connected to VCC during configuration, the weak pullups on all user I/O pins and all dual-purpose pins are disabled. If
connected to ground, the pull-ups are enabled during configuration. The
nIO_PULLUP pin can be pulled to 1.5, 1.8, 2.5, or 3.3-V for a logic level
high. There is an internal 2.5-kΩ pull-down resistor on nIO_PULLUP.
Therefore, if you are using a pull-up resistor to pull up this signal, you
need to use a 1-kΩ resistor.
Altera Corporation
July 2005
11–5
Stratix Device Handbook, Volume 2
Configuration File Size
TDO & nCEO Pins
TDO and nCEO pins drive out the same voltage levels as the VCCIO that
powers the I/O bank where the pin resides. You must select the VCCIO
supply for the bank containing TDO accordingly. For example, when
using the ByteBlasterMV cable, the VCCIO for the bank containing TDO
must be powered up at 3.3-V. The current strength for TDO is 12 mA.
Configuration
File Size
Tables 11–5 and 11–6 summarize the approximate configuration file size
required for each Stratix and Stratix GX device. To calculate the amount
of storage space required for multi-device configurations, add the file size
of each device together.
Table 11–5. Stratix Configuration File Sizes
Device
Raw Binary File (.rbf) Size (Bits)
EP1S10
3,534,640
EP1S20
5,904,832
EP1S25
7,894,144
EP1S30
10,379,368
EP1S40
12,389,632
EP1S60
17,543,968
EP1S80
23,834,032
Table 11–6. Stratix GX Configuration File Sizes
Device
Raw Binary File Size (Bits)
EP1SGX10C
3,579,928
EP1SGX10D
3,579,928
EP1SGX25C
7,951,248
EP1SGX25D
7,951,248
EP1SGX25F
7,951,248
EP1SGX40D
12,531,440
EP1SGX40G
12,531,440
You should only use the numbers in Tables 11–5 and 11–6 to estimate the
file size before design compilation. The exact file size may vary because
different Altera® Quartus® II software versions may add a slightly
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July 2005
Configuring Stratix & Stratix GX Devices
different number of padding bits during programming. However, for any
specific version of the Quartus II software, any design targeted for the
same device has the same configuration file size.
Altera
Configuration
Devices
f
The Altera enhanced configuration devices (EPC16, EPC8, and EPC4
devices) support a single-device configuration solution for high-density
FPGAs and can be used in the FPP and PS configuration schemes. They
are ISP-capable through its JTAG interface. The enhanced configuration
devices are divided into two major blocks, the controller and the flash
memory.
For information on enhanced configuration devices, see the Enhanced
Configuration Devices (EPC4, EPC8 & EPC16) Data Sheet and the Using
Altera Enhanced Configuration Devices chapter in the Configuration
Handbook.
The EPC2 and EPC1 configuration devices provide configuration support
for the PS configuration scheme. The EPC2 device is ISP-capable through
its JTAG interface. The EPC2 and EPC1 can be cascaded to hold large
configuration files.
f
Configuration
Schemes
For more information on EPC2, EPC1, and EPC1441 configuration
devices, see the Configuration Devices for SRAM-Based LUT Devices Data
Sheet.
This section describes how to configure Stratix and Stratix GX devices
with the following configuration schemes:
■
■
■
■
■
■
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PS Configuration with Configuration Devices
PS Configuration with a Download Cable
PS Configuration with a Microprocessor
FPP Configuration
PPA Configuration
JTAG Programming & Configuration
JTAG Programming & Configuration of Multiple Devices
PS Configuration
PS configuration of Stratix and Stratix GX devices can be performed using
an intelligent host, such as a MAX® device, microprocessor with flash
memory, an Altera configuration device, or a download cable. In the PS
scheme, an external host (MAX device, embedded processor,
configuration device, or host PC) controls configuration. Configuration
data is clocked into the target Stratix devices via the DATA0 pin at each
rising edge of DCLK.
Altera Corporation
July 2005
11–7
Stratix Device Handbook, Volume 2
Configuration Schemes
PS Configuration with Configuration Devices
The configuration device scheme uses an Altera configuration device to
supply data to the Stratix or Stratix GX device in a serial bitstream (see
Figure 11–3).
In the configuration device scheme, nCONFIG is usually tied to VCC
(when using EPC16, EPC8, EPC4, or EPC2 devices, nCONFIG may be
connected to nINIT_CONF). Upon device power-up, the target Stratix or
Stratix GX device senses the low-to-high transition on nCONFIG and
initiates configuration. The target device then drives the open-drain
CONF_DONE pin low, which in-turn drives the configuration device’s nCS
pin low. When exiting power-on reset (POR), both the target and
configuration device release the open-drain nSTATUS pin.
Before configuration begins, the configuration device goes through a POR
delay of up to 200 ms to allow the power supply to stabilize (power the
Stratix or Stratix GX device before or during the POR time of the
configuration device). This POR delay has a maximum of 200 ms for
EPC2 devices. For enhanced configuration devices, you can select
between 2 ms and 100 ms by connecting PORSEL pin to VCC or GND,
accordingly. During this time, the configuration device drives its OE pin
low. This low signal delays configuration because the OE pin is connected
to the target device’s nSTATUS pin. When the target and configuration
devices complete POR, they release nSTATUS, which is then pulled high
by a pull-up resistor.
When configuring multiple devices, configuration does not begin until all
devices release their OE or nSTATUS pins. When all devices are ready, the
configuration device clocks data out serially to the target devices using an
internal oscillator.
After successful configuration, the Stratix FPGA starts initialization using
the 10-MHz internal oscillator as the reference clock. After initialization,
this internal oscillator is turned off. The CONF_DONE pin is released by the
target device and then pulled high by a pull-up resistor. When
initialization is complete, the FPGA enters user mode. The CONF_DONE
pin must have an external 10-kΩ pull-up resistor in order for the device
to initialize.
If an error occurs during configuration, the target device drives its
nSTATUS pin low, resetting itself internally and resetting the
configuration device. If the Auto-Restart Configuration on Frame Error
option—available in the Quartus II Global Device Options dialog box
(Assign menu)—is turned on, the device reconfigures automatically if an
error occurs. To find this option, choose Compiler Settings (Processing
menu), then click on the Chips & Devices tab.
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July 2005
Configuring Stratix & Stratix GX Devices
If this option is turned off, the external system must monitor nSTATUS for
errors and then pulse nCONFIG low to restart configuration. The external
system can pulse nCONFIG if it is under system control rather than tied to
VCC. When configuration is complete, the target device releases
CONF_DONE, which disables the configuration device by driving nCS
high. The configuration device drives DCLK low before and after
configuration.
In addition, if the configuration device sends all of its data and then
detects that CONF_DONE has not gone high, it recognizes that the target
device has not configured successfully. In this case, the configuration
device pulses its OE pin low for a few microseconds, driving the target
device’s nSTATUS pin low. If the Auto-Restart Configuration on Frame
Error option is set in the software, the target device resets and then pulses
its nSTATUS pin low. When nSTATUS returns high, the configuration
device reconfigures the target device. When configuration is complete,
the configuration device drives DCLK low.
Do not pull CONF_DONE low to delay initialization. Instead, use the
Quartus II software’s Enable User-Supplied Start-Up Clock (CLKUSR)
option to synchronize the initialization of multiple devices that are not in
the same configuration chain. Devices in the same configuration chain
initialize together. When CONF_DONE is driven low after device
configuration, the configuration device recognizes that the target device
has not configured successfully.
Figure 11–2 shows how to configure one Stratix or Stratix GX device with
one configuration device.
Altera Corporation
July 2005
11–9
Stratix Device Handbook, Volume 2
Configuration Schemes
Figure 11–2. Single Device Configuration Circuit
VCC (1)
10 kΩ
(2)
Stratix or Stratix GX Device
MSEL2
MSEL1
MSEL0
GND
nCEO
10 kΩ
(3)
VCC (1)
10 kΩ
(2)
Configuration
Device
DCLK
DATA
OE (2)
nCS (2)
nINIT_CONF (3)
DCLK
DATA0
nSTATUS
CONF_DONE
nCONFIG
VCC
VCC (1)
N.C.
nCE
GND
Notes to Figure 11–2:
(1)
(2)
(3)
The pull-up resistor should be connected to the same supply voltage as the
configuration device.
The enhanced configuration devices and EPC2 devices have internal
programmable pull-ups on OE and nCS. You should only use the internal pull-ups
of the configuration device if the nSTATUS and CONF_DONE signals are pulled up
to 3.3 V or 2.5 V (not 1.8 V or 1.5 V). If external pull-ups are used, they should be
10 kΩ.
The nINIT_CONF pin is available on EPC16, EPC8, EPC4, and EPC2 devices. If
nINIT_CONF is not used, nCONFIG must be pulled to VCC through a resistor. he
nINIT_CONF pin has an internal pull-up resistor that is always active in EPC16,
EPC8, EPC4, and EPC2 devices. These devices do not need an external pull-up
resistor on the nINIT_CONF pin.
Figure 11–3 shows how to configure multiple Stratix and Stratix GX
devices with multiple EPC2 or EPC1 configuration devices.
11–10
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July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–3. Multi-Device Configuration Circuit Note (1)
VCC (2) VCC (2) VCC (2)
10 kΩ 10 kΩ 10 kΩ
(3)
Stratix or Stratix GX Device 2
VCC
MSEL2
MSEL1
MSEL0
Stratix or Stratix GX Device 1
MSEL2
MSEL1
MSEL0
nCEO
nCE
nCEO
(3)
EPC1/EPC2
DCLK
DATA0
nSTATUS
CONF_DONE
nCONFIG
DCLK
DATA
OE (3)
nCS (3)
nCASC
nINIT_CONF (4)
GND
GND
N.C.
VCC
DCLK
DATA0
nSTATUS
CONF_DONE
nCONFIG
(4)
EPC1/EPC2
DCLK
DATA
nCS
OE
nINIT_CONF (4)
nCE
GND
Notes to Figure 11–3:
(1)
(2)
(3)
(4)
When performing multi-device active serial configuration, you must generate the configuration device programmer
object file (.pof) from each project’s SOF. You can combine multiple SOFs using the Quartus II software through the
Device & Pin Option dialog box. For more information on how to create configuration and programming files, see
the Software Settings section in the Configuration Handbook, Volume 2.
The pull-up resistor should be connected to the same supply voltage as the configuration device.
The enhanced configuration devices and EPC2 devices have internal programmable pull-ups on OE and nCS. You
should only use the internal pull-ups of the configuration device if the nSTATUS and CONF_DONE signals are pulled
up to 3.3 V or 2.5 V (not 1.8 V or 1.5 V). If external pull-ups are used, they should be 10 kΩ
The nINIT_CONF pin is available on EPC16, EPC8, EPC4, and EPC2 devices. If nINIT_CONF is not used, nCONFIG
must be pulled to VCC through a resistor. The nINIT_CONF pin has an internal pull-up resistor that is always active
in EPC16, EPC8, EPC4, and EPC2 devices. These devices do not need an external pull-up resistor on the
nINIT_CONF pin.
After the first Stratix or Stratix GX device completes configuration during
multi-device configuration, its nCEO pin activates the second device’s
nCE pin, prompting the second device to begin configuration. Because all
device CONF_DONE pins are tied together, all devices initialize and enter
user mode at the same time.
In addition, all nSTATUS pins are tied together; thus, if any device
(including the configuration devices) detects an error, configuration stops
for the entire chain. Also, if the first configuration device does not detect
CONF_DONE going high at the end of configuration, it resets the chain by
pulsing its OE pin low for a few microseconds. This low pulse drives the
OE pin low on the second configuration device and drives nSTATUS low
on all Stratix and Stratix GX devices, causing them to enter an error state.
If the Auto-Restart Configuration on Frame Error option is turned on in
the software, the Stratix or Stratix GX device releases its nSTATUS pins
after a reset time-out period. When the nSTATUS pins are released and
pulled high, the configuration devices reconfigure the chain. If the Auto-
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July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
Restart Configuration on Frame Error option is not turned on, the Stratix
or Stratix GX devices drive nSTATUS low until they are reset with a low
pulse on nCONFIG.
You can also cascade several EPC2/EPC1 configuration devices to
configure multiple Stratix and Stratix GX devices. When all data from the
first configuration device is sent, it drives nCASC low, which in turn
drives nCS on the subsequent configuration device. Because a
configuration device requires less than one clock cycle to activate a
subsequent configuration device, the data stream is uninterrupted.
1
You cannot cascade enhanced (EPC16, EPC8, and EPC4)
configuration devices.
You can use a single configuration chain to configure multiple Stratix and
Stratix GX devices. In this scheme, the nCEO pin of the first device is
connected to the nCE pin of the second device in the chain. If there are
additional devices, connect the nCE pin of the next device to the nCEO pin
of the previous device. To configure properly, all of the device
CONF_DONE and nSTATUS pins must be tied together.
Figure 11–4 shows an example of configuring multiple Stratix and Stratix
GX devices using a configuration device.
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July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–4. Configuring Multiple Stratix & Stratix GX Devices with A Single Configuration Device Note (1)
VCC (2)
VCC (2)
VCC (2)
10 kΩ
Stratix or Stratix GX Device 2
VCC
MSEL2
MSEL1
MSEL0
DCLK
DATA0
nSTATUS
CONF_DONE
nCONFIG
Configuration
Device (4)
Stratix or Stratix GX Device 1
MSEL2
MSEL1
MSEL0
10 kΩ
DCLK
DATA0
nSTATUS
CONF_DONE
nCONFIG
DCLK
DATA
OE
nCS
nCASC
nINIT_CONF (5)
GND
GND
N.C.
VCC
(3)
nCEO
nCE
nCEO
nCE
GND
Notes to Figure 11–4:
(1)
(2)
(3)
(4)
(5)
When performing multi-device active serial configuration, you must generate the configuration device programmer
object file (.pof) from each project’s SOF. You can combine multiple SOFs using the Quartus II software through the
Device & Pin Option dialog box. For more information on how to create configuration and programming files, see
the Software Settings section in the Configuration Handbook, Volume 2.
The pull-up resistor should be connected to the same supply voltage as the configuration device.
The enhanced configuration devices and EPC2 devices have internal programmable pull-ups on OE and nCS. You
should only use the internal pull-ups of the configuration device if the nSTATUS and CONF_DONE signals are pulled
up to 3.3 V or 2.5 V (not 1.8 V or 1.5 V). If external pull-ups are used, they should be 10 kΩ.
EPC16, EPC8, and EPC4 configuration devices cannot be cascaded.
The nINIT_CONF pin is available on EPC16, EPC8, EPC4, and EPC2 devices. If nINIT_CONF is not used, nCONFIG
must be pulled to VCC through a resistor. The nINIT_CONF pin has an internal pull-up resistor that is always active
in EPC16, EPC8, EPC4, and EPC2 devices. These devices do not need an external pull-up resistor on the
nINIT_CONF pin.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
Table 11–7 shows the status of the device DATA pins during and after
configuration.
Table 11–7. DATA Pin Status Before & After Configuration
Stratix or Stratix GX Device
Pins
During
After
DATA0 (1)
Used for configuration
DATA[7..1] (2)
Used in some configuration modes User defined
User defined
I/O Pins
Tri-state
User defined
Notes to Table 11–7:
(1)
(2)
The status shown is for configuration with a configuration device.
The function of these pins depends upon the settings specified in the Quartus II
software using the Device & Pin Option dialog box (see the Software Settings
section in the Configuration Handbook, Volume 2, and the Quartus II Help software
for more information).
PS Configuration with a Download Cable
In PS configuration with a download cable, an intelligent host transfers
data from a storage device to the Stratix or Stratix GX device through the
MasterBlaster, USB-Blaster, ByteBlaster II or ByteBlasterMV cable. To
initiate configuration in this scheme, the download cable generates a
low-to-high transition on the nCONFIG pin. The programming hardware
then places the configuration data one bit at a time on the device’s DATA0
pin. The data is clocked into the target device until CONF_DONE goes high.
The CONF_DONE pin must have an external 10-kΩ pull-up resistor in
order for the device to initialize.
When using programming hardware for the Stratix or Stratix GX device,
turning on the Auto-Restart Configuration on Frame Error option does
not affect the configuration cycle because the Quartus II software must
restart configuration when an error occurs. Additionally, the Enable
User-Supplied Start-Up Clock (CLKUSR) option has no affect on the
device initialization since this option is disabled in the SOF when
programming the FPGA using the Quartus II software programmer and
a download cable. Therefore, if you turn on the CLKUSR option, you do
not need to provide a clock on CLKUSR when you are configuring the
FPGA with the Quartus II programmer and a download cable.
Figure 11–5 shows PS configuration for the Stratix or Stratix GX device
using a MasterBlaster, USB-Blaster, ByteBLaster II or ByteBlasterMV
cable.
11–14
Stratix Device Handbook, Volume 2
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July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–5. PS Configuration Circuit with a Download Cable
VCC (1)
(2)
VCC (1)
10 kΩ
(2)
VCC
10 kΩ
MSEL2
VCC (1)
10 kΩ
Stratix or
Stratix GX Device
MSEL1
VCC (1)
10 kΩ
VCC (1)
10 kΩ
CONF_DONE
nSTATUS
MSEL0
(2)
nCE
nCEO
Download Cable
10-Pin Male Header
(PS Mode)
N.C.
GND
DCLK
DATA0
nCONFIG
Pin 1
VCC
GND
VIO (3)
Shield
GND
Notes to Figure 11–5:
(1)
(2)
(3)
You should connect the pull-up resistor to the same supply voltage as the MasterBlaster (VIO pin) or ByteBlasterMV
cable.
The pull-up resistors on the DATA0 and DCLK pins are only needed if the download cable is the only configuration
scheme used on the board. This is to ensure that the DATA0 and DCLK pins are not left floating after configuration.
For example, if the design also uses a configuration device, the pull-up resistors on the DATA0 and DCLK pins are
not necessary.
Pin 6 of the header is a VIO reference voltage for the MasterBlaster output driver. VIO should match the device’s
VCCIO. This pin is a no-connect pin for the ByteBlasterMV header.
You can use programming hardware to configure multiple Stratix and
Stratix GX devices by connecting each device’s nCEO pin to the
subsequent device’s nCE pin. All other configuration pins are connected
to each device in the chain.
Because all CONF_DONE pins are tied together, all devices in the chain
initialize and enter user mode at the same time. In addition, because the
nSTATUS pins are tied together, the entire chain halts configuration if any
device detects an error. In this situation, the Quartus II software must
restart configuration; the Auto-Restart Configuration on Frame Error
option does not affect the configuration cycle.
Figure 11–6 shows how to configure multiple Stratix and Stratix GX
devices with a MasterBlaster or ByteBlasterMV cable.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
Figure 11–6. Multi-Device PS Configuration with a Download Cable
VCC (1)
VCC
Stratix or
Stratix GX Device 1
VCC (1)
MSEL1
(2)
10 kΩ
CONF_DONE
nSTATUS
DCLK
MSEL0
10 kΩ
10 kΩ
Download Cable
10-Pin Male Header
(PS Mode)
VCC (1)
VCC (1)
(2)
10 kΩ
Pin 1
VCC
MSEL2
VCC (1)
GND
VIO (3)
nCE
10 kΩ
GND
DATA0
nCONFIG
VCC
nCEO
GND
Stratix or
Stratix GX Device 2
MSEL0
MSEL1
CONF_DONE
nSTATUS
DCLK
MSEL2
GND
nCE
nCEO
N.C.
DATA0
nCONFIG
Notes to Figure 11–6:
(1)
(2)
(3)
You should connect the pull-up resistor to the same supply voltage as the MasterBlaster (VIO pin) or ByteBlasterMV
cable.
The pull-up resistors on the DATA0 and DCLK pins are only needed if the download cable is the only configuration
scheme used on the board. This is to ensure that the DATA0 and DCLK pins are not left floating after configuration.
For example, if the design also uses a configuration device, the pull-up resistors on the DATA0 and DCLK pins are
not necessary.
VIO is a reference voltage for the MasterBlaster output driver. VIO should match the device’s VCCIO. See the
MasterBlaster Serial/USB Communications Cable Data Sheet for this value.
If you are using a download cable to configure device(s) on a board that
also has configuration devices, you should electrically isolate the
configuration devices from the target device(s) and cable. One way to
isolate the configuration devices is to add logic, such as a multiplexer, that
can select between the configuration devices and the cable. The
multiplexer device should allow bidirectional transfers on the nSTATUS
and CONF_DONE signals. Another option is to add switches to the five
common signals (CONF_DONE, nSTATUS, DCLK, nCONFIG, and DATA0)
between the cable and the configuration devices. The last option is to
remove the configuration devices from the board when configuring with
the cable. Figure 11–7 shows a combination of a configuration device and
a download cable to configure a Stratix or Stratix GX device.
11–16
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July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–7. Configuring with a Combined PS & Configuration Device Scheme
VCC (1)
VCC (1)
VCC
10 kΩ
10 kΩ
(6)
(2)
10 kΩ
(6)
Stratix or Stratix GX Device
VCC (1)
10 kΩ
MSEL0
MSEL1
MSEL2
nCE
Download Cable
10-Pin Male Header
(PS Mode)
VCC (1)
VCC (1)
(2)
CONF_DONE
nSTATUS
DCLK
10 kΩ
Pin 1
VCC
GND
VIO (3)
nCEO
N.C.
GND
DATA0
nCONFIG
(4)
(4)
(4)
GND
Configuration
Device
(4)
DCLK
DATA
OE (6)
nCS (6)
(4)
nINIT_CONF (5)
Notes to Figure 11–7:
(1)
(2)
(3)
(4)
(5)
(6)
You should connect the pull-up resistor to the same supply voltage as the configuration device.
The pull-up resistors on the DATA0 and DCLK pins are only needed if the download cable is the only configuration
scheme used on the board. This is to ensure that the DATA0 and DCLK pins are not left floating after configuration.
For example, if the design also uses a configuration device, the pull-up resistors on the DATA0 and DCLK pins are
not necessary.
Pin 6 of the header is a VIO reference voltage for the MasterBlaster output driver. VIO should match the target
device’s VCCIO. This is a no-connect pin for the ByteBlasterMV header.
You should not attempt configuration with a download cable while a configuration device is connected to a Stratix
or Stratix GX device. Instead, you should either remove the configuration device from its socket when using the
download cable or place a switch on the five common signals between the download cable and the configuration
device. Remove the download cable when configuring with a configuration device.
If nINIT_CONF is not used, nCONFIG must be pulled to VCC either directly or through a resistor.
If external pull-ups are used on CONF_DONE and nSTATUS pins, they should always be 10 kΩ resistors. You can use
the internal pull-ups of the configuration device only if the CONF_DONE and nSTATUS signals are pulled-up to 3.3 V
or 2.5 V (not 1.8 V or 1.5 V).
f
For more information on how to use the MasterBlaster or ByteBlasterMV
cables, see the following documents:
■
■
■
■
Altera Corporation
July 2005
USB-Blaster USB Port Download Cable Data Sheet
MasterBlaster Serial/USB Communications Cable Data Sheet
ByteBlasterMV Parallel Port Download Cable Data Sheet
ByteBlaster II Parallel Port Download Cable Data Sheet
11–17
Stratix Device Handbook, Volume 2
Configuration Schemes
PS Configuration with a Microprocessor
In PS configuration with a microprocessor, a microprocessor transfers
data from a storage device to the target Stratix or Stratix GX device. To
initiate configuration in this scheme, the microprocessor must generate a
low-to-high transition on the nCONFIG pin and the target device must
release nSTATUS. The microprocessor or programming hardware then
places the configuration data one bit at a time on the DATA0 pin of the
Stratix or Stratix GX device. The least significant bit (LSB) of each data
byte must be presented first. Data is clocked continuously into the target
device until CONF_DONE goes high.
After all configuration data is sent to the Stratix or Stratix GX device, the
CONF_DONE pin goes high to show successful configuration and the start
of initialization. The CONF_DONE pin must have an external 10-kΩ pullup resistor in order for the device to initialize. Initialization, by default,
uses an internal oscillator, which runs at 10 MHz. After initialization, this
internal oscillator is turned off. If you are using the clkusr option, after all
data is transferred clkusr must be clocked an additional 136 times for
the Stratix or Stratix GX device to initialize properly. Driving DCLK to the
device after configuration is complete does not affect device operation.
Handshaking signals are not used in PS configuration modes. Therefore,
the configuration clock speed must be below the specified frequency to
ensure correct configuration. No maximum DCLK period exists. You can
pause configuration by halting DCLK for an indefinite amount of time.
If the target device detects an error during configuration, it drives its
nSTATUS pin low to alert the microprocessor. The microprocessor can
then pulse nCONFIG low to restart the configuration process.
Alternatively, if the Auto-Restart Configuration on Frame Error option
is turned on in the Quartus II software, the target device releases
nSTATUS after a reset time-out period. After nSTATUS is released, the
microprocessor can reconfigure the target device without needing to
pulse nCONFIG low.
The microprocessor can also monitor the CONF_DONE and INIT_DONE
pins to ensure successful configuration. If the microprocessor sends all
data and the initialization clock starts but CONF_DONE and INIT_DONE
have not gone high, it must reconfigure the target device. By default the
INIT_DONE output is disabled. You can enable the INIT_DONE output by
turning on Enable INIT_DONE output option in the Quartus II software.
If you do not turn on the Enable INIT_DONE output option in the
Quartus II software, you are advised to wait for the maximum value of
tCD2UM (see Table 11–8) after the CONF_DONE signal goes high to ensure
the device has been initialized properly and that it has entered user mode.
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July 2005
Configuring Stratix & Stratix GX Devices
During configuration and initialization, and before the device enters user
mode, the microprocessor must not drive the CONF_DONE signal low.
1
If the optional CLKUSR pin is used and nCONFIG is pulled low
to restart configuration during device initialization, you need to
ensure CLKUSR continues toggling during the time nSTATUS is
low (maximum of 40 µs).
Figure 11–8 shows the circuit for PS configuration with a microprocessor.
Figure 11–8. PS Configuration Circuit with Microprocessor
Memory
ADDR
DATA0
VCC
10 k Ω
VCC
VCC
Stratix Device
10 k Ω
MSEL2
CONF_DONE
nSTATUS
MSEL1
MSEL0
nCE
Microprocessor
GND
GND
nCEO
N.C.
DATA0
nCONFIG
DCLK
PS Configuration Timing
Figure 11–9 shows the PS configuration timing waveform for Stratix and
Stratix GX devices. Table 11–8 shows the PS timing parameters for Stratix
and Stratix GX devices.
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July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
Table 11–8. PS Timing Parameters for Stratix & Stratix GX Devices
Symbol
Parameter
Min
Max
Units
tCF2CD
nCONFIG low to CONF_DONE low
800
ns
tCF2ST0
nCONFIG low to nSTATUS low
800
ns
tCF2ST1
nCONFIG high to nSTATUS high
40 (2)
µs
tCFG
nCONFIG low pulse width
40
tSTATUS
nSTATUS low pulse width
10
tCF2CK
nCONFIG high to first rising edge on DCLK
40
µs
µs
40 (2)
µs
tST2CK
nSTATUS high to first rising edge on DCLK
1
µs
tDSU
Data setup time before rising edge on DCLK
7
ns
tDH
Data hold time after rising edge on DCLK
0
ns
tCH
DCLK high time
4
ns
tCL
DCLK low time
4
ns
tCLK
DCLK period
10
ns
fMAX
DCLK maximum frequency
tCD2UM
CONF_DONE high to user mode (1)
6
100
MHz
20
µs
Notes to Table 11–8:
(1)
(2)
The minimum and maximum numbers apply only if the internal oscillator is chosen as the clock source for starting
up the device. If the clock source is CLKUSR, multiply the clock period by 136 to obtain this value.
This value is obtainable if users do not delay configuration by extending the nSTATUS low pulse width.
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July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–9. PS Timing Waveform for Stratix & Stratix GX Devices Note (1)
tCF2ST1
tCFG
tCF2CK
nCONFIG
nSTATUS (2)
tSTATUS
tCF2ST0
t
CLK
CONF_DONE (3)
tCF2CD
tST2CK
tCH tCL
(4)
DCLK
tDH
Bit 0 Bit 1 Bit 2 Bit 3
DATA
Bit n
(4)
tDSU
High-Z
User I/O
User Mode
INIT_DONE
tCD2UM
Notes to Figure 11–9:
(1)
(2)
(3)
(4)
The beginning of this waveform shows the device in user-mode. In user-mode, nCONFIG, nSTATUS, and
CONF_DONE are at logic high levels. When nCONFIG is pulled low, a reconfiguration cycle begins.
Upon power-up, the Stratix II device holds nSTATUS low for the time of the POR delay.
Upon power-up, before and during configuration, CONF_DONE is low.
DCLK should not be left floating after configuration. It should be driven high or low, whichever is convenient.
DATA[] is available as user I/Os after configuration and the state of these pins depends on the dual-purpose pin
settings.
FPP Configuration
Parallel configuration of Stratix and Stratix GX devices meets the
continuously increasing demand for faster configuration times. Stratix
and Stratix GX devices can receive byte-wide configuration data per clock
cycle, and guarantee a configuration time of less than 100 ms with a 100MHz configuration clock. Stratix and Stratix GX devices support
programming data bandwidth up to 800 megabits per second (Mbps) in
this mode. You can use parallel configuration with an EPC16, EPC8, or
EPC4 device, or a microprocessor.
This section discusses the following schemes for FPP configuration in
Stratix and Stratix GX devices:
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■
Altera Corporation
July 2005
FPP Configuration Using an Enhanced Configuration Device
FPP Configuration Using a Microprocessor
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Stratix Device Handbook, Volume 2
Configuration Schemes
FPP Configuration Using an Enhanced Configuration Device
When using FPP with an enhanced configuration device, it supplies data
in a byte-wide fashion to the Stratix or Stratix GX device every DCLK
cycle. See Figure 11–10.
Figure 11–10. FPP Configuration Using Enhanced Configuration Devices
VCC (1) VCC (1)
10 kΩ
Stratix or
Stratix GX Device
10 kΩ
(2)
GND
nCEO
Enhanced
Configuration
Device
DCLK
DATA[7..0]
OE (2)
nCS (2)
nINIT_CONF (3)
DCLK
DATA[7..0]
nSTATUS
CONF_DONE
nCONFIG
MSEL2
MSEL1
MSEL0
(2)
N.C.
nCE
GND
Notes to Figure 11–10:
(1)
(2)
(3)
The pull-up resistors should be connected to the same supply voltage as the
configuration device.
The enhanced configuration devices and EPC2 devices have internal
programmable pull-ups on OE and nCS. You should only use the internal pull-ups
of the configuration device if the nSTATUS and CONF_DONE signals are pulled up
to 3.3 V or 2.5 V (not 1.8 V or 1.5 V). If external pull-ups are used, they should be
10 kΩ.
The nINIT_CONF pin is available on EPC16, EPC8, EPC4, and EPC2 devices. If
nINIT_CONF is not used, nCONFIG must be pulled to VCC through a resistor. The
nINIT_CONF pin has an internal pull-up resistor that is always active in EPC16,
EPC8, EPC4, and EPC2 devices. These devices do not need an external pull-up
resistor on the nINIT_CONF pin.
In the enhanced configuration device scheme, nCONFIG is tied to
nINIT_CONF. On power up, the target Stratix or Stratix GX device senses
the low-to-high transition on nCONFIG and initiates configuration. The
target Stratix or Stratix GX device then drives the open-drain CONF_DONE
pin low, which in-turn drives the enhanced configuration device’s nCS
pin low.
Before configuration starts, there is a 2-ms POR delay if the PORSEL pin
is connected to VCC in the enhanced configuration device. If the PORSEL
pin is connected to ground, the POR delay is 100 ms. When each device
determines that its power is stable, it releases its nSTATUS or OE pin.
Because the enhanced configuration device’s OE pin is connected to the
target Stratix or Stratix GX device’s nSTATUS pin, configuration is
delayed until both the nSTATUS and OE pins are released by each device.
The nSTATUS and OE pins are pulled up by a resistor on their respective
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July 2005
Configuring Stratix & Stratix GX Devices
devices once they are released. When configuring multiple devices,
connect the nSTATUS pins together to ensure configuration only happens
when all devices release their OE or nSTATUS pins. The enhanced
configuration device then clocks data out in parallel to the Stratix or
Stratix GX device using a 66-MHz internal oscillator, or drives it to the
Stratix or Stratix GX device through the EXTCLK pin.
If there is an error during configuration, the Stratix or Stratix GX device
drives the nSTATUS pin low, resetting itself internally and resetting the
enhanced configuration device. The Quartus II software provides an
Auto-restart configuration after error option that automatically initiates
the reconfiguration whenever an error occurs. See the Software Settings
chapter in Volume 2 of the Configuration Handbook for information on how
to turn this option on or off.
If this option is turned off, you must set monitor nSTATUS to check for
errors. To initiate reconfiguration, pulse nCONFIG low. The external
system can pulse nCONFIG if it is under system control rather than tied to
VCC. Therefore, nCONFIG must be connected to nINIT_CONF if you want
to reprogram the Stratix or Stratix GX device on the fly.
When configuration is complete, the Stratix or Stratix GX device releases
the CONF_DONE pin, which is then pulled up by a resistor. This action
disables the EPC16, EPC8, or EPC4 enhanced configuration device as nCS
is driven high. Initialization, by default, uses an internal oscillator, which
runs at 10 MHz. After initialization, this internal oscillator is turned off.
When initialization is complete, the Stratix or Stratix GX device enters
user mode. The enhanced configuration device drives DCLK low before
and after configuration.
1
CONF_DONE goes high one byte early in parallel synchronous
(FPP) and asynchronous (PPA) modes using a microprocessor
with .rbf, .hex, and .ttf file formats. This does not apply to FPP
mode for enhanced configuration devices using .pof file format.
This also does not apply to serial modes.
If, after sending out all of its data, the enhanced configuration device does
not detect CONF_DONE going high, it recognizes that the Stratix or
Stratix GX device has not configured successfully. The enhanced
configuration device pulses its OE pin low for a few microseconds,
driving the nSTATUS pin on the Stratix or Stratix GX device low. If the
Auto-restart configuration after error option is on, the Stratix or Stratix
GX device resets and then pulses its nSTATUS low. When nSTATUS
returns high, reconfiguration is restarted (see Figure 11–11 on
page 11–25).
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July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
Do not drive CONF_DONE low after device configuration to delay
initialization. Instead, use the Enable User-Supplied Start-Up Clock
(CLKUSR) option in the Device & Pin Options dialog box. You can use
this option to synchronize the initialization of multiple devices that are
not in the same configuration chain. Devices in the same configuration
chain initialize together.
After the first Stratix or Stratix GX device completes configuration during
multi-device configuration, its nCEO pin activates the second Stratix or
Stratix GX device’s nCE pin, prompting the second device to begin
configuration. Because CONF_DONE pins are tied together, all devices
initialize and enter user mode at the same time. Because nSTATUS pins
are tied together, configuration stops for the whole chain if any device
(including enhanced configuration devices) detects an error. Also, if the
enhanced configuration device does not detect a high on CONF_DONE at
the end of configuration, it pulses its OE low for a few microseconds to
reset the chain. The low OE pulse drives nSTATUS low on all Stratix and
Stratix GX devices, causing them to enter an error state. This state is
similar to a Stratix or Stratix GX device detecting an error.
If the Auto-restart configuration after error option is on, the Stratix and
Stratix GX devices release their nSTATUS pins after a reset time-out
period. When the nSTATUS pins are released and pulled high, the
configuration device reconfigures the chain. If the Auto-restart
configuration after error option is off, nSTATUS stays low until the
Stratix and Stratix GX devices are reset with a low pulse on nCONFIG.
Figure 11–11 shows the FPP configuration with a configuration device
timing waveform for Stratix and Stratix GX devices.
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Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–11. FPP Configuration with a Configuration Device Timing Waveform Note (1)
nINIT_CONF or VCC/nCONFIG
tPOR
OE/nSTATUS
nCS/CONF_DONE
DCLK
DATA[7..0]
tDSU
tCL
Byte0
Byte1
tCH
tDH
tOEZX
Byte2 Byte3
(2)
Byten
tCO
User I/O
Tri-State
User Mode
Tri-State
INIT_DONE
(3)
Notes to Figure 11–11:
(1)
(2)
(3)
For timing information, see the Enhanced Configuration Devices (EPC4, EPC8 & EPC16) Data Sheet.
The configuration device drives DATA high after configuration.
Stratix and Stratix GX devices enter user mode 136 clock cycles after CONF_DONE goes high.
FPP Configuration Using a Microprocessor
When using a microprocessor for parallel configuration, the
microprocessor transfers data from a storage device to the Stratix or
Stratix GX device through configuration hardware. To initiate
configuration, the microprocessor needs to generate a low-to-high
transition on the nCONFIG pin and the Stratix or Stratix GX device must
release nSTATUS. The microprocessor then places the configuration data
to the DATA[7..0] pins of the Stratix or Stratix GX device. Data is
clocked continuously into the Stratix or Stratix GX device until
CONF_DONE goes high.
The configuration clock (DCLK) speed must be below the specified
frequency to ensure correct configuration. No maximum DCLK period
exists. You can pause configuration by halting DCLK for an indefinite
amount of time.
After all configuration data is sent to the Stratix or Stratix GX device, the
CONF_DONE pin goes high to show successful configuration and the start
of initialization. The CONF_DONE pin must have an external 10-kΩ pullup resistor in order for the device to initialize. Initialization, by default,
uses an internal oscillator, which runs at 10 MHz. After initialization, this
internal oscillator is turned off. If you are using the clkusr option, after all
data is transferred clkusr must be clocked an additional 136 times for
the Stratix or Stratix GX device to initialize properly. Driving DCLK to the
device after configuration is complete does not affect device operation. By
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
default, the INIT_DONE output is disabled. You can enable the
INIT_DONE output by turning on the Enable INIT_DONE output
option in the Quartus II software.
If you do not turn on the Enable INIT_DONE output option in the
Quartus II software, you are advised to wait for maximum value of
tCD2UM (see Table 11–9) after the CONF_DONE signal goes high to ensure
the device has been initialized properly and that it has entered user mode.
During configuration and initialization and before the device enters user
mode, the microprocessor must not drive the CONF_DONE signal low.
1
If the optional CLKUSR pin is used and nCONFIG is pulled low
to restart configuration during device initialization, you need to
ensure CLKUSR continues toggling during the time nSTATUS is
low (maximum of 40 µs).
If the Stratix or Stratix GX device detects an error during configuration, it
drives nSTATUS low to alert the microprocessor. The pin on the
microprocessor connected to nSTATUS must be an input. The
microprocessor can then pulse nCONFIG low to restart the configuration
error. With the Auto-restart configuration after error option on, the
Stratix or Stratix GX device releases nSTATUS after a reset time-out
period. After nSTATUS is released, the microprocessor can reconfigure
the Stratix or Stratix GX device without pulsing nCONFIG low.
The microprocessor can also monitor the CONF_DONE and INIT_DONE
pins to ensure successful configuration. If the microprocessor sends all
the data and the initialization clock starts but CONF_DONE and
INIT_DONE have not gone high, it must reconfigure the Stratix or
Stratix GX device. After waiting the specified 136 DCLK cycles, the
microprocessor should restart configuration by pulsing nCONFIG low.
Figure 11–12 shows the circuit for Stratix and Stratix GX parallel
configuration using a microprocessor.
11–26
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–12. Parallel Configuration Using a Microprocessor
VCC (1)
VCC (1)
Memory
ADDR DATA[7..0]
10 kΩ
10 kΩ
Stratix Device
MSEL2
CONF_DONE
nSTATUS
MSEL1
MSEL0
nCE
Microprocessor
GND
nCEO
GND
N.C.
DATA[7..0]
nCONFIG
DCLK
Note to Figure 11–12:
(1)
The pull-up resistors should be connected to any VCC that meets the Stratix highlevel input voltage (VIH) specification.
For multi-device parallel configuration with a microprocessor, the nCEO
pin of the first Stratix or Stratix GX device is cascaded to the second
device’s nCE pin. The second device in the chain begins configuration
within one clock cycle; therefore, the transfer of data destinations is
transparent to the microprocessor. Because the CONF_DONE pins of the
devices are connected together, all devices initialize and enter user mode
at the same time.
Because the nSTATUS pins are also tied together, if any of the devices
detects an error, the entire chain halts configuration and drives nSTATUS
low. The microprocessor can then pulse nCONFIG low to restart
configuration. If the Auto-restart configuration after error option is on,
the Stratix and Stratix GX devices release nSTATUS after a reset time-out
period. The microprocessor can then reconfigure the devices once
nSTATUS is released. Figure 11–13 shows multi-device configuration
using a microprocessor. Figure 11–14 shows multi-device configuration
when both Stratix and Stratix GX devices are receiving the same data. In
this case, the microprocessor sends the data to both devices
simultaneously, and the devices configure simultaneously.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
Figure 11–13. Parallel Data Transfer in Serial Configuration with a Microprocessor
VCC (1)
10 kΩ
Memory
ADDR DATA[7..0]
VCC (1)
Stratix Device
10 kΩ
Stratix Device
MSEL2
MSEL2
CONF_DONE
nSTATUS
nCE
Microprocessor
MSEL1
MSEL0
CONF_DONE
nSTATUS
nCEO
GND
MSEL1
MSEL0
nCE
GND
nCEO
GND
DATA[7..0]
DATA[7..0]
nCONFIG
nCONFIG
DCLK
DCLK
N.C.
Note to Figure 11–13:
(1)
You should connect the pull-up resistors to any VCC that meets the Stratix high-level input voltage (VIH)
specification.
Figure 11–14. Multiple Device Parallel Configuration with the Same Data Using a Microprocessor
VCC (1)
10 kΩ
Memory
ADDR DATA[7..0]
VCC (1)
Stratix Device
10 kΩ
Stratix Device
MSEL2
CONF_DONE
nSTATUS
nCE
Microprocessor
CONF_DONE
nSTATUS
N.C. (2)
MSEL1
MSEL0
nCE
GND
nCEO
GND
MSEL2
MSEL1
MSEL0
GND
nCEO
GND
DATA[7..0]
DATA[7..0]
nCONFIG
nCONFIG
DCLK
DCLK
N.C. (2)
Notes to Figure 11–14:
(1)
(2)
You should connect the pull-up resistors to any VCC that meets the Stratix high-level input voltage (VIH)
specification.
The nCEO pins are left unconnected when configuring the same data into multiple Stratix or Stratix GX devices.
f
For more information on configuring multiple Altera devices in the same
configuration chain, see the Configuring Mixed Altera FPGA Chains
chapter in the Configuration Handbook, Volume 2.
11–28
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
FPP Configuration Timing
Figure 11–15 shows FPP timing waveforms for configuring a Stratix or
Stratix GX device in FPP mode. Table 11–9 shows the FPP timing
parameters for Stratix or Stratix GX devices.
Figure 11–15. Timing Waveform for Configuring Devices in FPP Mode Note (1)
tCF2ST1
tCFG
tCF2CK
nCONFIG
nSTATUS (2)
tSTATUS
tCF2ST0
t
CLK
CONF_DONE (3)
tCF2CD
tST2CK
tCH tCL
(4)
DCLK
tDH
DATA[7..0}
Byte 0 Byte 1 Byte 2 Byte 3
(4)
User Mode
Byte n
tDSU
User I/O
High-Z
User Mode
INIT_DONE
tCD2UM
Notes to Figure 11–15:
(1)
(2)
(3)
(4)
The beginning of this waveform shows the device in user-mode. In user-mode, nCONFIG, nSTATUS, and
CONF_DONE are at logic high levels. When nCONFIG is pulled low, a reconfiguration cycle begins.
Upon power-up, the Stratix II device holds nSTATUS low for the time of the POR delay.
Upon power-up, before and during configuration, CONF_DONE is low.
DCLK should not be left floating after configuration. It should be driven high or low, whichever is convenient.
DATA[] is available as user I/Os after configuration and the state of these pins depends on the dual-purpose pin
settings.
Table 11–9. FPP Timing Parameters for Stratix & Stratix GX Devices (Part 1 of 2)
Symbol
Parameter
Min
Max
Units
tCF2CK
nCONFIG high to first rising edge on DCLK
40
µs
tDSU
Data setup time before rising edge on DCLK
7
ns
tDH
Data hold time after rising edge on DCLK
0
ns
tCFG
nCONFIG low pulse width
40
µs
tCH
DCLK high time
4
ns
tCL
DCLK low time
4
ns
tCLK
DCLK period
10
ns
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
Table 11–9. FPP Timing Parameters for Stratix & Stratix GX Devices (Part 2 of 2)
Symbol
Parameter
fMAX
DCLK frequency
tCD2UM
CONF_DONE high to user mode (1)
tCF2CD
Min
6
Max
Units
100
MHz
20
µs
nCONFIG low to CONF_DONE low
800
ns
tCF2ST0
nCONFIG low to nSTATUS low
800
ns
tCF2ST1
nCONFIG high to nSTATUS high
40 (2)
µs
tSTATUS
nSTATUS low pulse width
10
40 (2)
µs
tST2CK
nSTATUS high to firstrising edge of DCLK
1
µs
Notes to Table 11–9:
(1)
(2)
The minimum and maximum numbers apply only if the internal oscillator is chosen as the clock source for starting
up the device. If the clock source is CLKUSR, multiply the clock period by 136 to obtain this value.
This value is obtainable if users do not delay configuration by extending the nSTATUS low pulse width.
PPA Configuration
In PPA schemes, a microprocessor drives data to the Stratix or Stratix GX
device through a download cable. When using a PPA scheme, use a 1-kΩ
pull-up resistor to pull the DCLK pin high to prevent unused
configuration pins from floating.
To begin configuration, the microprocessor drives nCONFIG high and
then asserts the target device’s nCS pin low and CS pin high. Next, the
microprocessor places an 8-bit configuration word on the target device’s
data inputs and pulses nWS low. On the rising edge of nWS, the target
device latches a byte of configuration data and then drives its RDYnBSY
signal low, indicating that it is processing the byte of configuration data.
The microprocessor then performs other system functions while the
Stratix or Stratix GX device is processing the byte of configuration data.
Next, the microprocessor checks nSTATUS and CONF_DONE. If nSTATUS
is high and CONF_DONE is low, the microprocessor sends the next data
byte. If nSTATUS is low, the device is signaling an error and the
microprocessor should restart configuration. However, if nSTATUS is
high and all the configuration data is received, the device is ready for
initialization. At the beginning of initialization, CONF_DONE goes high to
indicate that configuration is complete. The CONF_DONE pin must have
an external 10-kΩ pull-up resistor in order for the device to initialize.
Initialization, by default, uses an internal oscillator, which runs at
10 MHz. After initialization, this internal oscillator is turned off. When
initialization is complete, the Stratix or Stratix GX device enters user
mode.
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Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–16 shows the PPA configuration circuit. An optional address
decoder controls the device’s nCS and CS pins. This decoder allows the
microprocessor to select the Stratix or Stratix GX device by accessing a
particular address, simplifying the configuration process.
Figure 11–16. PPA Configuration Circuit
VCC (1)
10 kΩ
Address Decoder
ADDR
VCC (1)
Memory
10 kΩ
VCC (1)
ADDR DATA[7..0]
10 k Ω
VCC
Stratix Device
nCS
MSEL2
CS
MSEL1
CONF_DONE
MSEL0
nSTATUS
GND
nCE
Microprocessor
nCEO
GND
N.C.
VCC (1)
DATA[7..0]
nWS
nRS
10 kΩ
nCONFIG
RDYnBSY
DCLK
Note to Figure 11–16:
(1)
The pull-up resistor should be connected to the same supply voltage as the Stratix or Stratix GX device.
The device’s nCS or CS pins can be toggled during PPA configuration if
the design meets the specifications for tCSSU, tWSP, and tCSH given in
Table 11–10 on page 11–36. The microprocessor can also directly control
the nCS and CS signals. You can tie one of the nCS or CS signals to its
active state (i.e., nCS may be tied low) and toggle the other signal to
control configuration.
Stratix and Stratix GX devices can serialize data internally without the
microprocessor. When the Stratix or Stratix GX device is ready for the
next byte of configuration data, it drives RDYnBSY high. If the
microprocessor senses a high signal when it polls RDYnBSY, the
microprocessor strobes the next byte of configuration data into the
device. Alternatively, the nRS signal can be strobed, causing the
RDYnBSY signal to appear on DATA7. Because RDYnBSY does not need to
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July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
be monitored, reading the state of the configuration data by strobing nRS
low saves a system I/O port. Do not drive data onto the data bus while
nRS is low because it causes contention on DATA7. If the nRS pin is not
used to monitor configuration, you should tie it high. To simplify
configuration, the microprocessor can wait for the total time of
tBUSY (max) + tRDY2WS + tW2SB before sending the next data bit.
After configuration, the nCS, CS, nRS, nWS, and RDYnBSY pins act as user
I/O pins. However, if the PPA scheme is chosen in the Quartus II
software, these I/O pins are tri-stated by default in user mode and should
be driven by the microprocessor. To change the default settings in the
Quartus II software, select Device & Pin Option (Compiler Setting
menu).
If the Stratix or Stratix GX device detects an error during configuration, it
drives nSTATUS low to alert the microprocessor. The microprocessor can
then pulse nCONFIG low to restart the configuration process.
Alternatively, if the Auto-Restart Configuration on Frame Error option
is turned on, the Stratix or Stratix GX device releases nSTATUS after a
reset time-out period. After nSTATUS is released, the microprocessor can
reconfigure the Stratix or Stratix GX device. At this point, the
microprocessor does not need to pulse nCONFIG low.
The microprocessor can also monitor the CONF_DONE and INIT_DONE
pins to ensure successful configuration. The microprocessor must
monitor the nSTATUS pin to detect errors and the CONF_DONE pin to
determine when programming completes (CONF_DONE goes high one
byte early in parallel mode). If the microprocessor sends all configuration
data and starts initialization but CONF_DONE is not asserted, the
microprocessor must reconfigure the Stratix or Stratix GX device.
By default, the INIT_DONE is disabled. You can enable the INIT_DONE
output by turning on the Enable INIT_DONE output option in the
Quartus II software. If you do not turn on the Enable INIT_DONE
output option in the Quartus II software, you are advised to wait for the
maximum value of tCD2UM (see Table 11–10) after the CONF_DONE signal
goes high to ensure the device has been initialized properly and that it has
entered user mode.
During configuration and initialization, and before the device enters user
mode, the microprocessor must not drive the CONF_DONE signal low.
1
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Stratix Device Handbook, Volume 2
If the optional CLKUSR pin is used and nCONFIG is pulled low
to restart configuration during device initialization, you need to
ensure that CLKUSR continues toggling during the time
nSTATUS is low (maximum of 40 μs).
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
You can also use PPA mode to configure multiple Stratix and Stratix GX
devices. Multi-device PPA configuration is similar to single-device PPA
configuration, except that the Stratix and Stratix GX devices are cascaded.
After you configure the first Stratix or Stratix GX device, nCEO is asserted,
which asserts the nCE pin on the second device, initiating configuration.
Because the second Stratix or Stratix GX device begins configuration
within one write cycle of the first device, the transfer of data destinations
is transparent to the microprocessor. All Stratix and Stratix GX device
CONF_DONE pins are tied together; therefore, all devices initialize and
enter user mode at the same time. See Figure 11–17.
Figure 11–17. PPA Multi-Device Configuration Circuit
VCC (2)
VCC (2)
VCC (2)
10 kΩ
10 kΩ
VCC (3)
10 kΩ
10 kΩ
Address Decoder
VCC (2)
ADDR
Memory
10 kΩ
ADDR DATA[7..0]
Stratix Device 1
DATA[7..0]
nCS
CS (1)
CONF_DONE
nSTATUS
Microprocessor
Stratix Device 2
nCE
GND
DCLK
nCEO
nWS
nRS
nCONFIG
RDYnBSY
VCC
MSEL2
MSEL1
MSEL0
GND
DATA[7..0]
DCLK
nCS
CS (1)
CONF_DONE
nSTATUS
nCE
nCEO
nWS
nRS
MSEL2
nCONFIG
MSEL1
RDYnBSY
MSEL0
N.C.
VCC
GND
Notes to Figure 11–17:
(1)
(2)
If not used, you can connect the CS pin to VCC directly. If not used, the nCS pin can be connected to GND directly.
Connect the pull-up resistor to the same supply voltage as the Stratix or Stratix GX device.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
PPA Configuration Timing
Figure 11–18 shows the Stratix and Stratix GX device timing waveforms
for PPA configuration.
Figure 11–18. PPA Timing Waveforms for Stratix & Stratix GX Devices
tCFG tCF2ST1
nCONFIG
nSTATUS (1)
CONF_DONE (2)
Byte 0
DATA[7..0]
Byte 1
Byte n Ð 1
Byte n
tDSU
tCSSU
tCF2WS
CS (3)
(4)
tDH
tCSSU
(4)
nCS (3)
tWSP
tCSH
(4)
nWS (3)
tRDY2WS
(4)
RDYnBSY (3)
tWS2B
tSTATUS
tCF2ST0
tCF2CD
User I/Os
tBUSY
tCD2UM
High-Z
(4)
INIT_DONE
Notes to Figure 11–18:
(1)
(2)
(3)
(4)
Upon power-up, nSTATUS is held low for the time of the POR delay.
Upon power-up, before and during configuration, CONF_DONE is low.
After configuration, the state of CS, nCS, nWS, and RDYnBSY depends on the design programmed into the Stratix or
Stratix GX device.
Device I/O pins are in user mode.
11–34
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–19 shows the Stratix and Stratix GX timing waveforms when
using strobed nRS and nWS signals.
Figure 11–19. PPA Timing Waveforms Using Strobed nRS & nWS Signals
tCF2ST1
tCFG
nCONFIG
nSTATUS
tCF2SCD
tCF2ST0
tSTATUS
CONF_DONE
tCSSU
(2)
nCS (1)
tCSH
(2)
CS (1)
tDH
Byte 0
DATA[7..0]
Byte 1
Byte n
(3)
tDSU
(2)
nWS
tWSP
nRS
INIT_DONE
User I/O
tRS2WS
tWS2RS
tCF2WS
(2)
tWS2RS
tRSD7
tRDY2WS
(2)
tWS2B
(2)
DATA7/RDYnBSY (4)
tCD2UM
tBUSY
Notes to Figure 11–19:
(1)
(2)
(3)
(4)
The user can toggle nCS or CS during configuration if the design meets the specification for tCSSU, tWSP, and tCSH.
Device I/O pins are in user mode.
The DATA[7..0] pins are available as user I/Os after configuration and the state of theses pins depends on the
dual-purpose pin settings. Do not leave DATA[7..0] floating. If these pins are not used in user-mode, you should
drive them high or low, whichever is more convenient.
DATA7 is a bidirectional pin. It represents an input for data input, but represents an output to show the status of
RDYnBSY.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
Table 11–10 defines the Stratix and Stratix GX timing parameters for PPA
configuration
Table 11–10. PPA Timing Parameters for Stratix & Stratix GX Devices
Symbol
Parameter
Min
Max
Units
tCF2WS
nCONFIG high to first rising edge on nWS
40
µs
tDSU
Data setup time before rising edge on nWS
10
ns
tDH
Data hold time after rising edge on nWS
0
ns
tCSSU
Chip select setup time before rising edge on nWS
10
ns
tCSH
Chip select hold time after rising edge on nWS
0
ns
tWSP
nWS low pulse width
15
ns
40
tCFG
nCONFIG low pulse width
tWS2B
nWS rising edge to RDYnBSY low
tBUSY
RDYnBSY low pulse width
tRDY2WS
RDYnBSY rising edge to nWS rising edge
15
ns
tWS2RS
nWS rising edge to nRS falling edge
15
ns
tRS2WS
nRS rising edge to nWS rising edge
15
ns
tRSD7
nRS falling edge to DATA7 valid with RDYnBSY signal
7
µs
20
ns
45
ns
20
ns
CONF_DONE high to user mode (1)
6
20
µs
nSTATUS low pulse width
10
40 (2)
µs
800
ns
tCD2UM
tSTATUS
tCF2CD
nCONFIG low to CONF_DONE low
tCF2ST0
nCONFIG low to nSTATUS low
tCF2ST1
nCONFIG high to nSTATUS high
800
ns
40 (2)
µs
Notes to Table 11–10:
(1)
(2)
The minimum and maximum numbers apply only if the internal oscillator is chosen as the clock source for starting
up the device. If the clock source is CLKUSR, multiply the clock period by 136 to obtain this value.
This value is obtained if you do not delay configuration by extending the nstatus to low pulse width.
f
For information on how to create configuration and programming files
for this configuration scheme, see the Software Settings section in the
Configuration Handbook, Volume 2.
JTAG Programming & Configuration
The JTAG has developed a specification for boundary-scan testing. This
boundary-scan test (BST) architecture offers the capability to efficiently
test components on printed circuit boards (PCBs) with tight lead spacing.
The BST architecture can test pin connections without using physical test
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Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
probes and capture functional data while a device is operating normally.
You can also use the JTAG circuitry to shift configuration data into the
device.
f
For more information on JTAG boundary-scan testing, see AN 39: IEEE
1149.1 (JTAG) Boundary-Scan Testing in Altera Devices.
To use the SignalTap® II embedded logic analyzer, you need to connect
the JTAG pins of your Stratix device to a download cable header on your
PCB.
f
For more information on SignalTap II, see the Design Debugging Using
SignalTap II Embedded Logic Analyzer chapter in the Quartus II Handbook,
Volume 2.
A device operating in JTAG mode uses four required pins, TDI, TDO, TMS,
and TCK, and one optional pin, TRST. The four JTAG input pins (TDI,
TMS, TCK and TRST) have weak, internal pull-up resistors, whose values
range from 20 to 40 kΩ. All other pins are tri-stated during JTAG
configuration. Do not begin JTAG configuration until all other
configuration is complete. Table 11–11 shows each JTAG pin’s function.
Table 11–11. JTAG Pin Descriptions
Pin
Description
Function
TDI
Test data input
Serial input pin for instructions as well as test and programming data. Data is
shifted in on the rising edge of TCK. The VCCSEL pin controls the input buffer
selection.
TDO
Test data output
Serial data output pin for instructions as well as test and programming data. Data
is shifted out on the falling edge of TCK. The pin is tri-stated if data is not being
shifted out of the device. The high level output voltage is determined by VCCIO.
TMS
Test mode select
Input pin that provides the control signal to determine the transitions of the Test
Access Port (TAP) controller state machine. Transitions within the state machine
occur on the rising edge of TCK. Therefore, TMS must be set up before the rising
edge of TCK. TMS is evaluated on the rising edge of TCK. The VCCSEL pin
controls the input buffer selection.
TCK
Test clock input
The clock input to the BST circuitry. Some operations occur at the rising edge,
while others occur at the falling edge. The VCCSEL pin controls the input buffer
selection.
TRST Test reset input
Active-low input to asynchronously reset the boundary-scan circuit. The TRST
pin is optional according to IEEE Std. 1149.1. The VCCSEL pin controls the input
buffer selection.
(optional)
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
During JTAG configuration, data is downloaded to the device on the PCB
through the MasterBlaster or ByteBlasterMV header. Configuring devices
through a cable is similar to programming devices in-system. One
difference is to connect the TRST pin to VCC to ensure that the TAP
controller is not reset. See Figure 11–20.
Figure 11–20. JTAG Configuration of a Single Device
VCC (1)
1 kΩ
VCC
VCC (1)
10 kΩ
VCC
10 kΩ
Stratix or
Stratix GX Device
nCE
TCK
TDO
TRST
nSTATUS
CONF_DONE
nCONFIG
MSEL0
MSEL1
MSEL2
DATA0
DCLK
TMS
TDI
GND
VCC
(2)
(2)
(2)
(2)
(2)
(2)
1 kΩ
MasterBlaster or ByteBlasterMV
10-Pin Male Header
(Top View)
Pin 1
VCC (1)
GND
VIO (3)
1 kΩ
GND
GND
Notes to Figure 11–20:
(1)
(2)
(3)
You should connect the pull-up resistor to the same supply voltage as the
download cable.
You should connect the nCONFIG, MSEL0, and MSEL1 pins to support a non-JTAG
configuration scheme. If you only use JTAG configuration, connect nCONFIG to
VCC, and MSEL0, MSEL1, and MSEL2 to ground. Pull DATA0 and DCLK to high or
low.
VIO is a reference voltage for the MasterBlaster output driver. VIO should match the
device’s VCCIO. See the MasterBlaster Serial/USB Communications Cable Data Sheet for
this value.
To configure a single device in a JTAG chain, the programming software
places all other devices in BYPASS mode. In BYPASS mode, devices pass
programming data from the TDI pin to the TDO pin through a single
bypass register without being affected internally. This scheme enables the
programming software to program or verify the target device.
Configuration data driven into the device appears on the TDO pin one
clock cycle later.
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Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Stratix and Stratix GX devices have dedicated JTAG pins. You can
perform JTAG testing on Stratix and Stratix GX devices before and after,
but not during configuration. The chip-wide reset and output enable pins
on Stratix and Stratix GX devices do not affect JTAG boundary-scan or
programming operations. Toggling these pins does not affect JTAG
operations (other than the usual boundary-scan operation).
When designing a board for JTAG configuration of Stratix and Stratix GX
devices, you should consider the regular configuration pins. Table 11–12
shows how you should connect these pins during JTAG configuration.
Table 11–12. Dedicated Configuration Pin Connections During JTAG Configuration
Signal
Description
nCE
On all Stratix and Stratix GX devices in the chain, nCE should be driven low by connecting it to
ground, pulling it low via a resistor, or driving it by some control circuitry. For devices that are also
in multi-device PS, FPP or PPA configuration chains, the nCE pins should be connected to GND
during JTAG configuration or JTAG configured in the same order as the configuration chain.
nCEO
On all Stratix and Stratix GX devices in the chain, nCEO can be left floating or connected to the
nCE of the next device. See nCE pin description above.
MSEL
These pins must not be left floating. These pins support whichever non-JTAG configuration is used
in production. If only JTAG configuration is used, you should tie both pins to ground.
nCONFIG
nCONFIG must be driven high through the JTAG programming process. Driven high by connecting
to VC C , pulling high via a resistor, or driven by some control circuitry.
nSTATUS
Pull to VC C via a 10-kΩ resistor. When configuring multiple devices in the same JTAG chain, each
nSTATUS pin should be pulled up to VC C individually. nSTATUS pulling low in the middle of JTAG
configuration indicates that an error has occurred.
CONF_DO
NE
Pull to VC C via a 10-kΩ resistor. When configuring multiple devices in the same JTAG chain, each
CONF_DONE pin should be pulled up to VC C individually. CONF_DONE going high at the end of
JTAG configuration indicates successful configuration.
DCLK
Should not be left floating. Drive low or high, whichever is more convenient on your board.
DATA0
Should not be left floating. Drive low or high, whichever is more convenient on your board.
JTAG Programming & Configuration of Multiple Devices
When programming a JTAG device chain, one JTAG-compatible header,
such as the ByteBlasterMV header, is connected to several devices. The
number of devices in the JTAG chain is limited only by the drive capacity
of the download cable. However, when more than five devices are
connected in a JTAG chain, Altera recommends buffering the TCK, TDI,
and TMS pins with an on-board buffer.
Altera Corporation
July 2005
11–39
Stratix Device Handbook, Volume 2
Configuration Schemes
JTAG-chain device programming is ideal when the PCB contains multiple
devices, or when testing the PCB using JTAG BST circuitry. Figure 11–21
shows multi-device JTAG configuration.
Figure 11–21. Multi-Device JTAG Configuration Notes (1), (2)
VCC
MasterBlaster or ByteBlasterMV
10-Pin Male Header
VCC
10 kΩ
10 kΩ
10 kΩ
Stratix Device
VCC
VCC
VCC
10 kΩ
VCC
10 kΩ
Stratix Device
10 kΩ
Stratix Device
VCC
Pin 1
1 kΩ
VCC
VCC
1 kΩ
VIO
(4)
(3)
(3)
(3)
(3)
(3)
(3)
(5)
nSTATUS
DATA0
DCLK
nCONFIG
MSEL2 CONF_DONE
MSEL1
MSEL0
nCE
TDI
TMS
TCK
TDO
(3)
(3)
(3)
(3)
(3)
(3)
(5)
nSTATUS
DATA0
DCLK
nCONFIG
MSEL2 CONF_DONE
MSEL1
MSEL0
nCE
TDI
TMS
TDO
TCK
nSTATUS
(3)
(3)
(3)
(3)
(3)
(3)
(5)
DATA0
DCLK
nCONFIG
MSEL2 CONF_DONE
MSEL1
MSEL0
nCE
TDI
TMS
TDO
TCK
1 kΩ
Notes to Figure 11–21:
(1)
(2)
(3)
(4)
(5)
Stratix, Stratix GX, APEXTM II, APEX 20K, MercuryTM, ACEX® 1K, and FLEX® 10K devices can be placed within the
same JTAG chain for device programming and configuration.
For more information on all configuration pins connected in this mode, see Table 11–11 on page 11–37.
Connect the nCONFIG, MSEL0, MSEL1, and MSEL2 pins to support a non-JTAG configuration scheme. If only JTAG
configuration is used, connect nCONFIG to VCC, and MSEL0, MSEL1, and MSEL2 to ground. Pull DATA0 and DCLK
to either high or low.
VIO is a reference voltage for the MasterBlaster output driver. VIO should match the device’s VCCIO. See the
MasterBlaster Serial/USB Communications Cable Data Sheet for this value.
nCE must be connected to GND or driven low for successful JTAG configuration.
The nCE pin must be connected to GND or driven low during JTAG
configuration. In multi-device PS, FPP and PPA configuration chains, the
first device's nCE pin is connected to GND while its nCEO pin is connected
to nCE of the next device in the chain. The last device's nCE input comes
from the previous device, while its nCEO pin is left floating. After the first
device completes configuration in a multi-device configuration chain, its
nCEO pin drives low to activate the second device's nCE pin, which
prompts the second device to begin configuration. Therefore, if these
devices are also in a JTAG chain, you should make sure the nCE pins are
connected to GND during JTAG configuration or that the devices are JTAG
configured in the same order as the configuration chain. As long as the
devices are JTAG configured in the same order as the multi-device
configuration chain, the nCEO of the previous device drives nCE of the
next device low when it has successfully been JTAG configured.
11–40
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
The Quartus II software verifies successful JTAG configuration upon
completion. The software checks the state of CONF_DONE through the
JTAG port. If CONF_DONE is not in the correct state, the Quartus II
software indicates that configuration has failed. If CONF_DONE is in the
correct state, the software indicates that configuration was successful.
1
If VCCIO is tied to 3.3 V, both the I/O pins and JTAG TDO port
drive at 3.3-V levels.
Do not attempt JTAG and non-JTAG configuration simultaneously. When
configuring through JTAG, allow any non-JTAG configuration to
complete first.
Figure 11–22 shows the JTAG configuration of a Stratix or Stratix GX
device with a microprocessor.
Figure 11–22. JTAG Configuration of Stratix & Stratix GX Devices with a
Microprocessor
Stratix or
Stratix GX Device
Memory
ADDR
DATA
(1)
(2)
(2)
Microprocessor
MSEL2
MSEL1
nCONFIG MSEL0
DATA0
DCLK
TDI
TCK
TDO
TMS
nSTATUS
(1)
(1)
(1)
VCC
VCC
10 kΩ
10 kΩ
CONF_DONE
Notes to Figure 11–22:
(1)
(2)
Connect the nCONFIG, MSEL2, MSEL1, and MSEL0 pins to support a non-JTAG
configuration scheme. If your design only uses JTAG configuration, connect the
nCONFIG pin to VCC and the MSEL2, MSEL1, and MSEL0 pins to ground.
Pull DATA0 and DCLK to either high or low.
Configuration with JRunner Software Driver
JRunner is a software driver that allows you to configure Altera FPGAs
through the ByteBlasterMV download cable in JTAG mode. The
programming input file supported is in Raw Binary File (.rbf) format.
JRunner also requires a Chain Description File (.cdf) generated by the
Quartus II software. JRunner is targeted for embedded JTAG
configuration. The source code has been developed for the Windows NT
operating system. You can customize the code to make it run on other
platforms.
Altera Corporation
July 2005
11–41
Stratix Device Handbook, Volume 2
Configuration Schemes
f
For more information on the JRunner software driver, see the JRunner
Software Driver: An Embedded Solution to the JTAG Configuration White
Paper and zip file.
Jam STAPL Programming & Test Language
The JamTM Standard Test and Programming Language (STAPL), JEDEC
standard JESD-71, is a standard file format for in-system
programmability (ISP) purposes. Jam STAPL supports programming or
configuration of programmable devices and testing of electronic systems,
using the IEEE 1149.1 JTAG interface. Jam STAPL is a freely licensed open
standard.
Connecting the JTAG Chain to the Embedded Processor
There are two ways to connect the JTAG chain to the embedded processor.
The most straightforward method is to connect the embedded processor
directly to the JTAG chain. In this method, four of the processor pins are
dedicated to the JTAG interface, saving board space but reducing the
number of available embedded processor pins.
Figure 11–23 illustrates the second method, which is to connect the JTAG
chain to an existing bus through an interface PLD. In this method, the
JTAG chain becomes an address on the existing bus. The processor then
reads from or writes to the address representing the JTAG chain.
11–42
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–23. Embedded System Block Diagram
Embedded System
TDI
TMS
to/from ByteBlasterMV
Interface
Logic
(Optional)
TCK
TDO
TDI
Control
Control
8
d[7..0]
4
TMS
TDI
TCK
d[3..0]
Any JTAG
Device
TMS
TDO
TCK
20
adr[19..0]
TDO
Embedded
Processor
MAX® 9000,
MAX 9000A,
MAX 7000S,
MAX 7000A,
MAX 7000AE,
or MAX 3000
Device
TDI
Control
8
d[7..0]
TMS
EPROM or
System
Memory
TCK
TDO
adr[19..0]
20
20
VCC VCC
adr[19..0]
VCC
TDI
TMS
TCK
10 kΩ
TRST
nSTATUS
CONF_DONE
nCONFIG
MSEL0
MSEL1
nCE
TDO
10 kΩ
Any Cyclone,
FLEX 10K,
FLEX 10KA,
FLEX10KE,
APEX 20K,
or APEX 20KE
Device
GND
TDI
TMS
TCK
(2)
(2)
DATA0
(1)
nCONFIG
DCLK
MSEL1
(1)
MSEL0
(1)
Cyclone FPGA
TDO
Notes to Figure 11–23:
(1)
(2)
Connect the nCONFIG, MSEL2, MSEL1, and MSEL0 pins to support a non-JTAG configuration scheme. If your design
only uses JTAG configuration, connect the nCONFIG pin to VCC and the MSEL2, MSEL1, and MSEL0 pins to ground.
Pull DATA0 and DCLK to either high or low.
Both JTAG connection methods should include space for the
MasterBlaster or ByteBlasterMV header connection. The header is useful
during prototyping because it allows you to verify or modify the Stratix
or Stratix GX device’s contents. During production, you can remove the
header to save cost.
Altera Corporation
July 2005
11–43
Stratix Device Handbook, Volume 2
Configuration Schemes
Program Flow
The Jam Player provides an interface for manipulating the IEEE
Std. 1149.1 JTAG TAP state machine. The TAP controller is a 16-state state
machine that is clocked on the rising edge of TCK, and uses the TMS pin to
control JTAG operation in a device. Figure 11–24 shows the flow of an
IEEE Std. 1149.1 TAP controller state machine.
11–44
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–24. JTAG TAP Controller State Machine
TMS = 1
TEST_LOGIC/
RESET
TMS = 0
SELECT_DR_SCAN
SELECT_IR_SCAN
TMS = 1
TMS = 1
TMS = 0
TMS = 1
RUN_TEST/
IDLE
TMS = 0
TMS = 0
TMS = 1
TMS = 1
CAPTURE_IR
CAPTURE_DR
TMS = 0
TMS = 0
SHIFT_DR
SHIFT_IR
TMS = 0
TMS = 0
TMS = 1
TMS = 1
TMS = 1
TMS = 1
EXIT1_DR
EXIT1_IR
TMS = 0
TMS = 0
PAUSE_DR
PAUSE_IR
TMS = 0
TMS = 1
TMS = 0
TMS = 1
TMS = 0
TMS = 0
EXIT2_DR
EXIT2_IR
TMS = 1
TMS = 1
TMS = 1
TMS = 1
UPDATE_DR
TMS = 0
UPDATE_IR
TMS = 0
While the Jam Player provides a driver that manipulates the TAP
controller, the Jam Byte-Code File (.jbc) provides the high-level
intelligence needed to program a given device. All Jam instructions that
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Configuration Schemes
send JTAG data to the device involve moving the TAP controller through
either the data register leg or the instruction register leg of the state
machine. For example, loading a JTAG instruction involves moving the
TAP controller to the SHIFT_IR state and shifting the instruction into the
instruction register through the TDI pin. Next, the TAP controller is
moved to the RUN_TEST/IDLE state where a delay is implemented to
allow the instruction time to be latched. This process is identical for data
register scans, except that the data register leg of the state machine is
traversed.
The high-level Jam instructions are the DRSCAN instruction for scanning
the JTAG data register, the IRSCAN instruction for scanning the
instruction register, and the WAIT command that causes the state machine
to sit idle for a specified period of time. Each leg of the TAP controller is
scanned repeatedly, according to instructions in the JBC file, until all of
the target devices are programmed.
Figure 11–25 illustrates the functional behavior of the Jam Player when it
parses the JBC file. When the Jam Player encounters a DRSCAN, IRSCAN,
or WAIT instruction, it generates the proper data on TCK, TMS, and TDI to
complete the instruction. The flow diagram shows branches for the
DRSCAN, IRSCAN, and WAIT instructions. Although the Jam Player
supports other instructions, they are omitted from the flow diagram for
simplicity.
11–46
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Figure 11–25. Jam Player Flow Diagram (Part 1 of 2)
Start
Set TMS to 1
and Pulse TCK
Five Times
Test-Logic-Reset
Set TMS to 0
and Pulse TCK
Run-Test/Idle
Switch
WAIT
Read Instruction
from the Jam
File
EOF?
F
T
Case[]
DRSCAN
IRSCAN
Set TMS to 0
and Pulse TCK
Parse Argument
Parse Argument
Run-Test/Idle
Set TMS to 1
and Pulse TCK
Twice
Delay
Set TMS to 1
and Pulse TCK
Select-IR-Scan
Set TMS to 1
and Pulse TCK
Three Times
Set TMS to 0
and Pulse TCK
Twice
Set TMS to 0
and Pulse TCK
Twice
Switch
Test-Logic-Reset
Shift-DR
Shift-IR
Set TMS to 0
and Pulse TCK
and Write TDI
End
Set TMS to 1
and Pulse TCK
Select-DR-Scan
Set TMS to 0
and Pulse TCK
and Write TDI
Shift-IR
Shift-DR
Exit1-IR
Set TMS to 0
and Pulse TCK
Pause-IR
Set TMS to 1
and Pulse TCK
Twice
T
EOF
Shift-IR
Continued on
Part 2 of
Flow Diagram
F
Set TMS to 0
and Pulse TCK
and Write TDI
Update-IR
Set TMS to 0
and Pulse TCK
Run-Test/Idle
Switch
Altera Corporation
July 2005
11–47
Stratix Device Handbook, Volume 2
Configuration Schemes
Figure 11–26. Jam Player Flow Diagram (Part 2 of 2)
Continued from
Part 1 of
Flow Diagram
Compare
Case[]
Default
Capture
Set TMS to 1
and Pulse TCK
and Store TDO
F
Exit1-DR
Loop<
DR Length
F
Set TMS to 1
and Pulse TCK
and Store TDO
Set TMS to 1
and Pulse TCK
Update-IR
Shift-DR
T
Set TMS to 0
and Pulse TCK,
Write TDI, and
Store TDO
Exit1-DR
T
Set TMS to 0
and Pulse TCK,
Write TDI, and
Store TDO
Loop<
DR Length
Correct F
TDO Value
Report
Error
Set TMS to 0
and Pulse TCK
Set TMS to 1
and Pulse TCK
and Store TDO
F
Loop<
DR Length
Run-Test/Idle
Exit1-DR
T
T
Switch
Set TMS to 1
and Pulse TCK
Set TMS to 1
and Pulse TCK
Update-IR
Set TMS to 0
and Pulse TCK
and Write TDI
Update-IR
Set TMS to 0
and Pulse TCK
Run-Test/Idle
Switch
Set TMS to 0
and Pulse TCK
Run-Test/Idle
Switch
Execution of a Jam program starts at the beginning of the program. The
program flow is controlled using GOTO, CALL/RETURN, and FOR/NEXT
structures. The GOTO and CALL statements see labels that are symbolic
names for program statements located elsewhere in the Jam program. The
language itself enforces almost no constraints on the organizational
structure or control flow of a program.
1
11–48
Stratix Device Handbook, Volume 2
The Jam language does not support linking multiple Jam
programs together or including the contents of another file into
a Jam program.
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Jam Instructions
Each Jam statement begins with one of the instruction names listed in
Table 11–13. The instruction names, including the names of the optional
instructions, are reserved keywords that you cannot use as variable or
label identifiers in a Jam program.
Table 11–13. Instruction Names
BOOLEAN
INTEGER
PREIR
CALL
IRSCAN
PRINT
CRC
IRSTOP
PUSH
DRSCAN
LET
RETURN
DRSTOP
NEXT
STATE
EXIT
NOTE
WAIT
EXPORT
POP
VECTOR (1)
FOR
POSTDR
VMAP (1)
GOTO
POSTIR
–
IF
PREDR
–
Note to Table 11–13:
(1)
This instruction name is an optional language extension.
Table 11–14 shows the state names that are reserved keywords in the Jam
language. These keywords correspond to the state names specified in the
IEEE Std. 1149.1 JTAG specification.
Table 11–14. Reserved Keywords (Part 1 of 2)
IEEE Std. 1149.1 JTAG State Names
Altera Corporation
July 2005
Jam Reserved State Names
Test-Logic-Reset
RESET
Run-Test-Idle
IDLE
Select-DR-Scan
DRSELECT
Capture-DR
DRCAPTURE
Shift-DR
DRSHIFT
Exit1-DR
DREXIT1
Pause-DR
DRPAUSE
Exit2-DR
DREXIT2
Update-DR
DRUPDATE
Select-IR-Scan
IRSELECT
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Stratix Device Handbook, Volume 2
Configuration Schemes
Table 11–14. Reserved Keywords (Part 2 of 2)
IEEE Std. 1149.1 JTAG State Names
Jam Reserved State Names
Capture-IR
IRCAPTURE
Shift-IR
IRSHIFT
Exit1-IR
IREXIT1
Pause-IR
IRPAUSE
Exit2-IR
IREXIT2
Update-IR
IRUPDATE
Example Jam File that Reads the IDCODE
Figure 11–27 illustrates the flexibility and utility of the Jam STAPL. The
example reads the IDCODE out of a single device in a JTAG chain.
1
The array variable, I_IDCODE, is initialized with the IDCODE
instruction bits ordered the LSB first (on the left) to most
significant bit (MSB) (on the right). This order is important
because the array field in the IRSCAN instruction is always
interpreted, and sent, MSB to LSB.
Figure 11–27. Example Jam File Reading IDCODE
BOOLEAN read_data[32];
BOOLEAN I_IDCODE[10] = BIN 1001101000; ‘assumed
BOOLEAN ONES_DATA[32] = HEX FFFFFFFF;
INTEGER i;
‘Set up stop state for IRSCAN
IRSTOP IRPAUSE;
‘Initialize device
STATE RESET;
IRSCAN 10, I_IDCODE[0..9]; ‘LOAD IDCODE INSTRUCTION
STATE IDLE;
WAIT 5 USEC, 3 CYCLES;
DRSCAN 32, ONES_DATA[0..31], CAPTURE
read_data[0..31];
‘CAPTURE IDCODE
PRINT “IDCODE:”;
FOR i=0 to 31;
PRINT read_data[i];
NEXT i;
EXIT 0;
11–50
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Configuring
Using the
MicroBlaster
Driver
The MicroBlasterTM software driver allows you to configure Altera
devices in an embedded environment using PS or FPP mode. The
MicroBlaster software driver supports a Raw Binary File (.rbf)
programming input file. The source code is developed for the Windows
NT operating system, although you can customize it to run on other
operating systems. For more information on the MicroBlaster software
driver, go to the Altera web site (www.altera.com).
Device
Configuration
Pins
The following tables describe the connections and functionality of all the
configuration related pins on the Stratix or Stratix GX device. Table 11–15
describes the dedicated configuration pins, which are required to be
connected properly on your board for successful configuration. Some of
these pins may not be required for your configuration schemes.
Table 11–15. Dedicated Configuration Pins on the Stratix or Stratix GX Device
Pin Name
VCCSEL
User Mode
N/A
Configuration
Scheme
All
Pin Type
Input
(Part 1 of 8)
Description
Dedicated input that selects which input buffer
is used on the configuration input pins;
nCONFIG, DCLK, RUnLU, nCE, nWS, nRS, CS,
nCS and CLKUSR.
The VCCSEL input buffer is powered by
VC C I N T and has an internal 2.5 kΩ pull-down
resistor that is always active.
A logic high (1.5-V, 1.8-V, 2.5-V, 3.3-V) selects
the 1.8-V/1.5-V input buffer, and a logic low
selects the 3.3-V/2.5-V input buffer. See the
“VCCSEL Pins” section for more details.
PORSEL
N/A
All
Input
Dedicated input which selects between a POR
time of 2 ms or 100 ms. A logic high (1.5-V, 1.8V, 2.5-V, 3.3-V) selects a POR time of about 2
ms and a logic low selects POR time of about
100 ms.
The PORSEL input buffer is powered by
VC C I N T and has an internal 2.5 kΩ pull-down
resistor that is always active.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Device Configuration Pins
Table 11–15. Dedicated Configuration Pins on the Stratix or Stratix GX Device
Pin Name
nIO_PULLUP
User Mode
N/A
Configuration
Scheme
All
Pin Type
Input
(Part 2 of 8)
Description
Dedicated input that chooses whether the
internal pull-ups on the user I/Os and dualpurpose I/Os (DATA[7..0], nWS, nRS,
RDYnBSY, nCS, CS, RUnLU, PGM[], CLKUSR,
INIT_DONE, DEV_OE, DEV_CLR) are on or
off before and during configuration. A logic high
(1.5-V, 1.8-V, 2.5-V, 3.3-V) turns off the weak
internal pull-ups, while a logic low turns them
on.
The nIO_PULLUP input buffer is powered by
VC C I N T and has an internal 2.5 kΩ pull-down
resistor that is always active.
MSEL[2..0]
N/A
All
Input
3-bit configuration input that sets the Stratix or
Stratix GX device configuration scheme. See
Table 11–2 for the appropriate connections.
These pins can be connected to VC C I O of the
I/O bank they reside in or ground. This pin uses
Schmitt trigger input buffers.
nCONFIG
N/A
All
Input
Configuration control input. Pulling this pin low
during user-mode causes the FPGA to lose its
configuration data, enter a reset state, tri-state
all I/O pins. Returning this pin to a logic high
level initiates a reconfiguration.
If your configuration scheme uses an
enhanced configuration device or EPC2
device, nCONFIG can be tied directly to VC C or
to the configuration device’s nINIT_CONF
pin. This pin uses Schmitt trigger input buffers.
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Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Table 11–15. Dedicated Configuration Pins on the Stratix or Stratix GX Device
Pin Name
nSTATUS
User Mode
N/A
Configuration
Scheme
All
Pin Type
(Part 3 of 8)
Description
Bidirectional The device drives nSTATUS low immediately
open-drain
after power-up and releases it after the POR
time.
Status output. If an error occurs during
configuration, nSTATUS is pulled low by the
target device. Status input. If an external
source drives the nSTATUS pin low during
configuration or initialization, the target device
enters an error state.
Driving nSTATUS low after configuration and
initialization does not affect the configured
device. If a configuration device is used, driving
nSTATUS low causes the configuration device
to attempt to configure the FPGA, but since the
FPGA ignores transitions on nSTATUS in usermode, the FPGA does not reconfigure. To
initiate a reconfiguration, nCONFIG must be
pulled low.
The enhanced configuration devices’ and
EPC2 devices’ OE and nCS pins have optional
internal programmable pull-up resistors. If
internal pull-up resistors on the enhanced
configuration device are used, external 10-kΩ
pull-up resistors should not be used on these
pins. When using EPC2 devices, only external
10-kΩ pull-up resistors should be used.
This pin uses Schmitt trigger input buffers.
Altera Corporation
July 2005
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Stratix Device Handbook, Volume 2
Device Configuration Pins
Table 11–15. Dedicated Configuration Pins on the Stratix or Stratix GX Device
Pin Name
CONF_DONE
User Mode
N/A
Configuration
Scheme
All
Pin Type
(Part 4 of 8)
Description
Bidirectional Status output. The target FPGA drives the
open-drain
CONF_DONE pin low before and during
configuration. Once all configuration data is
received without error and the initialization
cycle starts, the target device releases
CONF_DONE.
Status input. After all data is received and
CONF_DONE goes high, the target device
initializes and enters user mode. The
CONF_DONE pin must have an external
10-kΩ pull-up resistor in order for the device to
initialize.
Driving CONF_DONE low after configuration
and initialization does not affect the configured
device.
The enhanced configuration devices’ and
EPC2 devices’ OE and nCS pins have optional
internal programmable pull-up resistors. If
internal pull-up resistors on the enhanced
configuration device are used, external 10-kΩ
pull-up resistors should not be used on these
pins. When using EPC2 devices, only external
10-kΩ pull-up resistors should be used.
This pin uses Schmitt trigger input buffers.
nCE
N/A
All
Input
Active-low chip enable. The nCE pin activates
the device with a low signal to allow
configuration. The nCE pin must be held low
during configuration, initialization, and user
mode. In single device configuration, it should
be tied low. In multi-device configuration, nCE
of the first device is tied low while its nCEO pin
is connected to nCE of the next device in the
chain.
The nCE pin must also be held low for
successful JTAG programming of the FPGA.
This pin uses Schmitt trigger input buffers.
11–54
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Altera Corporation
July 2005
Configuring Stratix & Stratix GX Devices
Table 11–15. Dedicated Configuration Pins on the Stratix or Stratix GX Device
Pin Name
nCEO
User Mode
N/A
Configuration
Scheme
All MultiDevice
Schemes
Pin Type
Output
(Part 5 of 8)
Description
Output that drives low when device
configuration is complete. In single device
configuration, this pin is left floating. In multidevice configuration, this pin feeds the next
device’s nCE pin. The nCEO of the last device
in the chain is left floating.
The voltage levels driven out by this pin are
dependent on the VC C I O of the I/O bank it
resides in.
DCLK
N/A
Synchronous
configuration
schemes
(PS, FPP)
Input
(PS, FPP)
In PS and FPP configuration, DCLK is the clock
input used to clock data from an external
source into the target device. Data is latched
into the FPGA on the rising edge of DCLK.
In PPA mode, DCLK should be tied high to VC C
to prevent this pin from floating.
After configuration, this pin is tri-stated. In
schemes that use a configuration device,
DCLK is driven low after configuration is done.
In schemes that use a control host, DCLK
should be driven either high or low, whichever
is more convenient. Toggling this pin after
configuration does not affect the configured
device. This pin uses Schmitt trigger input
buffers.
DATA0
I/O
PS, FPP, PPA Input
Data input. In serial configuration modes, bitwide configuration data is presented to the
target device on the DATA0 pin. The VI H and
VI L levels for this pin are dependent on the
VC C I O of the I/O bank that it resides in.
After configuration, DATA0 is available as a
user I/O and the state of this pin depends on
the Dual-Purpose Pin settings.
After configuration, EPC1 and EPC1441
devices tri-state this pin, while enhanced
configuration and EPC2 devices drive this pin
high.
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Device Configuration Pins
Table 11–15. Dedicated Configuration Pins on the Stratix or Stratix GX Device
Pin Name
DATA[7..1]
User Mode
I/O
Configuration
Scheme
Parallel
configuration
schemes
(FPP and
PPA)
Pin Type
Inputs
(Part 6 of 8)
Description
Data inputs. Byte-wide configuration data is
presented to the target device on
DATA[7..0]. The VI H and VI L levels for
these pins are dependent on the VC C I O of the
I/O banks that they reside in.
In serial configuration schemes, they function
as user I/Os during configuration, which means
they are tri-stated.
After PPA or FPP configuration, DATA[7..1]
are available as a user I/Os and the state of
these pin depends on the Dual-Purpose Pin
settings.
DATA7
I/O
PPA
Bidirectional In the PPA configuration scheme, the DATA7
pin presents the RDYnBSY signal after the nRS
signal has been strobed low. The VI L and VI L
levels for this pin are dependent on the VC C I O
of the I/O bank that it resides in.
In serial configuration schemes, it functions as
a user I/O during configuration, which means it
is tri-stated.
After PPA configuration, DATA7 is available as
a user I/O and the state of this pin depends on
the Dual-Purpose Pin settings.
nWS
I/O
PPA
Input
Write strobe input. A low-to-high transition
causes the device to latch a byte of data on the
DATA[7..0] pins.
In non-PPA schemes, it functions as a user I/O
during configuration, which means it is tristated.
After PPA configuration, nWS is available as a
user I/O and the state of this pin depends on
the Dual-Purpose Pin settings.
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Configuring Stratix & Stratix GX Devices
Table 11–15. Dedicated Configuration Pins on the Stratix or Stratix GX Device
Pin Name
nRS
User Mode
I/O
Configuration
Scheme
PPA
Pin Type
Input
(Part 7 of 8)
Description
Read strobe input. A low input directs the
device to drive the RDYnBSY signal on the
DATA7 pin.
If the nRS pin is not used in PPA mode, it
should be tied high. In non-PPA schemes, it
functions as a user I/O during configuration,
which means it is tri-stated.
After PPA configuration, nRS is available as a
user I/O and the state of this pin depends on
the Dual-Purpose Pin settings.
RDYnBSY
I/O
PPA
Output
Ready output. A high output indicates that the
target device is ready to accept another data
byte. A low output indicates that the target
device is busy and not ready to receive another
data byte.
In PPA configuration schemes, this pin drives
out high after power-up, before configuration
and after configuration before entering usermode. In non-PPA schemes, it functions as a
user I/O during configuration, which means it is
tri-stated.
After PPA configuration, RDYnBSY is available
as a user I/O and the state of this pin depends
on the Dual-Purpose Pin settings.
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Device Configuration Pins
Table 11–15. Dedicated Configuration Pins on the Stratix or Stratix GX Device
Pin Name
nCS/CS
User Mode
I/O
Configuration
Scheme
PPA
Pin Type
Input
(Part 8 of 8)
Description
Chip-select inputs. A low on nCS and a high on
CS select the target device for configuration.
The nCS and CS pins must be held active
during configuration and initialization.
During the PPA configuration mode, it is only
required to use either the nCS or CS pin.
Therefore, if only one chip-select input is used,
the other must be tied to the active state. For
example, nCS can be tied to GND while CS is
toggled to control configuration.In non-PPA
schemes, it functions as a user I/O during
configuration, which means it is tri-stated.
After PPA configuration, nCS and CS are
available as a user I/Os and the state of these
pins depends on the Dual-Purpose Pin
settings.
RUnLU
N/A if using
Remote
Configuration;
I/O if not
Remote
Configuration
in FPP, PS or
PPA
Input
Input that selects between remote update and
local update. A logic high (1.5-V, 1.8-V, 2.5-V,
3.3-V) selects remote update and a logic low
selects local update.
When not using remote update or local update
configuration modes, this pins is available as
general-purpose user I/O pin.
PGM[2..0]
N/A if using
Remote
Configuration;
I/O if not using
Remote
Configuration
in FPP, PS or
PPA
Input
These output pins select one of eight pages in
the memory (either flash or enhanced
configuration device) when using a remote
configuration mode.
When not using remote update or local update
configuration modes, these pins are available
as general-purpose user I/O pins.
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Configuring Stratix & Stratix GX Devices
Table 11–16 describes the optional configuration pins. If these optional
configuration pins are not enabled in the Quartus II software, they are
available as general-purpose user I/O pins. Therefore during
configuration, these pins function as user I/O pins and are tri-stated with
weak pull-ups.
Table 11–16. Optional Configuration Pins
Pin Name
User Mode
Pin Type
Description
CLKUSR
N/A if option is
on. I/O if option
is off.
Input
Optional user-supplied clock input. Synchronizes the
initialization of one or more devices. This pin is enabled by
turning on the Enable user-supplied start-up clock
(CLKUSR) option in the Quartus II software.
INIT_DONE
N/A if option is
on. I/O if option
is off.
Output opendrain
Status pin. Can be used to indicate when the device has
initialized and is in user mode. When nCONFIG is low and
during the beginning of configuration, the INIT_DONE pin is
tri-stated and pulled high due to an external 10-kΩ pull-up.
Once the option bit to enable INIT_DONE is programmed
into the device (during the first frame of configuration data),
the INIT_DONE pin goes low. When initialization is
complete, the INIT_DONE pin is released and pulled high
and the FPGA enters user mode. Thus, the monitoring
circuitry must be able to detect a low-to-high transition. This
pin is enabled by turning on the Enable INIT_DONE output
option in the Quartus II software.
DEV_OE
N/A if option is
on. I/O if option
is off.
Input
Optional pin that allows the user to override all tri-states on
the device. When this pin is driven low, all I/Os are tri-stated.
When this pin is driven high, all I/Os behave as programmed.
This pin is enabled by turning on the Enable device-wide
output enable (DEV_OE) option in the Quartus II software.
DEV_CLRn
N/A if option is
on. I/O if option
is off.
Input
Optional pin that allows you to override all clears on all
device registers. When this pin is driven low, all registers are
cleared. When this pin is driven high, all registers behave as
programmed. This pin is enabled by turning on the Enable
device-wide reset (DEV_CLRn) option in the Quartus II
software.
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Device Configuration Pins
Table 11–17 describes the dedicated JTAG pins. JTAG pins must be kept
stable before and during configuration to prevent accidental loading of
JTAG instructions. If you plan to use the SignalTap II Embedded Logic
Analyzer, you will need to connect the JTAG pins of your device to a
JTAG header on your board.
Table 11–17. Dedicated JTAG pins
Pin Name
User Mode
Pin Type
Description
TDI
N/A
Input
Serial input pin for instructions as well as test and
programming data. Data is shifted in on the rising edge of
TCK. If the JTAG interface is not required on the board, the
JTAG circuitry can be disabled by connecting this pin to
VC C . This pin uses Schmitt trigger input buffers.
TDO
N/A
Output
Serial data output pin for instructions as well as test and
programming data. Data is shifted out on the falling edge
of TCK. The pin is tri-stated if data is not being shifted out
of the device. If the JTAG interface is not required on the
board, the JTAG circuitry can be disabled by leaving this
pin unconnected.
TMS
N/A
Input
Input pin that provides the control signal to determine the
transitions of the TAP controller state machine. Transitions
within the state machine occur on the rising edge of TCK.
Therefore, TMS must be set up before the rising edge of
TCK. TMS is evaluated on the rising edge of TCK. If the
JTAG interface is not required on the board, the JTAG
circuitry can be disabled by connecting this pin to VC C .
This pin uses Schmitt trigger input buffers.
TCK
N/A
Input
The clock input to the BST circuitry. Some operations
occur at the rising edge, while others occur at the falling
edge. If the JTAG interface is not required on the board, the
JTAG circuitry can be disabled by connecting this pin to
GND. This pin uses Schmitt trigger input buffers.
TRST
N/A
Input
Active-low input to asynchronously reset the boundaryscan circuit. The TRST pin is optional according to IEEE
Std. 1149.1. If the JTAG interface is not required on the
board, the JTAG circuitry can be disabled by connecting
this pin to GND. This pin uses Schmitt trigger input buffers.
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July 2005
12. Remote System
Configuration with Stratix &
Stratix GX Devices
S52015-3.1
Introduction
Altera® Stratix® and Stratix GX devices are the first programmable logic
devices (PLDs) featuring dedicated support for remote system
configuration. Using remote system configuration, a Stratix or Stratix GX
device can receive new configuration data from a remote source, update
the flash memory content (through enhanced configuration devices or
any other storage device), and then reconfigure itself with the new data.
Like all Altera SRAM-based devices, Stratix and Stratix GX devices
support standard configuration modes such as passive serial (PS), fast
passive parallel (FPP), and passive parallel asynchronous (PPA). You can
use the standard configuration modes with remote system configuration.
This chapter discusses remote system configuration of Stratix and Stratix
GX devices, and how to interface them with enhanced configuration
devices to enable this capability. This document also explains some
related remote system configuration topics, such as the watchdog timer,
remote system configuration registers, and factory or application
configurations files. The Quartus® II software (version 2.1 and later)
supports remote system configuration.
Remote
Configuration
Operation
Remote system configuration has three major parts:
■
The Stratix or Stratix GX device receives updated or new data from a
remote source over a network (or through any other source that can
transfer data). You can implement a Nios™ (16-bit ISA) or Nios® II
(32-bit ISA) embedded processor within either a Stratix or Stratix GX
device or an external processor to control the read and write
functions of configuration files from the remote source to the
memory device.
■
The new or updated information is stored into the memory device,
which can be an enhanced configuration device, industry-standard
flash memory device, or any other storage device (see Figure 12–2).
■
The Stratix or Stratix GX device updates itself with the new data from
the memory.
Figure 12–1 shows the concept of remote system configuration in Stratix
and Stratix GX devices.
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September 2004
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Remote Configuration Operation
Figure 12–1. Remote System Configuration with Stratix & Stratix GX Devices
Network
Data
Development
Location
Data
Data
Stratix or
Stratix GX
Device
Control Module
Memory
Stratix Device Configuration
Figure 12–2. Different Options for Remote System Configuration
External
Processor
Enhanced
Configuration
Device
MAX Device &
Flash Memory
Stratix or
Stratix GX
Device
Stratix or
Stratix GX
Device
Nios
Processor
Stratix or
Stratix GX
Device
Nios
Processor
Processor
MAX
Device
Enhanced
Configuration
Device
Flash
Memory
Flash
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Remote System Configuration with Stratix & Stratix GX Devices
Remote System Configuration Modes
Stratix and Stratix GX device remote system configuration has two
modes: remote configuration mode and local configuration mode.
Table 12–1 shows the pin selection settings for each configuration mode.
Table 12–1. Standard, Remote & Local Configuration Options Note (1)
RUnLU (2)
MSEL[2] (3)
MSEL[1..0]
System Configuration Mode
Configuration Mode
–
0
–
0
00
Standard
FPP
01
Standard
PPA
–
1
0
10
Standard
PS
1
00
Remote
FPP
1
1
01
Remote
PPA
1
1
10
Remote
PS
0
1
00
Local
FPP
0
1
01
Local
PPA
0
1
10
Local
PS
Notes to Table 12–1:
(1)
(2)
(3)
For detailed information on standard PS, FPP, and PPA models, see the Configuring Stratix & Stratix GX Devices
chapter of the Stratix Device Handbook, Volume 2.
In Stratix and Stratix GX devices, the RUnLU (remote update/local update) pin, selects between local or remote
configuration mode.
The MSEL[2] select mode selects between standard or remote system configuration mode.
Remote Configuration Mode
Using remote configuration mode, you can manage up to seven different
application configurations for Stratix and Stratix GX devices. The sevenconfiguration-file limit is due to the number of pages that the PGM[] pins
in the Stratix or Stratix GX device and enhanced configuration devices
can select.
1
If more than seven files are sent to a system using remote
configuration mode, previous files are overwritten.
Stratix and Stratix GX devices support remote configuration mode for PS,
FPP, and PPA modes. Specify remote configuration mode by setting the
MSEL2 and RUnLU pins to high. (See Table 12–1).
On power-up in remote configuration mode, the Stratix or Stratix GX
device loads the user-specified factory configuration file, located in the
default page address 000 in the enhanced configuration device. After the
device configures, the remote configuration control register points to the
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September 2004
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Remote Configuration Operation
page address of the application configuration that should be loaded into
the Stratix or Stratix GX device. If an error occurs during user mode of an
application configuration, the device reloads the default factory
configuration page. Figure 12–3 shows a diagram of remote configuration
mode.
Figure 12–3. Remote Configuration Mode
Power Up
Reconfigure
Configuration
Error
Factory
Configuration
Page (000)
Errors
Errors
Application 1
Configuration
PGM [001]
Reconfigure
Application 7
Configuration
PGM [111]
Local Configuration Mode
Local configuration mode—a simplified version of remote configuration
mode—is suitable for systems that load an application immediately upon
power-up. In this mode you can only use one application configuration,
which you can update either remotely or locally.
In local configuration mode, upon power-up, or when nCONFIG is
asserted, the Stratix or Stratix GX device loads the application
configuration immediately. Factory configuration loads only if an error
occurs during the application configuration’s user mode. If you use an
enhanced configuration device, page address 001 is the location for the
application configuration data, and page address 000 is the location for
the factory configuration data.
If the configuration data at page address 001 does not load correctly due
to cyclic redundancy code (CRC) failure, or it times-out of the enhanced
configuration device, or the external processor times-out, then the factory
configuration located at the default page (page address 000) loads into
the Stratix or Stratix GX device.
In local configuration mode (shown in Figure 12–4), the user watchdog
timer is disabled. For more information on the watchdog timer, see
“Watchdog Timer” on page 12–7.
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Remote System Configuration with Stratix & Stratix GX Devices
Figure 12–4. Local Configuration Mode
Power Up or
nCONFIG Assertion
Configuration Error
nCONFIG
Application
Configuration
PGM[001]
Factory
Configuration
PGM[000]
nCONFIG
Configuration
Error
In local configuration mode, one application configuration is available to
the device. For remote or local configuration mode selection, see
Table 12–1.
Remote System Configuration Components
The following components are used in Stratix and Stratix GX devices to
support remote and local configuration modes:
■
■
■
■
■
■
Page mode feature
Factory configuration
Application configuration
Watchdog timer
Remote update sub-block
Remote configuration registers
A description of each component follows.
Page Mode Feature
The page mode feature enables Stratix and Stratix GX devices to select a
location to read back data for configuration. The enhanced configuration
device can receive and store up to eight different configuration files (one
factory and seven application files). Selection of pages to read from is
performed through the PGM[2..0] pins on the Stratix or Stratix GX
device and enhanced configuration devices. These pins in the Stratix or
Stratix GX device can be designated user I/O pins during standard
configuration mode, but in remote system configuration mode, they are
dedicated output pins. Figure 12–5 shows the page mode feature in
Stratix or Stratix GX devices and enhanced configuration devices.
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September 2004
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Remote Configuration Operation
Figure 12–5. Page Mode Feature in Stratix or Stratix GX Devices & Enhanced
Configuration Devices
Enhanced Configuration
Device
POF 8
tix7
Stratix or
Stratix GX
Device
POF 1
Stratix 1
Page0
Page Select
Upon power-up in remote configuration mode, the factory configuration
(see description below) selects the user-specified page address through
the Stratix or Stratix GX PGM[2..0] output pins. These pins drive the
PGM[2..0] input pins of the enhanced configuration device and select
the requested page in the memory.
If an intelligent host is used instead of an enhanced configuration device,
you should create logic in the intelligent host to support page mode
settings similar to that in enhanced configuration devices.
Factory Configuration
Factory configuration is the default configuration data setup. In enhanced
configuration devices, this default page address is 000. Factory
configuration data is written into the memory device only once by the
system manufacturer and should not be remotely updated or altered. In
remote configuration mode, the factory configuration loads into the
Stratix or Stratix GX device upon power-up.
The factory configuration specifications are as follows:
■
■
■
■
■
Receives new configuration data and writes it to the enhanced
configuration or other memory devices
Determines the page address for the next application configuration
that should be loaded to the Stratix or Stratix GX device
Upon an error in the application configuration, the system reverts to
the factory configuration
Determines the reason for any application configuration error
Determines whether to enable or disable the user watchdog timer for
application configurations
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Remote System Configuration with Stratix & Stratix GX Devices
■
■
Determines the user watchdog timer’s settings if the timer is enabled
(remote configuration mode)
If the user watchdog timer is not reset after a predetermined amount
of time, it times-out and the system loads the factory configuration
data back to the Stratix or Stratix GX device
If a system encounters an error while loading application configuration
data, or if the device re-configures due to nCONFIG assertion, the Stratix
or Stratix GX device loads the factory configuration. The remote system
configuration register determines the reason for factory re-configuration.
Based on this information, the factory configuration determines which
application configuration needs to be loaded.
Application Configuration
The application configuration is the configuration data received from the
remote source and updated into different locations or pages of the
memory storage device (excluding the factory default page).
Watchdog Timer
A watchdog timer is a circuit that determines whether another
mechanism functions properly. The watchdog timer functions like a timedelay relay that remains in the reset state while an application runs
properly. This action periodically sends a reset command from the
working application to the watchdog timer. Stratix and Stratix GX
devices are equipped with a built-in watchdog timer for remote system
configuration.
A user watchdog timer prevents a faulty application configuration from
indefinitely stalling the Stratix or Stratix GX device. The timer functions
as a counter that counts down from an initial value, which is loaded into
the device from the factory configuration. This is a 29-bit counter, but you
use only the upper 12 bits to set the value for the watchdog timer. You
specify the counter value according to your design needs.
The timer begins counting once the Stratix or Stratix GX device goes into
user mode. If the application configuration does not reset the user
watchdog timer after the specified time, the timer times-out. At this point,
the Stratix or Stratix GX device is re-configured by loading the factory
configuration and resetting the user watchdog timer.
1
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September 2004
The watchdog timer is disabled in local configuration mode.
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Remote Configuration Operation
Remote Update Sub-Block
The remote update sub-block is responsible for administrating the remote
configuration feature. This sub-block, which is controlled by a remote
configuration state machine, generates the control signals required to
control different remote configuration registers.
Remote Configuration Registers
Remote configuration registers are a series of registers required to keep
track of page addresses and the cause of configuration errors. Table 12–2
gives descriptions of the registers’ functions. You can control both the
update and shift registers; the status and control registers are controlled
by internal logic, but can be read via the shift register.
Table 12–2. Remote Configuration Registers
Register
Description
Control register
This register contains the current page address, the watchdog timer setting, and
one bit specifying if the current configuration is a factory or application
configuration. During a capture in an application configuration, this register is
read into the shift register.
Update register
This register contains the same data as the control register, except that it is
updated by the factory configuration. The factory configuration updates the
register with the values to be used in the control register on the next reconfiguration. During capture in a factory configuration, this register is read into
the shift register.
Shift register
This register is accessible by the core logic and allows the update, status, and
control registers to be written and sampled by the user logic. The update register
can only be updated by the factory configuration in remote configuration mode.
Status register
This register is written into by the remote configuration block on every reconfiguration to record the cause of the re-configuration. This information is used
by factory configuration to determine the appropriate action following a reconfiguration.
Figure 12–6 shows the control, update, shift, and status registers and the
data path used to control remote system configuration.
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Remote System Configuration with Stratix & Stratix GX Devices
Figure 12–6. Remote Configuration Registers & Related Data Path
Status Register
Control Register
Bit4...Bit10
Bit16...Bit0
Logic
to Reconfig Logic
Update Register
Bit0...Bit16
User
Watchdog
Timer
Shift Register
Control Logic
RU_Dout
RU_shftnhld
RU_captnupdt
RU_Din
RU_clk
RU_Timer
RU_nCONFIG
Device Core
Table 12–3 describes the user configuration signals that are driven
to/from the device logic array. The remote configuration logic has one
input signal to the device logic array and six output signals from the
device logic array.
Table 12–3. User Configuration Signals To/From Device Core (Part 1 of 2)
Signal Name
To/From Device Core
Description
RU_Timer
Output from the core to the
remote update block
Request from the application to reset the user watchdog
timer with its initial count. A falling edge of this signal
triggers a reset of the user watchdog timer.
RU_nCONFIG
Output from the core to the
remote update block
When driven low, this signal triggers the device to
reconfigure. If requested by the factory configuration, the
application configuration specified in the remote update
control register is loaded. If requested by the application
configuration, the factory configuration is loaded.
RU_Clk
Output from the core to the
remote update block
Clocks the remote configuration shift register so that the
contents of the status and control registers can be read
out, and the contents of update register can be loaded.
The shift register latches data on the rising edge of the
RU_Clk.
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Table 12–3. User Configuration Signals To/From Device Core (Part 2 of 2)
Signal Name
To/From Device Core
Description
RU_shftnhld
Output from the core to the
remote update block
If its value is “1”, the remote configuration shift register
shifts data on the rising edge of RU_Clk. It its value is
“0” and RU_captnupdt is “0”, the shift register updates
the update register. If its value is “0”, and
RU_captnupdt is “1”, the shift register captures the
status register and either the control or update register
(depending on whether the configuration is factory or
application).
RU_captnupdt
Output from the core to the
remote update block
When RU_captnupdt is at value “1” and
RU_shftnhld is at value”0”, the system specifies that
the remote configuration shift register should be written
with the content of the status register and either the
update register (in a factory configuration) or the control
register (in an application configuration). This shift
register is loaded on the rising edge of RU_Clk. When
RU_captnupdt is at value “0” and RU_shftnhld is at
value”0”, the system specifies that the remote
configuration update register should be written with the
content of the shift register in a factory configuration. The
update register is loaded on the rising edge of RU_Clk.
This pin is enabled only for factory configuration in
remote configuration mode (it is disabled for the
application configuration in remote configuration or for
local configuration modes). If RU_shftnhld is at value
“1”, RU_captnupdt has no function.
RU_Din
Output from the core to the
remote update block
Data to be written into the remote configuration shift
register on the rising edge of RU_Clk. To load into the
shift register, RU_shftnhld must be asserted.
RU_Dout
Input to the core from the remote Output of the remote configuration shift register to be
update block
read by core logic. New data arrives on each rising edge
of RU_Clk.
All of the seven device core signals (see Figure 12–6), are enabled for both
remote and local configuration for both factory and application
configuration, except RU_Timer and RU_captnupdt. Figure 12–7 and
Table 12–4 specify the content of control register upon power-on reset
(POR).
The difference between local configuration and remote configuration is
how the control register is updated during a re-configuration and which
core signals are enabled.
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Remote System Configuration with Stratix & Stratix GX Devices
Figure 12–7. Remote System Configuration Control Register
Table 12–4 shows the content of the control register upon POR.
Table 12–4. Control Register Contents
Parameter
Definition
POR Reset Value
Comment
AnF
Current configuration is factory or
applications
1 bit ‘1’
Applications
1 bit ‘0’
Factory
PGM[2..0]
Page mode selection
3 bits ‘001’
Local configuration
3 bits ‘000’
Remote configuration
Wd_en
User watchdog timer enable
1 bit ‘0’
–
Wd_timer
[11..0]
User watchdog timer time-out value 12 bits ‘0’
High order bits of 29 bit counter
The status register specifies the reason why re-configuration has occurred
and determines if the re-configuration was due to a CRC error, nSTATUS
pulled low due to an error, the device core caused an error, nCONFIG was
reset, or the watchdog timer timed-out. Figure 12–8 and Table 12–5
specify the content of the status register.
Figure 12–8. Remote System Configuration Status Register
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September 2004
4
3
2
1
0
Wd
nCONFIG
CORE
nSTATUS
CRC
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Quartus II Software Support
Table 12–5 shows the content of the status register upon POR.
Table 12–5. Status Register Contents
Parameter
CRC (from
configuration)
POR Reset
Value
Definition
1 bit ‘0’
CRC caused re-configuration
nSTATUS
nSTATUS caused re-configuration
1 bit ‘0’
CORE (1)
Device core caused re-configuration
1 bit ‘0’
nCONFIG
NCONFIG caused re-configuration
1 bit ‘0’
Wd
Watchdog Timer caused re-configuration
1 bit ‘0’
Note to Table 12–5:
(1)
Quartus II
Software
Support
Core re-configuration enforces the system to load the application configuration
data into the Stratix or Stratix GX device. This occurs after factory configuration
specifies the appropriate application configuration data.
The Quartus II software supports implementation of both remote and
local configuration modes in your Stratix or Stratix II device. To include
the remote or local configuration feature to your design, select remote or
local as the configuration mode under the Device & Pin Options
compiler settings (prior to compilation). This selection reserves the dualpurpose RUnLU and PGM[2:0] pins for use as dedicated inputs in
remote/local configuration modes.
To set the configuration mode as remote or local, follow these steps (See
Figure 12–9):
1.
Open the Device & Pin Options settings window under the
Assignments menu.
2.
Select Device & Pin Options dialog box. The Device & Pin Options
dialog box is displayed.
3.
Click the Configuration tab.
4.
In the Configuration mode list, select Remote or Local.
The Standard mode selection disables the remote system configuration
feature. In addition to the mode selection, you can specify the
configuration scheme and configuration device (if any) used by your
setup.
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Remote System Configuration with Stratix & Stratix GX Devices
Figure 12–9. Device & Pin Options Dialog Box
Additionally, the remote configuration mode requires you to either
instantiate the altremote_update megafunction or the WYSIWYG
(what-you-see-is-what-you-get) atom into your design. Without this
atom or megafunction, you are not be able to access the dedicated remote
configuration circuitry or registers within the Stratix or Stratix GX device.
See Figure 12–10 for a symbol of the altremote_update megafunction.
The local configuration mode, however, can be enabled with only the
device Configuration Options compiler setting.
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Quartus II Software Support
Figure 12–10. altremote_update Megafunction Symbol
altremote_update Megafunction
A remote update megafunction, altremote_update, is provided in the
Quartus II software to provide a memory-like interface to allow for easy
control of the remote update parameters. Tables 12–6 and 12–7 describe
the input and output ports available on the altremote_update
megafunction. Table 12–8 shows the param[2..0] bit settings.
Table 12–6. Input Ports of the altremote_update Megafunction
Source
(Part 1 of 2)
Port Name
Required
clock
Y
Logic Array Clock input to the altremote_update block. All operations are
performed with respects to the rising edge of this clock.
reset
Y
Logic Array Asynchronous reset, which is used to initialize the remote update
block. To ensure proper operation, the remote update block must be
reset before first accessing the remote update block. This signal is not
affected by the busy signal and will reset the remote update block
even if busy is logic high. This means that if the reset signal is driven
logic high during writing of a parameter, the parameter will not be
properly written to the remote update block.
reconfig
Y
Logic Array When driven logic high, reconfiguration of the device is initiated using
the current parameter settings in the remote update block. If busy is
asserted, this signal is ignored. This is to ensure all parameters are
completely written before reconfiguration begins.
reset_timer
N
Logic Array This signal is required if you are using the watchdog timer feature. A
logic high resets the internal watchdog timer. This signal is not
affected by the busy signal and can reset the timer even when the
remote update block is busy. If this port is left connected, the default
value is 0.
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Table 12–6. Input Ports of the altremote_update Megafunction
Source
(Part 2 of 2)
Port Name
Required
Description
read_param
N
Logic Array Once read_param is sampled as a logic high, the busy signal is
asserted. While the parameter is being read, the busy signal remains
asserted, and inputs on param[] are ignored. Once the busy signal
is deactivated, the next parameter can be read. If this port is left
unconnected, the default value is 0.
write_param
N
Logic Array This signal is required if you intend on writing parameters to the
remote update block. When driven logic high, the parameter specified
on the param[] port should be written to the remote update block
with the value on data_in[]. The number of valid bits on
data_in[] is dependent on the parameter type. This signal is
sampled on the rising edge of clock and should only be asserted for
one clock cycle to prevent the parameter from being re-read on
subsequent clock cycles. Once write_param is sampled as a logic
high, the busy signal is asserted. While the parameter is being
written, the busy signal remains asserted, and inputs on param[]
and data_in[] are ignored. Once the busy signal is deactivated,
the next parameter can be written. This signal is only valid when the
Current_Configuration parameter is factory since parameters
cannot be written in application configurations. If this port is left
unconnected, the default value is 0.
param[2..0]
N
Logic Array 3-bit bus that selects which parameter should be read or written. If this
port is left unconnected, the default value is 0.
data_in[11..0]
N
Logic Array This signal is required if you intend on writing parameters to the
remote update block 12-bit bus used when writing parameters, which
specifies the parameter value. The parameter value is requested
using the param[] input and by driving the write_param signal
logic high, at which point the busy signal goes logic high and the value
of the parameter is captured from this bus. For some parameters, not
all 12-bits will be used in which case only the least significant bits will
be used. This port is ignored if the Current_Configuration
parameter is set to an application configuration since writing of
parameters is only allowed in the factory configuration. If this port is
left unconnected, the default values is 0.
Note to Table 12–6:
(1)
Logic array source means that you can drive the port from internal logic or any general-purpose I/O pin.
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Table 12–7. Output Ports of the altremote_update Megafunction
Port Name
Required Destination
Description
busy
Y
Logic Array When this signal is a logic high, the remote update block is busy
either reading or writing a parameter. When the remote update block
is busy, it ignores its data_in[], param[], and reconfig
inputs. This signal will go high when read_param or
write_param is asserted and will remain asserted until the
operation is complete.
pgm_out[2..0]
Y
PGM[2..0]
pins
data_out[11..0]
N
Logic Array 12-bit bus used when reading parameters, which reads out the
parameter value. The parameter value is requested using the
param[] input and by driving the read_param signal logic high,
at which point the busy signal will go logic high. When the busy signal
goes low, the value of the parameter will be driven out on this bus.
The data_out[] port is only valid after a read_param has been
issued and once the busy signal is de-asserted. At any other time, its
output values are invalid. For example, even though the
data_out[] port may toggle during a writing of a parameter, these
values are not a valid representation of what was actually written to
the remote update block. For some parameters, not all 12-bits will be
used in which case only the least significant bits will be used.
3-bit bus that specifies the page pointer of the configuration data to
be loaded when the device is reconfigured. This port must be
connected to the PGM[] output pins, which should be connected to
the external configuration device
Note to Table 12–7:
(1)
Logic array destination means that you can drive the port to internal logic or any general-purpose I/O pin.
Table 12–8. Parameter Settings for the altremote_update Megafunction
(Part 1 of 2)
param[2..0]
bit setting
width of
parameter
value
POR Reset
Value
Status
Register
Contents
000
5
5 bit '0
Specifies the reason for re-configuration,
which could be caused by a CRC error during
configuration, nSTATUS being pulled low due
to an error, the device core caused an error,
nCONFIG pulled low, or the watchdog timer
timed-out. This parameter can only be read.
Watchdog
Timeout Value
010
12
12 bits '0
User watchdog timer time-out value. Writing of
this parameter is only allowed when in the
factory configuration.
Watchdog
Enable
011
1
1 bit '0
User watchdog timer enable. Writing of this
parameter is only allowed when in the factory
configuration
Selected
Parameter
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Table 12–8. Parameter Settings for the altremote_update Megafunction
(Part 2 of 2)
param[2..0]
bit setting
width of
parameter
value
Page select
100
3
3 bit '001' - Local Page mode selection. Writing of this parameter
configuration
is only allowed when in the factory
configuration.
3 bit '000' Remote
configuration
Current
configuration
(AnF)
101
1
1 bit '0' - Factory Specifies whether the current configuration is
factory or and application configuration. This
1 bit '1' parameter can only be read.
Application
Illegal values
001
Selected
Parameter
POR Reset
Value
Description
110
111
Remote Update WYSIWYG ATOM
An alternative to using the altremote_update megafunction is to
directly instantiate the remote update WYSIWYG atom. This atom should
be included in the factory configuration and any application
configuration image to access the remote configuration shift registers.
When implementing the atom, you should consider following:
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September 2004
1.
Only one atom can be used in the circuit; more than one gives a
no-fit.
2.
All signals for the cell must be connected. The clock port (CLK) must
be connected to a live cell. The others can be constant VCC or GND.
3.
The pgmout port must be connected and must feed PGM[2.0]
output pins (it cannot be connected to anything else but output
pins).
4.
The Quartus II software reserves RUnLU as an input pin, and you
must connect it to VCC.
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The Stratix and Stratix GX remote update atom ports are:
Stratix_rublock <rublock_name>
(
.clk(<clock source>),
.shiftnld(<shiftnld source>),
.captnupdt(<shiftnld source>),
.regin(<regin input source from the core>),
.rsttimer(<input signal to reset the watchdog timer>),
.config(<input signal to initiate configuration>),
.regout(<data output destination to core>),
.pgmout(<program output destinations to pins>)
Table 12–9 shows the remote update block input and output port names
and descriptions.
Table 12–9. Remote Update Block Input & Output Ports
Ports
Definition
<rublock_name>
The unique identifier for the instance. This identifier name can be anything as
long as it is legal for the given description language (i.e., Verilog, VHDL, AHDL,
etc.). This field is required.
.clk(<clock source>)
Designates the clock input of this cell. All operation is with respect to the rising
edge of this clock. This field is required.
.shiftnld(<shiftnld source>)
An input into the remote configuration block. When .shiftnld = 1, the data shifts
from the internal shift registers to the regout port at each rising edge of clk,
and the data also shifts into the internal shift registers from regin port. This field
is required.
.captnupdt(<shiftnld
source>)
An input into the remote configuration block. This controls the protocol of when
to read the configuration mode or when to write into the registers that control the
configuration. This field is required.
.regin(<regin input source
from the core>)
An input into the configuration block for all data loading into the core. The data
shifts into the internal registers at the rising edge of clk. This field is required.
.rsttimer(<input signal to
reset the watchdog timer>)
An input into the watchdog timer of the remote update block. When this is high, it
resets the watchdog timer. This field is required.
.config(<input signal to
initiate configuration>)
An input into the configuration section of the remote update block. When this
signal goes high, the part initiates a re-configuration. This field is required.
.regout(<data output
destination to core>)
A 1-bit output, which is the output of the internal shift register, and updated every
rising edge of clk. The data coming out depends on the control signals. This
field is required.
.pgmout(<program output
destinations to pins>)
A 3-bit bus. It should always be connected only to output pins (not bidir pins).
This bus gives the page address (000 to 111) of the configuration data to be
loaded when the device is getting configured. This field is required.
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f
Using Enhanced
Configuration
Devices
For more information on the control signals for the remote block, see
Table 12–3 on page 12–9.
This section describes remote system configuration of Stratix and
Stratix GX devices with the Nios embedded processor using enhanced
configuration devices. Enhanced configuration devices are composed of
a standard flash memory and a controller. The flash memory stores
configuration data, and the controller reads and writes to the flash
memory.
In remote system configuration, only PS and FPP modes are supported
using an enhanced configuration device. A Stratix or Stratix GX device
running a Nios embedded processor can receive data from a remote
source through a network or any other appropriate media. A specific
page of the enhanced configuration device stores the received data.
This scheme uses the page mode option in Stratix and Strati GX devices.
Up to eight pages can be stored in each enhanced configuration device,
each of which can store a configuration file.
In enhanced configuration devices, a page is a section of the flash
memory space. Its boundary is determined by the Quartus II software
(the page size is programmable). In the software, you can specify which
configuration file should be stored in which page within the flash
memory. To access the configuration file on each page, set the three input
pins (PGM[2..0]), which provide access to all eight pages. Because the
PGM[2..0] pins of an enhanced configuration device connect to the
same pins of the Stratix or Stratix GX device, the Stratix or Stratix GX
device selects one of the eight memory pages as a target location to read
from. Figure 12–11 shows the allocation of different pages in the
enhanced configuration device.
f
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For more information on enhanced configuration devices, see the
Enhanced Configuration Devices (EPC4, EPC8 & EPC16) Data Sheet and the
Altera Enhanced Configuration Devices chapter.
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Figure 12–11. Memory Map in Enhanced Configuration Device
Enhanced Configuration Devices
Processor
Space
Unused Memory
Page7
Configuration
Space
Page1
Page0
Option Bits
Boot & Parameter Block
When the Stratix or Stratix GX device powers-up in remote configuration
mode, the devices loads configuration data located at page address 000.
You should always load the factory default configuration data at this
location and make sure this information is not altered.
The factory configuration contains information to determine the next
application configuration to load into the Stratix or Stratix GX device.
When the Stratix or Stratix GX device successfully loads the application
configuration from the page selected by the PGM[2..0] pins, it enters
user mode.
In user mode, the Nios embedded processor (or any other logic) assists
the Stratix or Stratix GX device in detecting remote system configuration
information. In remote system configuration, the Nios embedded
processor receives the incoming data from the remote source via the
network, writes it to the ECP16 enhanced configuration device, and then
initiates loading of the factory configuration into the Stratix or Stratix GX
device. Factory configuration reads the remote configuration status
register and determines the appropriate application configuration to load
into the Stratix or Stratix GX device. Figure 12–12 shows the remote
system configuration.
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Figure 12–12. Remote System Configuration Using Enhanced Configuration Devices
Stratix or
Stratix GX Device
Application
Configuration Data
Remote Source
Application
Configuration Data
Enhanced
Configuration Device
Application Data 1
Nios
Processor
PGM[2..0]
Application/Factory
Configuration Data
(Network)
Watchdog
Circuitry
Application Data 7
Configuration
Control Signals
Factory Data
Selecting Next
Application from
Factory Data
The user watchdog timer in Stratix and Stratix GX devices ensures that an
application configuration has loaded successfully and checks if the
application configuration is operating correctly in user mode. The
watchdog timer must be continually reset by the user logic. If an error
occurs while the application configuration loads, or if the watchdog timer
times-out during user mode, the factory configuration is reloaded to
prevent the system from halting in an erroneous state. Figure 12–3 on
page 12–4 illustrates the remote configuration mode.
Upon power-up in local configuration scheme, the application
configuration at page 001 (PGM[001] of the enhanced configuration
device) loads into the Stratix or Stratix GX device. This application can be
remotely or locally updated. If an error occurs during loading of the
configuration data, the factory configuration loads automatically (see
Figure 12–4 on page 12–5). The rest is identical to remote configuration
mode.
Local Update Programming File Generation
This section describes the programming file generation process for
performing remote system upgrades. The Quartus II convert
programming files (CPF) utility generates the initial and partial
programming files for configuration memory within the enhanced
configuration devices.
The two pages that local configuration mode uses are a factory
configuration stored at page 000, and an application configuration stored
at page 001. The factory configuration cannot be updated after initial
production programming. However, the application configuration can be
erased and reprogrammed after initial system deployment.
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In local update mode, you would first create the initial programming file
with the factory configuration image and a version of the application
configuration. Subsequently, you can generate partial programming files
to update the application configuration (stored in page 001). Quartus II
CPF can create partial programming files in .hex (Hexadecimal file), JAM,
.jbc (JAM Byte-Code File), and POF formats.
In addition to the two configuration pages, user data or processor code
can also be pre-programmed in the bottom boot and main data areas of
the enhanced configuration device memory. The CPF utility accepts a
HEX input file for the bottom and main data areas, and includes this data
in the POF output file. However, this is only supported for initial
programming file generation. Partial programming file generation for
updating user HEX data is not supported, but can be performed using the
enhanced configuration device external flash interface.
Initial Programming File Generation
The initial programming file includes configuration data for both factory
and application configuration pages. The enhanced configuration device
option’s bits are always located between byte addresses 0x00010000
and 0x0001003F. Also, page 0 always starts at 0x00010040 while its
end address is dependent on the size of the factory configuration data.
The two memory allocation options that exist for the application
configuration are auto addressing and block addressing. In auto
addressing mode, Quartus II automatically allocates memory for the
application configuration. All the configuration memory sectors that are
not used by the page 0 factory configuration are allocated for page 1. The
memory allocated is maximized to allow future versions of the
application configuration to grow and have bigger configuration files
(when the compression feature is enabled). Processor or user data storage
(HEX input file) is only supported by the bottom boot area in auto
addressing mode.
The following steps and screen shot (see Figure 12–13) describe initial
programming file generation with auto addressing mode.
1.
Open the Convert Programming Files window from the File menu.
2.
Select Programmer Object File (*.pof) from the drop-down list
titled Programming File Type.
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September 2004
3.
Select the enhanced configuration device used (EPC4, EPC8,
EPC16), and the mode used (1-bit Passive Serial or Fast Passive
Parallel). Only during the initial programming file generation can
you specify the Options, Configuration Device, or Mode settings.
While generating the partial programming file, all of these settings
are grayed out and inaccessible.
4.
In the Input files to convert box, highlight SOF Data at Page 0 and
click Add File. Select input SOF file(s) for this configuration page
and insert them.
5.
Repeat Step 4 for the Page 1 application configuration page.
6.
Check the Memory Map File box to generate a memory map output
file that specifies the start/end addresses of each configuration page
and user data blocks.
7.
Save the CPF setup (optionally), by selecting Save Conversion
Setup… and specifying a name for the .cof output file.
8.
Click OK to generate initial programming and memory map files.
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Figure 12–13. CPF Setup for Initial Programming File (Auto Addressing)
A sample memory map output file for the preceding setup is shown
below. Configuration option bits and page 0 data occupy main flash
sectors 0 through 4. See the Sharp LHF16J06 Flash memory used in EPC16
devices Data Sheet at www.altera.com to correlate memory addresses to
the EPC16 flash sectors. In auto addressing mode, page 1 allocates all
unused flash sectors. For this example, this unused area includes main
sectors 5 through 30, and all of the bottom boot sectors. While this large
portion of memory is allocated for page 1, the real application
configuration data is top justified within this region with filler 1'b1 bits in
lower memory addresses. Notice that the page 1 configuration data
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wraps around the top of the memory and fills up the bottom boot area.
The wrap around does not occur if the bottom boot area is used for
processor/user HEX data file storage.
Block
Start Address
End Address
OPTION BITS 0x00010000
0x0001003F
PAGE 0
0x00010040
0x00054CC8
PAGE 1
0x001CB372
0x0000FFFD wrapped around
The block addressing mode allows better control of flash memory
allocation. You can allocate a specific flash memory region for each
application configuration page. This allocation is done by specifying a
block starting and block ending address. While selecting the size of the
region, you should account for growth in compressed configuration
bitstream sizes due to design changes and additions. In local update
mode, all configuration data is top justified within this allotted memory.
In other words, the last byte of configuration data is stored such that it
coincides with the highest byte address location within the allotted space.
Lower unused memory address locations within the allotted region are
filled with 1's. These filler bits are transmitted during a configuration
cycle using page 1, but are ignored by the Stratix device. The memory
map output file provides the exact byte address where real configuration
data for page 1 begins. Note that any partial update of page 1 should erase
all allotted flash sectors before storing new configuration data.
In the block addressing mode, HEX input files can be optionally added to
the bottom boot and main flash data areas (one HEX file per area is
allowed). The HEX file can be stored with relative addressing or absolute
addressing. For more information on relative and absolute addressing,
see the Using Altera Enhanced Configuration Devices chapter of the
Configuration Handbook.
Figures 12–14 and 12–15, and the following steps illustrate generating an
initial programming file with block addressing for local update mode.
This example also illustrates preloading user HEX data into bottom boot
and main flash sectors.
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September 2004
1.
Open the Convert Programming Files window from the File menu.
2.
Select Programmer Object File (.pof) from the drop-down list titled
Programming file type.
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3.
Select the enhanced configuration device (EPC4, EPC8, EPC16), and
the mode used (1-bit Passive Serial or Fast Passive Parallel). Only
during the initial programming file generation can you specify the
Options, Configuration device, or Mode settings. While generating
the partial programming file, all of these settings are grayed out and
inaccessible.
4.
In the Input files to convert box, highlight SOF Data at Page 0 and
click Add File. Select input SOF file(s) for this configuration page
and insert them.
5.
Repeat Step 4 for the Page 1 application configuration page.
6.
For enabling block addressing, select the SOF Data entry for Page 1,
and click Properties. This opens the SOF Data Properties dialog
box (see Figure 12–15).
7.
Pick Block from the Address Mode drop down selection, and enter
32-bit Hexadecimal byte address for block Starting Address and
Ending Address. Note that for partial programming support, the
block start and end addresses should be aligned to a flash sector
boundary. This prevents two configuration pages from overlapping
within the same flash boundary. See the flash memory datasheet for
data sector boundary information. Click OK to save SOF data
properties.
8.
Check the Memory Map File box to generate a memory map output
file that specifies the start/end addresses of each configuration page
and user data blocks.
9.
Save the CPF setup (optionally), by selecting Save Conversion
Setup… and specifying a name for the COF output file.
10. Click OK to generate initial programming and memory map files.
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Figure 12–14. CPF Setup for Initial Programming File Generation (Block Addressing)
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Figure 12–15. Specifying Block Addresses for Application Configuration
A sample memory map output file for the preceding example is shown
below. Note that the allocated memory for page 1 is between
0x00080000 and 0x001EFFFF, while the actual region used by the
current application configuration bitstream is between 0x001AB36C and
0x001EFFF7. The configuration data is top justified within the allocated
SOF data region.
Block
Start Address
End Address
BOTTOM BOOT
0x00000000
0x000001FF
OPTION BITS
0x00010000
0x0001003F
PAGE 0
0x00010040
0x00054CC8
PAGE 1
0x001AB36C
0x001EFFF7
TOP BOOT/MAIN
0x001F0000
0x001F01FF
Also note that the HEX data stored in the main data area uses absolute
addressing. If relative addressing were to be used, the main data contents
would be justified with the top (higher address locations) of the memory.
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The initial programming file (POF) can be converted to an Intel
Hexadecimal format file (*.HEXOUT) using the Quartus II CPF utility.
See Figure 12–16.
Figure 12–16. Converting POF Programming File to Intel HEX Format
Partial Programming File Generation
The enhanced Quartus II CPF utility allows an existing application
configuration page to be replaced with new data. Partial programming
files are generated to perform such configuration data updates.
In order to generate a partial programming file, you have to input the
initial programming file (POF) and new configuration data (SOF) to the
Quartus II CPF utility. In addition, you have to specify the addressing
mode (auto or manual) that was used during initial POF creation. And if
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block addressing was used, you should specify the block start and end
addresses. With this information, Quartus II ensures that the partial
programming file only updates the flash region containing the
application configuration. The factory configuration (page 0) and
configuration option bits are left unaltered during this process.
Figure 12–17 and the following steps illustrate generation of a partial
programming file:
1.
Open the Convert Programming Files window from the File menu.
2.
Select Programmer Object File for Local Update (.pof) from the
drop-down list titled Programming file type, and specify an output
File name.
3.
In the Input files to convert box, highlight POF Data and click Add
File. Select the initial programming POF file for this design and
insert it.
4.
In the Input files to convert box, highlight SOF Data and click Add
File. Select the new application configuration bitstream (SOF) and
insert it.
5.
When using block addressing, select the SOF Data entry for Page 1,
and click Properties. This opens the SOF Data Properties dialog
box (see Figure 12–18).
6.
Pick Block from the Address Mode drop down selection, and enter
32-bit Hexadecimal byte address for block Starting Address and
Ending Address. These addresses should be identical to those used
to generate the initial programming file. Click OK to save SOF data
properties.
7.
Check the Memory Map File box to generate a memory map output
file that specifies the start/end addresses of the new application
configuration data in page 1.
8.
Pick a local update difference file from the Remote/Local Update
Difference File drop-down menu. You can select between an Intel
HEX, JAM, JBC, and POF output file types. The output file name is
the same as the POF output file name with a _dif suffix.
9.
Save the CPF setup (optionally), by selecting Save Conversion
Setup… and specifying a name for the COF output file.
10. Click OK to generate initial programming and memory map files.
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Figure 12–17. Local Update Partial Programming File Generation
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Using Enhanced Configuration Devices
Figure 12–18. Specifying Block Addresses for Application Configuration
Remote Update Programming File Generation
This section describes the programming file generation process for
performing remote system upgrades. The Quartus II CPF utility
generates the initial and partial programming files for configuration
memory within the enhanced configuration devices.
Remote configuration mode uses a factory configuration stored at page 0,
and up to seven application configurations stored at pages 1 through 7.
The factory configuration cannot be updated after initial production
programming. However, the most recent application configuration can
be erased and reprogrammed after initial system deployment.
Alternatively, a new application configuration can be added provided
adequate configuration memory availability.
In remote update mode, you would first create the initial programming
file with the factory configuration image and the application
configuration(s). Subsequently, you can generate partial programming
files to update the most recent application configuration or add a new
application configuration. Quartus II CPF can create partial
programming files in HEX, JAM, JBC, and POF formats.
In addition to the configuration pages, user data or processor code can
also be pre-programmed in the bottom boot and main data areas of the
enhanced configuration device memory. The CPF utility accepts a HEX
input file for the bottom and main data areas, and includes this data in the
12–32
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Remote System Configuration with Stratix & Stratix GX Devices
POF output file. However, this is only supported for initial programming
file generation. Partial programming file generation for updating user
HEX data is not supported, but can be performed using the enhanced
configuration device external flash interface.
Initial Programming File Generation
The initial programming file includes configuration data for both factory
and application configuration pages. The enhanced configuration device
option’s bits are always located between byte addresses 0x00010000
and 0x0001003F. Also, page 0 always starts at 0x00010040 while its
end address is dependent on the size of the factory configuration data.
Two memory allocation options exist for application configurations: auto
addressing and block addressing. In auto addressing mode, Quartus II
packs all application configurations as close together as possible. This
maximizes the number of application configurations that can be stored in
memory. However, when auto addressing is used you cannot update
existing application configurations. Only new application configurations
can be added to the memory.
The following steps and screen shot (see Figure 12–19) describe initial
programming file generation with auto addressing mode.
Altera Corporation
September 2004
1.
Open the Convert Programming Files window from the File menu.
2.
Select Programmer Object File (*.pof) from the drop-down list
titled Programming file type.
3.
Select the enhanced configuration device used (EPC4, EPC8,
EPC16), and the mode used (1-bit Passive Serial or Fast Passive
Parallel). Only during the initial programming file generation can
you specify the Options, Configuration device, or Mode settings.
While generating the partial programming file, all of these settings
are grayed out and inaccessible.
4.
In the Input files to convert box, highlight SOF Data at Page 0 and
click Add File. Select input SOF file(s) for this configuration page
and insert them.
5.
Repeat Step 4 for all application configurations (up to 7 maximum).
6.
Check the Memory Map File box to generate a memory map output
file that specifies the start/end addresses of each configuration page
and user data blocks.
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Stratix Device Handbook, Volume 2
Using Enhanced Configuration Devices
7.
Save the CPF setup (optionally), by selecting Save Conversion
Setup… and specifying a name for the COF output file.
8.
Click OK to generate initial programming and memory map files.
Figure 12–19. CPF Setup for Initial Programming File Generation (Auto Addressing)
12–34
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Remote System Configuration with Stratix & Stratix GX Devices
A sample memory map output file for the preceding setup is shown
below. Notice all configuration pages are packed such that two pages can
share a flash data sector. This disallows partial programming of
application configurations in auto addressing mode.
Block
f
Start Address
End Address
OPTION BITS
0x00010000
0x0001003F
PAGE 0
0x00010040
0x00054EFA
PAGE 1
0x00054EFC
0x00099DB6
PAGE 2
0x00099DB8
0x000DEC72
See the Sharp LHF16J06 Data Sheet Flash memory used in EPC16 devices at
www.altera.com to correlate memory addresses to the EPC16 flash
sectors.
The block addressing mode allows better control of flash memory
allocation. You can allocate a specific flash memory region for each
application configuration page. This allocation is done by specifying a
block starting and block ending address. While selecting the size of the
region, you should account for growth in compressed configuration
bitstream sizes due to design changes and additions. In remote update
mode, all configuration data is top justified within this allotted memory.
In other words, the last byte of configuration data is stored such that it
coincides with the highest byte address location within the allotted space.
Lower unused memory address locations within the allotted region are
filled with 1's. These filler bits are transmitted during the application
configuration cycle, but are ignored by the Stratix device. The memory
map output file provides the exact byte address where real application
configuration data for each page begins. Note that any partial update of
the most recent application configuration should erase all allotted flash
sectors for that page before storing new configuration data.
In the block addressing mode, HEX input files can be optionally added to
the bottom boot and main flash data areas (one HEX file per area is
allowed). The HEX file can be stored with relative addressing or absolute
addressing. For more information on relative and absolute addressing,
see the Enhanced Configuration Devices (EPC4, EPC8 & EPC16) Data Sheet
chapter of the Configuration Handbook, Volume 2.
Figures 12–20 and 12–21, and the following steps illustrate generating an
initial programming file with block addressing for remote update mode.
This example also illustrates preloading user HEX data into bottom boot
and main flash sectors.
1.
Altera Corporation
September 2004
Open the Convert Programming Files window from the File menu.
12–35
Stratix Device Handbook, Volume 2
Using Enhanced Configuration Devices
2.
Select Programmer Object File (*.pof) from the drop-down list
titled Programming file type.
3.
Select the enhanced configuration device used (EPC4, EPC8,
EPC16), and the mode used (1-bit Passive Serial or Fast Passive
Parallel). Only during the initial programming file generation can
you specify the Options, Configuration device, or Mode settings.
While generating the partial programming file, all of these settings
are grayed out and inaccessible.
4.
In the Input files to convert box, highlight SOF Data at Page 0 and
click Add File. Select input SOF file(s) for this configuration page
and insert them.
5.
Repeat Step 4 for all the application configuration pages (pages 1
and 2 in this example).
6.
For enabling block addressing, select the SOF Data entry for Page 1,
and click Properties. This opens the SOF Data Properties dialog
box (see Figure 12–21).
7.
Pick Block from the Address Mode drop down selection, and enter
32-bit Hexadecimal byte address for block Starting Address and
Ending Address. Note that for partial programming support, the
block start and end addresses should be aligned to a flash sector
boundary. This prevents two configuration pages from overlapping
within the same flash boundary. See the flash memory datasheet for
data sector boundary information. Click OK to save SOF data
properties.
8.
Check the Memory Map File box to generate a memory map output
file that specifies the start/end addresses of each configuration page
and user data blocks.
9.
Save the CPF setup (optionally), by selecting Save Conversion
Setup… and specifying a name for the COF output file.
10. Click OK to generate initial programming and memory map files.
12–36
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Remote System Configuration with Stratix & Stratix GX Devices
Figure 12–20. CPF Setup for Initial Programming File Generation (Block Addressing)
Altera Corporation
September 2004
12–37
Stratix Device Handbook, Volume 2
Using Enhanced Configuration Devices
Figure 12–21. Specifying Block Addresses for an Application Configuration
A sample memory map output file for the preceding example is shown
below. Note that the allocated memory for page 1 is between
0x00070000 and 0x000BFFFF, while the actual region used by the
current application configuration bitstream is between 0x0007B144 and
0x000BFFFF. The configuration data is top justified within the allocated
SOF data region. Similarly, the allocated memory for page 2 is between
0x000D0000 and 0x0012FFFF, while the actual region used by the
application configuration is between 0x000EB13E and 0x0012FFF9.
Block
Start Address
End Address
BOTTOM BOOT
0x00000000
0x000001FF
OPTION BITS
0x00010000
0x0001003F
PAGE 0
0x00010040
0x00054EFA
PAGE 1
0x0007B144
0x000BFFFF
PAGE 2
0x000EB13E
0x0012FFF9
TOP BOOT/MAIN
0x001F0000
0x001F01FF
Also note that the HEX data stored in the main data area uses absolute
addressing. If relative addressing were to be used, the main data contents
would be justified with the top (higher address locations) of the memory.
The initial POF can be converted to an Intel Hexadecimal format file
(*.HEXOUT) using the Quartus II CPF utility. See Figure 12–22.
12–38
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Remote System Configuration with Stratix & Stratix GX Devices
Figure 12–22. Converting POF Programming File to Intel HEX Format
Partial Programming File Generation
In remote update mode, the Quartus II CPF utility allows an existing
application configuration page to be replaced with new data, or a new
application configuration to be added. Partial programming files are
generated to perform such configuration data updates.
In order to generate a partial programming file, you have to input the
initial POF and new configuration data (SOF) to the Quartus II CPF
utility. In addition, you have to specify the addressing mode (auto or
manual) that was used during initial POF creation. And if block
addressing was used, you should specify the block start and end
Altera Corporation
September 2004
12–39
Stratix Device Handbook, Volume 2
Using Enhanced Configuration Devices
addresses. With this information, Quartus II ensures that the partial POF
only updates the flash region containing the application configuration.
The factory configuration (page 0) and configuration option bits are left
unaltered during this process. The only exception is when a new
application configuration is added, the configuration options bits are
updated to include start/end addresses for the new page. All existing
page addresses and other configuration options bits remain unchanged.
Figure 12–23 and the following steps illustrate generation of a partial
programming file to replace the most recent application configuration. In
this example, the initial programming file contained one factory and two
application configurations. Hence, the page 2 application configuration is
being updated with new data.
1.
Open the Convert Programming Files window from the File menu.
2.
Select Programmer Object File for Remote Update (*.pof) from the
drop-down list titled Programming file type, and specify an output
file name.
3.
In the Input files to convert box, highlight POF Data and click Add
File. Select the initial programming POF file for this design and
insert it.
4.
In the Input files to convert box, highlight SOF Data and click Add
File. Select the new application configuration bitstream (SOF) and
insert it.
5.
When using block addressing, select the SOF Data entry for Page 2,
and click Properties. This opens the SOF Data Properties dialog
box (see Figure 12–24 on page 12–42).
6.
Pick Block from the Address Mode drop down selection, and enter
32-bit Hexadecimal byte address for block Starting Address and
Ending Address. These addresses should be identical to those used
to generate the initial programming file. Click OK to save SOF data
properties.
7.
Check the Memory Map File box to generate a memory map output
file that specifies the start/end addresses of the new application
configuration data in page 1.
8.
Pick a remote update difference file from the Remote/Local Update
Difference File drop-down menu. You can select between an Intel
HEX, JAM, JBC, and POF output file types. The output file name is
the same as the POF output file name with a _dif suffix.
12–40
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Remote System Configuration with Stratix & Stratix GX Devices
9.
Save the CPF setup (optionally), by selecting Save Conversion
Setup… and specifying a name for the COF output file.
10. Click OK to generate initial programming and memory map files.
Figure 12–23. Remote Update Partial Programming File Generation
Altera Corporation
September 2004
12–41
Stratix Device Handbook, Volume 2
Combining MAX Devices & Flash Memory
Figure 12–24. Specifying Block Addresses for Application Configuration
For adding a new application configuration, follow the steps listed above
with one modification. In Step 5, select SOF Data and click on Properties.
In the SOF Data Properties dialog box, select a new page (for example,
page 3) and specify the addressing mode information. Continue with
steps 7 through 10. When a new page is added, the memory map output
file lists the start/end addresses for this page. A sample is shown below:
Block
Combining MAX
Devices & Flash
Memory
Start Address
End Address
OPTION BITS
0x00010000
0x0001003F
PAGE 3
0x0012FFFA
0x00174EB4
This section describes remote system configuration with the Stratix or
Stratix GX device and the Nios embedded processor, using a combination
of MAX® devices and flash memory.
You can use MAX 3000 or MAX 7000 devices and an industry-standard
flash memory device instead of enhanced configuration devices. In this
scheme, flash memory stores configuration data, and the MAX device
controls reading and writing to the flash memory, keeping track of
address locations.
The MAX device determines which address location and at what length
to store configuration data in flash memory. The Nios embedded
processor, running in the Stratix or Stratix GX device, receives the
12–42
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Remote System Configuration with Stratix & Stratix GX Devices
incoming data from the remote source and writes it to the address
location in flash memory. The Nios embedded processor initiates loading
of factory configuration into the Stratix or Stratix GX device. Figure 12–25
shows remote system configuration using a MAX device and flash
memory combination.
Figure 12–25. Remote System Configuration Using a MAX Device & Flash Memory
Stratix or
Stratix GX Device
Application
Configuration Data
Remote Source
Nios
Processor
MAX & Flash Memory
Application/Factory
Configuration Data
MAX Device
Configuration
Control Signals
Flash Memory
Watchdog
Circuitry
Application Data 1
Application
Configuration Data
Application Data 7
Factory Data
Selecting Next
Application from
Factory Data
You can use both remote and local configuration modes in this scheme.
You should specify a default page for factory configuration and make
sure it is not altered or removed at any time. In remote system
configuration mode, PS, FPP, and PPA modes are supported when
configuring with MAX and flash devices.
Using an
External
Processor
This section describes remote system configuration with Stratix or Stratix
GX devices and the Nios embedded processor, using an external
processor and flash memory devices.
In this scheme, the external processor and flash memory device replace
the enhanced configuration device. Flash memory stores configuration
data, and the processor controls reading and writing to the flash memory
and also keeps track of the address location. This type of remote system
configuration supports PS, FPP, and PPA modes.
The processor determines at which address which length to store the
configuration data in flash memory. The Nios embedded processor
receives the incoming data from a remote source and writes it to the
address location in the flash memory, and then initiates loading of factory
Altera Corporation
September 2004
12–43
Stratix Device Handbook, Volume 2
Conclusion
configuration data into the Stratix or Stratix GX device. Figure 12–26
shows the remote system configuration using a Nios embedded
processor and flash memory.
You can use both remote and local configuration modes in this scheme.
You should specify a default page for factory configuration and make
sure it is not altered or removed at any time.
Figure 12–26. Remote System Configuration Using External Processor & Flash Memory
Stratix or
Stratix GX Device Application/Factory
Configuration Data
Application
Configuration Data
Remote Source
Nios
Processor
External Processor
& Flash Memory
External Processor
Configuration
Control Signals
Flash Memory
Watchdog
Circuitry
Application Data 1
Application
Configuration Data
Application Data 7
Factory Data
Selecting Next
Application from
Factory Data
Conclusion
Stratix and Stratix GX devices are the first PLDs with dedicated support
for remote system configuration. By allowing real-time system upgrades
from a remote source, you can use Stratix and Stratix GX devices in a
variety of applications that require automatic configuration updates.
With the built-in watchdog timer circuitry, Stratix and Stratix GX devices
avoid incorrect or erroneous states. Using Stratix and Stratix GX devices
with remote system configuration enhances design flexibility and
reduces time to market.
12–44
Stratix Device Handbook, Volume 2
Altera Corporation
September 2004
Section VII. PCB Layout
Guidelines
This section provides information for board layout designers to
successfully layout their boards for Stratix® devices. This section contains
the required PCB layout guidelines and package specifications.
This section contains the following chapters:
Revision History
Chapter
13
■
Chapter 13, Package Information for Stratix Devices
■
Chapter 14, Designing with 1.5-V Devices
The table below shows the revision history for Chapters 13 and 14.
Date/Version
July 2005, v3.0
Updated packaging information.
●
Changed from Chapter 8, Volume 3 to Chapter 13, Volume 2.
Corrected spelling error.
April 2003, v1.0
●
No new changes in Stratix Device Handbook v2.0.
January 2005, v1.2
●
This chapter was formerly chapter 15.
September 2004, v1.1
●
●
Changed from Chapter 10, Volume 3 to Chapter 15, Volume 2.
Corrected spelling error.
●
No new changes in Stratix Device Handbook v2.0.
September 2004, v2.1
14
Changes Made
April 2003, v1.0
Altera Corporation
●
Section VII–1
PCB Layout Guidelines
Section VII–2
Stratix Device Handbook, Volume 2
Altera Corporation
13. Package Information for
Stratix Devices
S53008-3.0
Introduction
This data sheet provides package information for Altera® devices. It
includes these sections:
Section
Page
Device & Package Cross Reference . . . . . . . . . . . . . . . . . . . . . 13–1
Thermal Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13–2
Package Outlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13–3
In this data sheet, packages are listed in order of ascending pin count.
Device &
Package Cross
Reference
Table 13–1 shows which Altera Stratix® devices are available in BGA,
FineLine BGA and Ultra FineLine BGA packages.
Table 13–1. Stratix Devices in BGA, FineLine BGA & Ultra FineLine BGA
Packages (Part 1 of 2)
Device
EP1S10
EP1S20
EP1S25
EP1S30
Package
Flip-chip FineLine BGA
484
BGA
672
FineLine BGA
672
Flip-chip FineLine BGA
780
Flip-chip FineLine BGA
484
BGA
672
FineLine BGA
672
Flip-chip FineLine BGA
780
BGA
672
FineLine BGA
672
Flip-chip FineLine BGA
780
Flip-chip FineLine BGA
1,020
Flip-chip FineLine BGA
780
Flip-chip BGA
956
Flip-chip FineLine BGA
Altera Corporation
July 2005
Pins
1,020
13–1
Thermal Resistance
Table 13–1. Stratix Devices in BGA, FineLine BGA & Ultra FineLine BGA
Packages (Part 2 of 2)
Device
Package
EP1S40
Pins
Flip-chip FineLine BGA
780
Flip-chip BGA
EP1S60
1,020
Flip-chip FineLine BGA
1,508
Flip-chip BGA
EP1S80
Thermal
Resistance
956
Flip-chip FineLine BGA
956
Flip-chip FineLine BGA
1,020
Flip-chip FineLine BGA
1,508
Flip-chip BGA
956
Flip-chip FineLine BGA
1,020
Flip-chip FineLine BGA
1,508
Table 13–2 provides θ JA (junction-to-ambient thermal resistance) and θJC
(junction-to-case thermal resistance) values for Altera Stratix devices.
Table 13–2. Thermal Resistance of Stratix Devices (Part 1 of 2)
θJC (° C/W)
θ JA (° C/W)
Still Air
θJA (° C/W)
100 ft./min.
θJA (° C/W)
200 ft./min.
θJA (° C/W)
400
ft./min.
FineLine
BGA
0.38
11.9
9.8
8.4
7.2
672
BGA
3.2
16.8
13.7
11.9
10.5
672
FineLine
BGA
3.4
17.2
14
12.2
10.8
780
FineLine
BGA
0.43
10.9
8.8
7.4
6.3
484
FineLine
BGA
0.30
11.8
9.7
8.3
7.1
Device
Pin Count
Package
EP1S10
484
EP1S20
672
BGA
2.5
15.5
12.4
10.7
9.3
672
FineLine
BGA
2.7
16
12.8
11
9.6
780
FineLine
BGA
0.31
10.7
8.6
7.2
6.1
13–2
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
Package Information for Stratix Devices
Table 13–2. Thermal Resistance of Stratix Devices (Part 2 of 2)
θJC (° C/W)
θ JA (° C/W)
Still Air
θJA (° C/W)
100 ft./min.
θJA (° C/W)
200 ft./min.
θJA (° C/W)
400
ft./min.
BGA
2.2
14.8
11.7
10.0
8.7
672
FineLine
BGA
2.3
15.3
12
10.4
9
780
FineLine
BGA
0.25
10.5
8.5
7.1
6.0
1020
FineLine
BGA
0.25
10.0
8.0
6.6
5.5
780
FineLine
BGA
0.2
10.4
8.4
7.0
5.9
Device
Pin Count
Package
EP1S25
672
EP1S30
EP1S40
EP1S60
EP1S80
956
BGA
0.2
9.1
7.1
5.8
4.8
1020
FineLine
BGA
0.2
9.9
7.9
6.5
5.4
780
FineLine
BGA
0.17
10.4
8.3
6.9
5.8
956
BGA
0.18
9.0
7.0
5.7
4.7
1020
FineLine
BGA
0.17
9.8
7.8
6.4
5.3
1508
FineLine
BGA
0.18
9.1
7.1
5.8
4.7
956
BGA
0.13
8.9
6.9
5.6
4.6
1020
FineLine
BGA
0.13
9.7
7.7
6.3
5.2
1508
FineLine
BGA
0.13
8.9
7.0
5.6
4.6
956
BGA
0.1
8.8
6.8
5.5
4.5
1020
FineLine
BGA
0.1
9.6
7.6
6.2
5.1
1508
FineLine
BGA
0.1
8.8
6.9
5.5
4.5
Package
Outlines
Altera Corporation
July 2005
The package outlines on the following pages are listed in order of
ascending pin count. Altera package outlines meet the requirements of
JEDEC Publication No. 95.
13–3
Stratix Device Handbook, Volume 2
Package Outlines
484-Pin FineLine BGA - Flip Chip
■
■
■
All dimensions and tolerances conform to ASME Y14.5M – 1994.
Controlling dimension is in millimeters.
Pin A1 may be indicated by an ID dot, or a special feature, in its
proximity on the package surface.
Tables 13–3 and 13–4 show the package information and package outline
figure references, respectively, for the 484-pin FineLine BGA packaging.
Table 13–3. 484-Pin FineLine BGA Package Information
Description
Specification
Ordering code reference
F
Package acronym
FineLine BGA
Substrate material
BT
Solder ball composition
Regular: 63Sn:37Pb (Typ.)
Pb-free: Sn:3Ag:0.5Cu (Typ.)
JEDEC outline reference
MS-034 variation: AAJ-1
Maximum lead coplanarity
0.008 inches (0.20 mm)
Weight
5.8 g
Moisture sensitivity level
Printed on moisture barrier bag
Table 13–4. 484-Pin FineLine BGA Package Outline Dimensions
Millimeter
Symbol
Min.
Nom.
Max.
A
–
–
3.50
A1
0.30
–
–
A2
0.25
–
3.00
A3
–
–
2.50
D
23.00 BSC
E
23.00 BSC
b
e
13–4
Stratix Device Handbook, Volume 2
0.50
0.60
0.70
1.00 BSC
Altera Corporation
July 2005
Package Information for Stratix Devices
Figure 13–1 shows a package outline for the 484-pin FineLine BGA
packaging.
Figure 13–1. 484-Pin FineLine BGA Package Outline
TOP VIEW
BOTTOM VIEW
Pin A1
Corner
D
Pin A1 ID
e
E
b
e
A
A2
A3
A1
Altera Corporation
July 2005
13–5
Stratix Device Handbook, Volume 2
Package Outlines
672-Pin FineLine BGA - Flip Chip
■
■
■
All dimensions and tolerances conform to ASME Y14.5M - 1994.
Controlling dimension is in millimeters.
Pin A1 may be indicated by an ID dot, or a special feature, in its
proximity on package surface.
Tables 13–5 and 13–6 show the package information and package outline
figure references, respectively, for the 672-pin FineLine BGA packaging.
Table 13–5. 672-Pin FineLine BGA Package Information
Description
Specification
Ordering code reference
F
Package acronym
FineLine BGA
Substrate material
BT
Solder ball composition
Regular: 63Sn:37Pb (Typ.)
Pb-free: Sn:3Ag:0.5Cu (Typ.)
JEDEC Outline Reference
MS-034
Maximum lead coplanarity
0.008 inches (0.20 mm)
Weight
7.7 g
Moisture sensitivity level
Printed on moisture barrier bag
Variation: AAL-1
Table 13–6. 672-Pin FineLine BGA Package Outline Dimensions
Millimeters
Symbol
Min.
Nom.
Max.
A
–
–
3.50
A1
0.30
–
–
A2
0.25
–
3.00
A3
–
–
2.50
D
27.00 BSC
E
27.00 BSC
b
e
13–6
Stratix Device Handbook, Volume 2
0.50
0.60
0.70
1.00 BSC
Altera Corporation
July 2005
Package Information for Stratix Devices
Figure 13–2 shows a package outline for the 672-pin FineLine BGA
packaging.
Figure 13–2. 672-Pin FineLine BGA Package Outline
TOP VIEW
BOTTOM VIEW
D
Pin A1
Corner
Pin A1 ID
e
E
b
e
A
A2
A3
A1
Altera Corporation
July 2005
13–7
Stratix Device Handbook, Volume 2
Package Outlines
780-Pin FineLine BGA - Flip Chip
■
■
■
All dimensions and tolerances conform to ASME Y14.5M - 1994.
Controlling dimension is in millimeters.
Pin A1 may be indicated by an ID dot, or a special feature, in its
proximity on package surface.
Tables 13–7 and 13–8 show the package information and package outline
figure references, respectively, for the 780-pin FineLine BGA packaging.
Table 13–7. 780-Pin FineLine BGA Package Information
Description
Specification
Ordering code reference
F
Package acronym
FineLine BGA
Substrate material
BT
Solder ball composition
Regular: 63Sn:37Pb (Typ.)
Pb-free: Sn:3Ag:0.5Cu (Typ.)
JEDEC outline reference
MS-034
Maximum lead coplanarity
0.008 inches (0.20 mm)
Weight
8.9 g
Moisture sensitivity level
Printed on moisture barrier bag
variation: AAM-1
Table 13–8. 780-Pin FineLine BGA Package Outline Dimensions
Millimeters
Symbol
A
Min.
Nom.
Max.
–
–
3.50
A1
0.30
–
–
A2
0.25
–
3.00
A3
–
–
2.50
D
29.00 BSC
E
b
e
13–8
Stratix Device Handbook, Volume 2
29.00 BSC
0.50
0.60
0.70
1.00 BSC
Altera Corporation
July 2005
Package Information for Stratix Devices
Figure 13–3 shows a package outline for the 780-pin FineLine BGA
packaging.
Figure 13–3. 780-Pin FineLine BGA Package Outline
TOP VIEW
BOTTOM VIEW
D
Pin A1
Corner
Pin A1 ID
e
E
b
e
A
A2
A3
A1
Altera Corporation
July 2005
13–9
Stratix Device Handbook, Volume 2
Package Outlines
956-Pin Ball Grid Array (BGA) - Flip Chip
■
■
■
All dimensions and tolerances conform to ASME Y14.5M - 1994.
Controlling dimension is in millimeters.
Pin A1 may be indicated by an ID dot, or a special feature, in its
proximity on package surface.
Tables 13–9 and 13–10 show the package information and package
outline figure references, respectively, for the 956-pin BGA packaging.
Table 13–9. 956-Pin BGA Package Information
Description
Specification
Ordering code reference
B
Package acronym
BGA
Substrate material
BT
Solder ball composition
Regular: 63Sn:37Pb (Typ.)
Pb-free: Sn:3Ag:0.5Cu (Typ.)
JEDEC outline reference
MS-034
Maximum lead coplanarity
0.008 inches (0.20 mm)
Weight
14.6 g
Moisture sensitivity level
Printed on moisture barrier bag
Variation: BAU-1
Table 13–10. 956-Pin BGA Package Outline Dimensions
Millimeters
Symbol
A
Min.
Nom.
Max.
–
–
3.50
A1
0.30
–
–
A2
0.25
–
3.00
A3
–
–
2.50
D
40.00 BSC
E
b
e
13–10
Stratix Device Handbook, Volume 2
40.00 BSC
0.60
0.75
0.90
1.27 BSC
Altera Corporation
July 2005
Package Information for Stratix Devices
Figure 13–4 shows a package outline for the 956-pin BGA packaging.
Figure 13–4. 956-Pin BGA Package Outline
TOP VIEW
BOTTOM VIEW
D
30 28 26 24 22 20 18 16 14 12 10 8 6 4 2
31 29 27 25 23 21 19 17 15 13 11 9 7 5 3 1
Pin A1
Corner
A
C
Pin A1 ID
E
e
G
J
L
N
E
R
U
W
AA
AC
AE
AG
AJ
AL
b
B
D
F
H
K
M
P
T
V
Y
AB
AD
AF
AH
AK
e
A
A2
A3
A1
Altera Corporation
July 2005
13–11
Stratix Device Handbook, Volume 2
Package Outlines
1,020-Pin FineLine BGA - Flip Chip
■
■
■
All dimensions and tolerances conform to ASME Y14.5M - 1994.
Controlling dimension is in millimeters.
Pin A1 may be indicated by an ID dot, or a special feature, in its
proximity on package surface.
Tables 13–11 and 13–12 show the package information and package
outline figure references, respectively, for the 1,020-pin FineLine BGA
packaging.
Table 13–11. 1,020 FineLine BGA Package Information
Description
Specification
Ordering code reference
F
Package acronym
FineLine BGA
Substrate material
BT
Solder ball composition
Regular: 63Sn:37Pb (Typ.)
Pb-free: Sn:3Ag:0.5Cu (Typ.)
JEDEC outline reference
MS-034
Maximum lead coplanarity
0.008 inches (0.20 mm)
Weight
11.5 g
Moisture sensitivity level
Printed on moisture barrier bag
variation: AAP-1
Table 13–12. 1,020-Pin FineLine BGA Package Outline Dimensions
Millimeters
Symbol
Min.
Nom.
Max.
A
–
–
3.50
A1
0.30
–
–
A2
0.25
–
3.00
A3
–
–
2.50
D
33.00 BSC
E
33.00 BSC
b
e
13–12
Stratix Device Handbook, Volume 2
0.50
0.60
0.70
1.00 BSC
Altera Corporation
July 2005
Package Information for Stratix Devices
Figure 13–5 shows a package outline for the 1,020-pin FineLine BGA
packaging.
Figure 13–5. 1,020-Pin FineLine BGA Package Outline
TOP VIEW
BOTTOM VIEW
Pin A1
Corner
D
Pin A1 ID
e
E
b
e
A
A2
A3
A1
Altera Corporation
July 2005
13–13
Stratix Device Handbook, Volume 2
Package Outlines
1,508-Pin FineLine BGA - Flip Chip
■
■
■
All dimensions and tolerances conform to ASME Y14.5M - 1994.
Controlling dimension is in millimeters.
Pin A1 may be indicated by an ID dot, or a special feature, in its
proximity on package surface.
Tables 13–13 and 13–14 show the package information and package
outline figure references, respectively, for the 1,508-pin FineLine BGA
packaging.
Table 13–13. 1,508-Pin FineLine BGA Package Information
Description
Specification
Ordering code reference
F
Package acronym
FineLine BGA
Substrate material
BT
Solder ball composition
Regular: 63Sn:37Pb (Typ.)
Pb-free: Sn:3Ag:0.5Cu (Typ.)
JEDEC outline reference
MS-034
Maximum lead coplanarity
0.008 inches (0.20 mm)
Weight
14.6 g
Moisture sensitivity level
Printed on moisture barrier bag
Variation: AAU-1
Table 13–14. 1,508-Pin FineLine BGA Package Outline Dimensions
Millimeters
Symbol
Min.
Nom.
Max.
A
–
–
3.50
A1
0.30
–
–
A2
0.25
–
3.00
A3
–
–
2.50
D
40.00 BSC
E
40.00 BSC
b
e
13–14
Stratix Device Handbook, Volume 2
0.50
0.60
0.70
1.00 BSC
Altera Corporation
July 2005
Package Information for Stratix Devices
Figure 13–6 shows a package outline for the 1,508-pin FineLine BGA
packaging.
Figure 13–6. 1,508-Pin FineLine BGA Package Outline
TOP VIEW
BOTTOM VIEW
D
Pin A1
Corner
Pin A1 ID
e
E
b
e
A
A2
A3
A1
Altera Corporation
July 2005
13–15
Stratix Device Handbook, Volume 2
Package Outlines
13–16
Stratix Device Handbook, Volume 2
Altera Corporation
July 2005
14. Designing with
1.5-V Devices
C51012-1.1
Introduction
The CycloneTM FPGA family provides the best solution for high-volume,
cost-sensitive applications. Stratix® and Cyclone devices are fabricated on
a leading-edge 1.5-V, 0.13-µm, all-layer copper SRAM process.
Using a 1.5-V operating voltage provides the following advantages:
■
■
■
Lower power consumption compared to 2.5-V or 3.3-V devices.
Lower operating temperature.
Less need for fans and other temperature-control elements.
Since many existing designs are based on 5.0-V, 3.3-V and 2.5-V power
supplies, a voltage regulator may be required to lower the voltage supply
level to 1.5-V. This document provides guidelines for designing with
Stratix and Cyclone devices in mixed-voltage and single-voltage systems
and provides examples using voltage regulators. This document also
includes information on:
■
■
■
■
■
Power
Sequencing &
Hot Socketing
Power Sequencing & Hot Socketing
Using MultiVolt I/O Pins
Voltage Regulators
1.5-V Regulator Application Examples
Board Layout
Because 1.5-V Cyclone FPGAs can be used in a mixed-voltage
environment, they have been designed specifically to tolerate any
possible power-up sequence. Therefore, the VCCIO and VCCINT power
supplies may be powered in any order.
You can drive signals into Cyclone FPGAs before and during power up
without damaging the device. In addition, Cyclone FPGAs do not drive
out during power up since they are tri-stated during power up. Once the
device reaches operating conditions and is configured, Cyclone FPGAs
operate as specified by the user.
f
Altera Corporation
January 2005
See the Stratix FPGA Family Data Sheet and the Cyclone FPGA Family Data
Sheet for more information.
14–1
Using MultiVolt I/O Pins
Using MultiVolt
I/O Pins
Cyclone FPGAs require a 1.5-V VCCINT and a 3.3-V, 2.5-V, 1.8-V, or 1.5-V
I/O supply voltage level (VCCIO). All pins, including dedicated inputs,
clock, I/O, and JTAG pins, are 3.3-V tolerant before and after VCCINT and
VCCIO are powered.
When VCCIO is connected to 1.5-V, the output is compatible with 1.5-V
logic levels. The output pins can be made 1.8-V, 2.5-V, or 3.3-V compatible
by using open-drain outputs pulled up with external resistors. You can
use external resistors to pull open-drain outputs up with a 1.8-V, 2.5-V, or
3.3-V VCCIO. Table 14–1 summarizes Cyclone MultiVolt I/O support.
Table 14–1. Cyclone MultiVolt I/O Support Note (1)
Input Signal
VCCIO (V)
1.5-V
1.8-V
Output Signal
1.5-V
1.8-V
2.5-V
3.3-V
v
v
v (2)
v (2)
v
v
v (3)
v
v
v (5)
v (5)
v
v (7)
v (7)
v (7)
v
v
2.5-V
v
3.3-V
v (4)
v
5.0-V
v (6)
1.5-V
1.8-V
2.5-V
3.3-V
5.0-V
v
v (8)
Notes to Table 14–1:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
The PCI clamping diode must be disabled to drive an input with voltages higher than VCCIO.
When VCCIO = 1.5-V and a 2.5-V or 3.3-V input signal feeds an input pin, higher pin leakage current is expected.
When VCCIO = 1.8-V, a Cyclone device can drive a 1.5-V device with 1.8-V tolerant inputs.
When VCCIO = 3.3-V and a 2.5-V input signal feeds an input pin, the VCCIO supply current will be slightly larger
than expected.
When VCCIO = 2.5-V, a Cyclone device can drive a 1.5-V or 1.8-V device with 2.5-V tolerant inputs.
Cyclone devices can be 5.0-V tolerant with the use of an external resistor and the internal PCI clamp diode.
When VCCIO = 3.3-V, a Cyclone device can drive a 1.5-V, 1.8-V, or 2.5-V device with 3.3-V tolerant inputs.
When VCCIO = 3.3-V, a Cyclone device can drive a device with 5.0-V LVTTL inputs but not 5.0-V LVCMOS inputs.
14–2
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
Figure 14–1 shows how Cyclone FPGAs interface with 3.3--V and 2.5-V
devices while operating with a 1.5-V VCCINT to increase performance and
save power.
Figure 14–1. Cyclone FPGAs Interface with 3.3-V & 2.5-V Devices
3.3 V
2.5 V
1.5 V
Cyclone Device
3.3-V TTL
3.3-V Device
3.3-V CMOS
Voltage
Regulators
VCCINT = 1.5 V
VCCIO1 = 2.5 V
VCCIO2 = 3.3 V
2.5-V TTL
2.5-V Device
2.5-V CMOS
This section explains how to generate a 1.5-V supply from another system
supply. Supplying power to the 1.5-V logic array and/or I/O pins
requires a 5.0-V- or 3.3-V-to-1.5-V voltage regulator. A linear regulator is
ideal for low-power applications because it minimizes device count and
has acceptable efficiency for most applications. A switching voltage
regulator provides optimal efficiency. Switching regulators are ideal for
high-power applications because of their high efficiency.
This section will help you decide which regulator to use in your system,
and how to implement the regulator in your design. There are several
companies that provide voltage regulators for low-voltage devices, such
as Linear Technology Corporation, Maxim Integrated Products, Intersil
Corporation (Elantec), and National Semiconductor Corporation.
Altera Corporation
January 2005
14–3
Stratix Device Handbook, Volume 2
Voltage Regulators
Table 14–2 shows the terminology and specifications commonly
encountered with voltage regulators. Symbols are shown in parentheses.
If the symbols are different for linear and switching regulators, the linear
regulator symbol is listed first.
Table 14–2. Voltage Regulator Specifications & Terminology (Part 1 of 2)
Specification/Terminology
Description
Input voltage range (VIN,VCC)
Minimum and maximum input voltages define the input voltage range, which
is determined by the regulator process voltage capabilities.
Line regulation
(line regulation, VOUT)
Line regulation is the variation of the output voltage (VOUT) with changes in
the input voltage (VIN). Error amplifier gain, pass transistor gain, and output
impedance all influence line regulation. Higher gain results in better
regulation. Board layout and regulator pin-outs are also important because
stray resistance can introduce errors.
Load regulation
(load regulation, VOUT)
Load regulation is a variation in the output voltage caused by changes in the
input supply current. Linear Technology regulators are designed to minimize
load regulation, which is affected by error amplifier gain, pass transistor gain,
and output impedance.
Output voltage selection
Output voltage selection is adjustable by resistor voltage divider networks,
connected to the error amplifier input, that control the output voltage. There
are multiple output regulators that create 5.0-, 3.3-, 2.5-, 1.8- and 1.5-V
supplies.
Quiescent current
Quiescent current is the supply current during no-load or quiescent state.
This current is sometimes used as a general term for a supply current used
by the regulator.
Dropout voltage
Dropout voltage is the difference between the input and output voltages
when the input is low enough to cause the output to drop out of regulation.
The dropout voltage should be as low as possible for better efficiency.
Current limiting
Voltage regulators are designed to limit the amount of output current in the
event of a failing load. A short in the load causes the output current and
voltage to decrease. This event cuts power dissipation in the regulator during
a short circuit.
Thermal overload protection
This feature limits power dissipation if the regulator overheats. When a
specified temperature is reached, the regulator turns off the output drive
transistors, allowing the regulator to cool. Normal operation resumes once
the regulator reaches a normal operating temperature.
Reverse current protection
If the input power supply fails, large output capacitors can cause a substantial
reverse current to flow backward through the regulator, potentially causing
damage. To prevent damage, protection diodes in the regulator create a path
for the current to flow from VOUT to VIN.
Stability
The dominant pole placed by the output capacitor influences stability.
Voltage regulator vendors can assist you in output capacitor selection for
regulator designs that differ from what is offered.
14–4
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
Table 14–2. Voltage Regulator Specifications & Terminology (Part 2 of 2)
Specification/Terminology
Description
Minimum load requirements
A minimum load from the voltage divider network is required for good
regulation, which also serves as the ground for the regulator’s current path.
Efficiency
Efficiency is the division of the output power by the input power. Each
regulator model has a specific efficiency value. The higher the efficiency
value, the better the regulator.
Linear Voltage Regulators
Linear voltage regulators generate a regulated output from a larger input
voltage using current pass elements in a linear mode. There are two types
of linear regulators available: one using a series pass element and another
using a shunt element (e.g., a zener diode). Altera recommends using
series linear regulators because shunt regulators are less efficient.
Series linear regulators use a series pass element (i.e., a bipolar transistor
or MOSFET) controlled by a feedback error amplifier (see Figure 14–2) to
regulate the output voltage by comparing the output to a reference
voltage. The error amplifier drives the transistor further on or off
continuously to control the flow of current needed to sustain a steady
voltage level across the load.
Figure 14–2. Series Linear Regulator
VOUT
VIN
Error
Amplifier
+
–
Reference
Altera Corporation
January 2005
14–5
Stratix Device Handbook, Volume 2
Voltage Regulators
Table 14–3 shows the advantages and disadvantages of linear regulators
compared to switching regulators.
Table 14–3. Linear Regulator Advantages & Disadvantages
Advantages
Disadvantages
Requires few supporting components
Low cost
Requires less board space
Quick transient response
Better noise and drift characteristics
No electromagnetic interference (EMI)
radiation from the switching
components
Tighter regulation
Less efficient (typically 60%)
Higher power dissipation
Larger heat sink requirements
You can minimize the difference between the input and output voltages
to improve the efficiency of linear regulators. The dropout voltage is the
minimum allowable difference between the regulator’s input and output
voltage.
Linear regulators are available with fixed, variable, single, or multiple
outputs. Multiple-output regulators can generate multiple outputs (e.g.,
1.5- and 3.3-V outputs). If the board only has a 5.0-V power voltage
supply, you should use multiple-output regulators. The logic array
requires a 1.5-V power supply, and a 3.3-V power supply is required to
interface with 3.3- and 5.0-V devices. However, fixed-output regulators
have fewer supporting components, reducing board space and cost.
Figure 14–3 shows an example of a three-terminal, fixed-output linear
regulator.
Figure 14–3. Three-Terminal, Fixed-Output Linear Regulator
Linear Regulator
VIN
IN
OUT
1.5 V
ADJ
Adjustable-output regulators contain a voltage divider network that
controls the regulator’s output. Figure 14–4 shows how you can also use
a three-terminal linear regulator in an adjustable-output configuration.
14–6
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
Figure 14–4. Adjustable-Output Linear Regulator
Linear Regulator
VIN
IN
+
OUT
ADJ
C1
VOUT = [VREF × (1 +
+
VREF
R1
R1
R2
)] + (IADJ × R1)
C2
IADJ
R2
Switching Voltage Regulators
Step-down switching regulators can provide 3.3-V-to-1.5-V conversion
with up to 95% efficiencies. This high efficiency comes from minimizing
quiescent current, using a low-resistance power MOSFET switch, and, in
higher-current applications, using a synchronous switch to reduce diode
losses.
Switching regulators supply power by pulsing the output voltage and
current to the load. Table 14–4 shows the advantages and disadvantages
of switching regulators compared to linear regulators. For more
information on switching regulators, see Application Note 35: Step Down
Switching Regulators from Linear Technology.
Table 14–4. Switching Regulator Advantages & Disadvantages
Advantages
Highly efficient (typically >80%)
Reduced power dissipation
Smaller heat sink requirements
Wider input voltage range
High power density
Disadvantages
Generates EMI
Complex to design
Requires 15 or more supporting
components
Higher cost
Requires more board space
There are two types of switching regulators, asynchronous and
synchronous. Asynchronous switching regulators have one field effect
transistor (FET) and a diode to provide the current path while the FET is
off (see Figure 14–5).
Altera Corporation
January 2005
14–7
Stratix Device Handbook, Volume 2
Voltage Regulators
Figure 14–5. Asynchronous Switching Regulator
MOSFET
Switch Node
VIN
VOUT
High-Frequency
Circulating Path
LOAD
Synchronous switching regulators have a voltage- or current-controlled
oscillator that controls the on and off time of the two MOSFET devices
that supply the current to the circuit (see Figure 14–6).
Figure 14–6. Voltage-Controlled Synchronous Switching Regulator
VIN
Voltage-Controlled
Oscillator (VCO)
VOUT
Maximum Output Current
Select an external MOSFET switching transistor (optional) based on the
maximum output current that it can supply. Use a MOSFET with a low
on-resistance and a voltage rating high enough to avoid avalanche
breakdown. For gate-drive voltages less than 9-V, use a logic-level
MOSFET. A logic-level MOSFET is only required for topologies with a
controller IC and an external MOSFET.
14–8
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
Selecting Voltage Regulators
Your design requirements determine which voltage regulator you need.
The key to selecting a voltage regulator is understanding the regulator
parameters and how they relate to the design.
The following checklist can help you select the proper regulator for your
design:
■
■
■
■
■
■
Do you require a 3.3-V, 2.5-V, and 1.5-V output (VOUT)?
What precision is required on the regulated 1.5-V supplies (line and
load regulation)?
What supply voltages (VIN or VCC) are available on the board?
What voltage variance (input voltage range) is expected on VIN or
VCC?
What is the maximum ICC (IOUT) required by your Altera® device?
What is the maximum current surge (IOUT(MAX)) that the regulator
will need to supply instantaneously?
Choose a Regulator Type
If required, select either a linear, asynchronous switching, or
synchronous switching regulator based on your output current, regulator
efficiency, cost, and board-space requirements. DC-to-DC converters
have output current capabilities from 1 to 8 A. You can use a controller
with an external MOSFET rated for higher current for higher-outputcurrent applications.
Calculate the Maximum Input Current
Use the following equation to estimate the maximum input current based
on the output power requirements at the maximum input voltage:
IIN,DC(MAX) =
VOUT × IOUT(MAX)
η × VIN(MAX)
Where η is nominal efficiency: typically 90% for switching regulators,
60% for linear 2.5-V-to-1.5-V conversion, 45% for linear 3.3-V-to-1.5-V
conversion, and 30% for linear 5.0-V-to-1.5-V conversion.
Once you identify the design requirements, select the voltage regulator
that is best for your design. Tables 14–5 and 14–6 list a few Linear
Technology and Elantec regulators available at the time this document
Altera Corporation
January 2005
14–9
Stratix Device Handbook, Volume 2
Voltage Regulators
was published. There may be more regulators to choose from depending
on your design specification. Contact a regulator manufacturer for
availability.
Table 14–5. Linear Technology 1.5-V Output Voltage Regulators
Voltage Regulator
Regulator Type
Total Number of
Components
VIN (V)
IOUT (A)
Special Features
LT1573
Linear
10
2.5 or 3.3 (1)
6
–
LT1083
Linear
5
5.0
7.5
–
LT1084
Linear
5
5.0
5
–
LT1085
Linear
5
5.0
3
Inexpensive solution
LTC1649
Switching
22
3.3
15
Selectable output
LTC1775
Switching
17
5.0
5
–
Note to Table 14–5:
(1)
A 3.3-V VIN requires a 3.3-V supply to the regulator’s input and 2.5-V supply to bias the transistors.
Table 14–6. Elantec 1.5-V Output Voltage Regulators
Voltage Regulator
Regulator Type
Total Number of
Components
VIN (V)
IOUT (A)
Special Features
EL7551C
Switching
11
5.0
1
–
EL7564CM
Switching
13
5.0
4
–
EL7556BC
Switching
21
5.0
6
–
EL7562CM
Switching
17
3.3 or 5.5
2
–
EL7563CM
Switching
19
3.3
4
–
Voltage Divider Network
Design a voltage divider network if you are using an adjustable output
regulator. Follow the controller or converter IC’s instructions to adjust
the output voltage.
1.5-V Regulator Circuits
This section contains the circuit diagrams for the voltage regulators
discussed in this chapter. You can use the voltage regulators in this
section to generate a 1.5-V power supply. See the voltage regulator data
sheet to find detailed specifications. If you require further information
that is not shown in the data sheet, contact the regulator’s vendor.
14–10
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
Figures 14–7 through 14–12 show the circuit diagrams of Linear
Technology voltage regulators listed in Table 14–5.
The LT1573 linear voltage regulator converts 2.5-V to 1.5-V with an
output current of 6A (see Figure 14–7).
Figure 14–7. LT1573: 2.5-V-to-1.5-V/6.0-A Linear Voltage Regulator
LT1573
FB
LATCH
CTIME
0.5 μF
(3)
+
SHDN (2)
GND
CIN1
COMP
+
VIN1
2.5 V
(1)
VOUT
VIN
RD
6Ω
1/2 W
DRIVE
RB
200 Ω
1/8 W
Motorola
D45H11
VIN2
3.3 V
+
+
CIN2
COUT
(4)
(1)
R1
186 Ω
1/8 W
VOUT
1.5 V
LOAD
R2 1k
1/8 W
Notes to Figure 14–7:
(1)
(2)
(3)
(4)
CIN1 and COUT are AVX 100-μF/10-V surface-mount tantalum capacitors.
Use SHDN (active high) to shut down the regulator.
CTIME is a 0.5-μF capacitor for 100-ms time out at room temperature.
CIN2 is an AVX 15-μF/10-V surface-mount tantalum capacitor.
Use adjustable 5.0- to 1.5-V regulators (shown in Figures 14–8 through
14–10) for 3.0- to 7.5-A low-cost, low-device-count, board-space-efficient
solutions.
Altera Corporation
January 2005
14–11
Stratix Device Handbook, Volume 2
Voltage Regulators
Figure 14–8. LT1083: 5.0-V-to-1.5-V/7.5-A Linear Voltage Regulator
VIN
IN
LT1083
ADJ
+
(1) C1
VOUT = 1.25 V × (1 +
OUT
R2
R1
)
R1
5 kΩ
10 μF
R2
1 kΩ
C2
+
10 μF
Note to Figure 14–8:
(1)
This capacitor is necessary to maintain the voltage level at the input regulator.
There could be a voltage drop at the input if the voltage supply is too far away.
Figure 14–9. LT1084: 5.0-V-to-1.5-V/5.0-A Linear Voltage Regulator
VIN
IN
LT1083
ADJ
+
(1) C1
10 μF
R2
1 kΩ
VOUT = 1.25 V × (1 +
OUT
R2
R1
)
R1
5 kΩ
C2
+
10 μF
Note to Figure 14–9:
(1)
This capacitor is necessary to maintain the voltage level at the input regulator.
There could be a voltage drop at the input if the voltage supply is too far away.
14–12
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
Figure 14–10. LT1085: 5.0-V-to-1.5-V/3-A Linear Voltage Regulator
VIN
IN
LT1084
ADJ
+
(1) C1
VOUT = 1.25 V × (1 +
OUT
R2
R1
)
R1
5 kΩ
10 μF
R2
1 kΩ
C2
+
10 μF
Note to Figure 14–10:
(1)
This capacitor is necessary to maintain the voltage level at the input regulator.
There could be a voltage drop at the input if the voltage supply is too far away.
Figure 14–11 shows a high-efficiency switching regulator circuit diagram.
A selectable resistor network controls the output voltage. The resistor
values in Figure 14–11 are selected for 1.5-V output operation.
Figure 14–11. LT1649: 3.3-V-to-1.5-V/15-A Asynchronous Switching Regulator
VIN
3.3 V
MBR0530 (1)
+
RIMAX
50 kΩ
22 kΩ
1 μF
P VCC1
G1
P VCC2
I FB
V CC
G2
I MAX
SHUTDOWN
10 μF
+
CIN
3,300 μF
LEXT (3) 1.2 μH
VOUT
1 kΩ
LTC1649
Q3
IRF7801
1.5 V
(15 A)
R1
2.16 kΩ
FB
SHDN
V IN
COMP
C+
SS
C–
GND
RC
7.5 kΩ
Q1, Q2
IRF7801
Two in
Parallel (2)
+
1 μF
COUT
4,400 μF
R2
12.7 kΩ
CP OUT
+
0.1 μF
C1
220 pF
MBR0530
10 μF
0.33 μF
CC
0.01 μF
Notes to Figure 14–11:
(1)
(2)
(3)
MBR0530 is a Motorola device.
IRF7801 is a International Rectifier device.
See the Panasonic 12TS-1R2HL device.
Altera Corporation
January 2005
14–13
Stratix Device Handbook, Volume 2
Voltage Regulators
Figure 14–12 shows synchronous switching regulator with adjustable
outputs.
Figure 14–12. LTC1775: 5.0-V-to-1.5-V/5-A Synchronous Switching Regulator
RF
1Ω
1
2
CSS
0.1 μF
CC1
2.2 nF
RC
10 kΩ
3
INTVCC
4
5
CC2
220 pF
6
7
OPEN
8
EXTVCC
VIN
SYNC
TK
RUN/SS
SW
FCB
TG
ITH
SGND
VOSENSE
VPROG
BOOST
INTVCC
BG
PGND
16
15
13
11
CB
0.22 μF
DB
CMDSH-3
10
9
CIN (1)
15 μF
35 V
×3
CF
0.1 μF
14
12
VIN
5V
CVCC
4.7 μF
M1
1/2 FDS8936A
L1 (2)
6.1 μH
D1
MBRS140
M2
1/2 FDS8936A
VOUT
1.5 V
5A
R2
2.6 kΩ
R1
10 kΩ
COUT (3)
680 μF
4V
×2
Notes to Figure 14–12:
(1)
(2)
(3)
This is a KEMETT495X156M035AS capacitor.
This is a Sumida CDRH127-6R1 inductor.
This is a KEMETT510X687K004AS capacitor.
14–14
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
Figures 14–13 through 14–17 show the circuit diagrams of Elantec voltage
regulators listed in Table 14–6.
Figures 14–13 through 14–15 show the switching regulator that converts
5.0-V to 1.5-V with different output current.
Figure 14–13. EL7551C: 5.0-V-to-1.5-V/1-A Synchronous Switching Regulator
1
C3
0.1 μF
R3
39 kΩ
C4
270 pF
SGND
PGND
COSC
VREF
3
5
6
FB
PGND
VDRV
LX
PGND
LX
VIN
7
VIN
5.0 V
R2
539 Ω
14
VDD
C1
10 μF
Ceramic
C5
0.1 μF
15
2
4
16
13
12
11
10
VIN
VHI
EN
PGND
8
R1
1 kΩ
L1
10 μH
V0
1.5 V
1A
C6
0.1 μF
C7
47 μF
9
EL7551C
Altera Corporation
January 2005
14–15
Stratix Device Handbook, Volume 2
Voltage Regulators
Figure 14–14. EL7564CM: 5.0-V-to-1.5-V/4-A Synchronous Switching Regulator
1
C5
0.1 μF
20
VREF
EN
SGND
FB
COSC
PG
2
3
19
18
C4
390 pF
R4
22 Ω
4
C3
0.22 μF
5
VDD
VDRV
VTJ
VHI
C2
2.2 nF
17
16
D1
C6
0.22 μF
6
15
LX
PGND
7
14
PGND
C1
330 μF
8
VIN
5.0 V
9
10
L1
4.7 μH
LX
VIN
PGND
STP
PGND
PGND
STN
C7
330 μF
R2
539 Ω
C10
100 pF
V0
1.5 V
4A
13
12
R1
1 kΩ
11
EL7564CM
14–16
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
Figure 14–15. EL7556BC: 5.0-V-to-1.5-V/6-A Synchronous Switching Regulator
R3
50 Ω
R4
100 Ω
VIN
1
C4 (1)
0.1 μF
2
C7 (1)
39 pF
3
C8 (1)
220 pF
R5
5.1 Ω
4
5
6
7
8
VIN
C12
1.0 μF
C9 (5)
660 μF
9
10
11
12
13
14
FB1
FB2
CREF
CP
CSLOPE
C2V
COSC
VSS
VDD
VHI
VIN
LX
VSSP
LX
LX
VIN
VSSP
LX
VSSP
VSSP
VSSP
VSSP
VSSP
VCC2DET
OUTEN
28
27
C5 (2)
1 μF
R1
20 Ω
26
25
22
21
D4
Optional (3), (4)
D2 (3)
D1 (3)
C11 (2)
0.22 μF
R6
39.2 Ω
24
23
D3 (3)
C6 (1)
0.1 μF
L1
2.5 μH
VOUT
R3
= 1.5 V × (1 +
)
R4
20
19
18
TEST 17
16
PWRGD
15
OT
C10 (6)
1.0 mF
EL7556BC
Notes to Figures 14–13 to 14–15:
(1)
(2)
(3)
(4)
(5)
(6)
These capacitors are ceramic capacitors.
These capacitors are ceramic or tantalum capacitor.
These are BAT54S fast diodes.
D4 is only required for EL7556ACM.
This is a Sprague 293D337X96R3 2X330μF capacitor.
This is a Sprague 293D337X96R3 3X330μF capacitor.
Altera Corporation
January 2005
14–17
Stratix Device Handbook, Volume 2
Voltage Regulators
Figures 14–16 and 14–17 show the switching regulator that converts 3.3 V
to 1.5 V with different output currents.
Figure 14–16. EL7562CM: 3.3-V to 1.5-V/2-A Synchronous Switching Regulator
1
C3
R3
0.1 μF
39 Ω
C4
270 pF
2
3
SGND
PGND
COSC
VREF
VDD
FB
16
15
C5
0.1 μF
14
D2
4
5
C1
100 μF
C2
0.1 μF
6
7
VIN
3.3 V
8
PGND
VDRV
PGND
LX
VIN
LX
VIN
VHI
EN
PGND
13
D3
D4
C8
0.1 μF
12
11
C9
0.1 μF
C6
0.1 μF
10
L1
2.5 μH
9
C7
100 μF
EL7562CM
R2
539 Ω
VOUT
1.5 V
2A
R1
1 kΩ
Figure 14–17. EL7563CM: 3.3-V to 1.5-V/4-A Synchronous Switching Regulator
C5
0.1 μF
1
2
VREF
EN
SGND
FB
COSC
PG
20
19
C4
390 pF
3
R4
22 Ω
4
C3
0.22 μF
C2
2.2 nF
5
VDD
VDRV
VTJ
VHI
18
D2
17
D3
16
C6
0.22 μF
6
C1
330 μF
VIN
3.3 V
7
8
9
10
PGND
LX
PGND
LX
VIN
PGND
STP
PGND
STN
PGND
D4
D1
C8
0.22 μF
C9
0.1 μF
15
14
L1
2.5 μH
13
12
C7
330 μF
C10
2.2 nF
R2
513 Ω
VOUT
1.5 V
4A
11
R1
1 kΩ
EL7563CM
14–18
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
1.5-V Regulator
Application
Examples
The following sections show the process used to select a voltage regulator
for three sample designs. The regulator selection is based on the amount
of power that the Cyclone device consumes. There are 14 variables to
consider when selecting a voltage regulator. The following variables
apply to Cyclone device power consumption:
■
■
■
■
■
■
■
■
■
fMAX
Output and bidirectional pins
Average toggle rate for I/O pins (togIO)
Average toggle rate for logic elements (LEs) (togLC)
User-mode ICC consumption
Maximum power-up ICCINT requirement
Utilization
VCCIO supply level
VCCINT supply level
The following variables apply to the voltage regulator:
■
■
■
■
■
Output voltage precision requirement
Supply voltage on the board
Voltage supply output current
Variance of board supply
Efficiency
Different designs have different power consumptions based on the
variables listed. Once you calculate the Cyclone device’s power
consumption, you must consider how much current the Cyclone device
needs. You can use the Cyclone power calculator (available at
www.altera.com) or the PowerGaugeTM tool in the Quartus II software to
determine the current needs. Also check the maximum power-up current
requirement listed in the Power Consumption section of the Cyclone
FPGA Family Data Sheet because the power-up current requirement may
exceed the user-mode current consumption for a specific design.
Once you determine the minimum current the Cyclone device requires,
you must select a voltage regulator that can generate the desired output
current with the voltage and current supply that is available on the board
using the variables listed in this section. An example is shown to illustrate
the voltage regulator selection process.
Altera Corporation
January 2005
14–19
Stratix Device Handbook, Volume 2
1.5-V Regulator Application Examples
Synchronous Switching Regulator Example
This example shows a worst-case scenario for power consumption where
the design uses all the LEs and RAM. Table 14–7 shows the design
requirements for 1.5-V design using a Cyclone EP1C12 FPGA.
Table 14–7. Design Requirements for the Example EP1C12F324C
Design Requirement
Value
Output voltage precision requirement
±5%
Supply voltages available on the board
3.3 V
Voltage supply output current available for this
section (II N , D C ( M A X ) )
2A
Variance of board supply (VIN)
±5%
fMAX
150 MHz
Average togIO
12.5%
Average togLC
12.5%
Utilization
100%
Output and bidirectional pins
125
VCCIO supply level
3.3 V
VCCINT supply level
1.5 V
Efficiency
≥90%
Table 14–8 uses the checklist on page 14–9 to help select the appropriate
voltage regulator.
Table 14–8. Voltage Regulator Selection Process for EP1C12F324C Design (Part 1 of 2)
Output voltage requirements
Supply voltages
Supply variance from Linear Technology data sheet
Estimated IC C I N T
Use Cyclone Power Calculator
Estimated IC C I O if regulator powers VC C I O
Use Cyclone Power Calculator (not applicable in this example
because VC C I O = 3.3 V)
Total user-mode current consumption
IC C = I C C I N T + I C C I O
14–20
Stratix Device Handbook, Volume 2
VOUT = 1.5 V
VIN OR VCC = 3.3 V
Supply variance = ±5%
ICCINT = 620 mA
ICCIO = N/A
IC C = 620 mA
Altera Corporation
January 2005
Designing with 1.5-V Devices
Table 14–8. Voltage Regulator Selection Process for EP1C12F324C Design (Part 2 of 2)
EP1C12 maximum power-up current requirement
See Power Consumption section of the Cyclone FPGA Family
Data Sheet for other densities
IP U C ( M A X ) = 900 mA
Maximum output current required
Compare IC C with IP U C ( M A X )
IO U T ( M A X ) = 900 mA
Voltage regulator selection
See Linear Technology LTC 1649 data sheet
See Intersil (Elantec) EL7562C data sheet
LTC1649 IO U T ( M A X ) = 15 A
EL7562C IO U T ( M A X ) = 2 A
LTC1649
Nominal efficiency (η)
Nominal efficiency (η) = > 90%
Line and load regulation
Line regulation + load regulation = (0.17 mV + 7 mV)/ 1.5 V × 100%
Minimum input voltage (VIN(MIN))
(VIN(MIN)) = VIN(1 – ΔVIN) = 3.3V(1 – 0.05)
Maximum input current
IIN, DC(MAX) = (VOUT × IOUT(MAX))/(η× VIN(MIN))
Line and Load
Regulation = 0.478% < 5%
(VIN(MIN)) = 3.135 V
IIN, DC(MAX) = 478 mA < 2 A
EL7562C
Nominal efficiency (η)
Nominal efficiency (η) = > 95%
Line and load regulation
Line regulation + load regulation = (0.17 mV + 7 mV)/ 1.5 V × 100%
Minimum input voltage (VIN(MIN))
(VIN(MIN)) = VIN(1 – ΔVIN) = 3.3V(1 – 0.05)
Maximum input current
IIN, DC(MAX) = (VOUT × IOUT(MAX))/(η× VIN(MIN))
Board Layout
Line and Load
Regulation = 0.5% < 5%
(VIN(MIN)) = 3.135 V
IIN, DC(MAX) = 453 mA < 2 A
Laying out a printed circuit board (PCB) properly is extremely important
in high-frequency (≥100 kHz) switching regulator designs. A poor PCB
layout results in increased EMI and ground bounce, which affects the
reliability of the voltage regulator by obscuring important voltage and
current feedback signals. Altera recommends using Gerber files ⎯predesigned layout files⎯supplied by the regulator vendor for your board
layout.
If you cannot use the supplied layout files, contact the voltage regulator
vendor for help on re-designing the board to fit your design requirements
while maintaining the proper functionality.
Altera recommends that you use separate layers for signals, the ground
plane, and voltage supply planes. You can support separate layers by
using multi-layer PCBs, assuming you are using two signal layers.
Altera Corporation
January 2005
14–21
Stratix Device Handbook, Volume 2
Board Layout
Figure 14–18 shows how to use regulators to generate 1.5-V and 2.5-V
power supplies if the system needs two power supply systems. One
regulator is used for each power supply.
Figure 14–18. Two Regulator Solution for Systems that Require 5.0-V, 2.5-V & 1.5-V Supply Levels
PCB
Regulator
5.0 V
1.5 V
1.5-V
Device
Altera
Cyclone
FPGA
Regulator
2.5 V
2.5-V
Device
Figure 14–19 shows how to use a single regulator to generate two
different power supplies (1.5-V and 2.5-V). The use of a single regulator
to generate 1.5-V and 2.5-V supplies from the 5.0-V power supply can
minimize the board size and thus save cost.
Figure 14–19. Single Regulator Solution for Systems that Require 5.0-V, 2.5-V & 1.5-V Supply Levels
PCB
1.5-V
Device
1.5 V
5.0 V
Regulator
Altera
Cyclone
FPGA
2.5 V
2.5-V
Device
14–22
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
Designing with 1.5-V Devices
Split-Plane Method
The split-plane design method reduces the number of planes required by
placing two power supply planes in one plane (see Figure 14–20). For
example, the layout for this method can be structured as follows:
■
■
One 2.5-V plane, covering the entire board
One plane split between 5.0-V and 1.5-V
This technique assumes that the majority of devices are 2.5-V. To support
MultiVolt I/O, Altera devices must have access to 1.5-V and 2.5-V planes.
Figure 14–20. Split Board Layout for 2.5-V Systems With 5.0-V & 1.5-V Devices
5.0 V
PCB
2.5-V
Device
1.5 V
5.0-V
Device
5.0-V
Device
2.5-V
Device
Conclusion
Altera Corporation
January 2005
1.5-V
Device
Altera
Cyclone
FPGA
(1.5 V)
Regulator
2.5-V
Device
1.5-V
Device
2.5-V
Device
With the proliferation of multiple voltage levels in systems, it is
important to design a voltage system that can support a low-power
device like Cyclone devices. Designers must consider key elements of the
PCB, such as power supplies, regulators, power consumption, and board
layout when successfully designing a system that incorporates the lowvoltage Cyclone family of devices.
14–23
Stratix Device Handbook, Volume 2
References
References
Linear Technology Corporation. Application Note 35 (Step Down Switching
Regulators). Milpitas: Linear Technology Corporation, 1989.
Linear Technology Corporation. LT1573 Data Sheet (Low Dropout
Regulator Driver). Milpitas: Linear Technology Corporation, 1997.
Linear Technology Corporation. LT1083/LT1084/LT1085 Data Sheet (7.5 A,
5 A, 3 A Low Dropout Positive Adjustable Regulators). Milpitas: Linear
Technology Corporation, 1994.
Linear Technology Corporation. LTC1649 Data Sheet (3.3V Input High
Power Step-Down Switching Regulator Controller). Milpitas: Linear
Technology Corporation, 1998.
Linear Technology Corporation. LTC1775 Data Sheet (High Power No
Rsense Current Mode Synchronous Step-Down Switching Regulator).
Milpitas: Linear Technology Corporation, 1999.
Intersil Corporation. EL7551C Data Sheet (Monolithic 1 Amp DC:DC StepDown Regulator). Milpitas: Intersil Corporation, 2002.
Intersil Corporation. EL7564C Data Sheet (Monolithic 4 Amp DC:DC StepDown Regulator). Milpitas: Intersil Corporation, 2002.
Intersil Corporation. EL7556BC Data Sheet (Integrated Adjustable 6 Amp
Synchronous Switcher). Milpitas: Intersil Corporation, 2001.
Intersil Corporation. EL7562C Data Sheet (Monolithic 2 Amp DC:DC StepDown Regulator). Milpitas: Intersil Corporation, 2002.
Intersil Corporation. EL7563C Data Sheet (Monolithic 4 Amp DC:DC StepDown Regulator). Milpitas: Intersil Corporation, 2002.
14–24
Stratix Device Handbook, Volume 2
Altera Corporation
January 2005
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