Arria V 器件设计指南

Arria V 器件设计指南
Arria V and Cyclone V Design Guidelines
AN-662-1.0
Application Note
This application note provides a set of checklists that consist of design guidelines,
recommendations, and factors to consider when you create designs using the
Arria® V or Cyclone® V FPGAs.
■
Use this document to help you plan the FPGA and system early in the design
process, which is crucial for a successful design.
■
Follow Altera’s recommendations throughout the design process to achieve good
results, avoid common issues, and improve your design productivity.
Figure 1 shows the Arria V and Cyclone V design flow. The sections in this document
provide the checklists and guidelines for each part of the design flow.
Figure 1. Arria V and Cyclone V Design Flow
Board Design
Power Pins Planning
Early Planning
Specifications
Design Specifications
• IP Selection
Early Board Design
Planning
Device Selection
Early Pin Planning
and I/O Assignment
Design Entry
Configuration Pins
Planning
Design Implementation
Synthesis
and Compilation
I/O and Clock Planning
I/O Features and
Pin Connections
Hierarchical Team-based
Design Planning
Timing Optimization
and Analysis
Functional Timing
Simulation
Clock Planning
Formal Verification
I/O SSN Considerations
Power Analysis
and Optimization
1
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www.altera.com
January 2013
For the Arria V and Cyclone V SoC FPGA device variants, the guidelines in this
document are applicable only to the FPGA portion of the devices.
© 2013 Altera Corporation. All rights reserved. ALTERA, ARRIA, CYCLONE, HARDCOPY, MAX, MEGACORE, NIOS,
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Page 2
Before You Begin
Before You Begin
Before you begin planning and designing your FPGA system, familiarize yourself
with the FPGA device features, and the design tools and IP that are available for the
Arria V or Cyclone V device family.
Table 1. Prerequisites Checklist (Part 1 of 2)
No. v Checklist items
1.

Read through the Device Overview of the FPGA
The Device Overview provides an overview of the capabilities and options available for a
device family. Read through the document to familiarize yourself with the device family
offerings and general features.
For an overview of each FPGA device family, refer to the following documents:
2.

■
Arria V Device Overview
■
Cyclone V Device Overview
Estimate design requirements
Create a rough estimate of the design in the following terms:
3.

■
Basic functions of the product
■
Similar previous designs
■
General device requirements
Review available design tools
Consider the available design, estimators, system builders, and verification tools. The
following items are some of the available tools provided by Altera:
■
The Quartus® II software for design, synthesis, simulation, and programming;
including integration with Qsys, simulation tools, and verification tools.
■
The Qsys system integration tool—next generation SOPC Builder that automatically
generates interconnect logic to connect intellectual property (IP) functions and
subsystems.
■
The Mentor Graphics® ModelSim®-Altera® simulation software.
■
The TimeQuest Timing Analyzer for static timing analysis with support for Synopsys®
Design Constraints (SDC) format.
■
The PowerPlay Power Analyzer for power analysis and optimization.
■
The SignalProbe and SignalTap II Logic Analyzer debugging tools.
■
The External Memory Interface Toolkit available in the Quartus II software.
■
The Transceiver Toolkit for real-time validation of transceiver link signal integrity.
For more information, visit the following pages on the Altera website:
■
Design Tools & Services
■
Design Software Support
■
Transceiver Toolkit
For a guideline to migrate from SOPC Builder to Qsys, refer to AN 632: SOPC Builder to
Qsys Migration Guidelines.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Design Specifications
Page 3
Table 1. Prerequisites Checklist (Part 2 of 2)
No. v Checklist items
4.

Review available IP
Altera and its third-party IP partners offer a large selection of parameterized blocks of IP
cores optimized for Altera devices that you can implement to reduce your
implementation and verification time.
Based on your estimated requirements, refer to the All Intellectual Property page on
Altera’s website to check if there are available IP that can provide the functions that you
need.
Design Specifications
Typically, the FPGA is an important part of the overall system and affects the rest of
the system design. Use the following checklist to start your design process.
Table 2. Design Specifications Checklist (Part 1 of 2)
No. v Checklist items
1.

Create detailed design specifications
Before you create your logic design or complete your system design, perform the
following:
2.

■
Specify the I/O interfaces for the FPGA
■
Identify the different clock domains
■
Include a block diagram of basic design functions
■
Consider a common design directory structure—if your design includes multiple
designers, a common design directory structure eases the design integration stages.
Create detailed functional verification or test plan
A functional verification plan ensures the team knows how to verify the system. Creating
a test plan at an early stage helps you design for testability and manufacturability.
For example, if you plan to perform built-in-self test (BIST) functions to drive interfaces,
you can plan to use a UART interface with a Nios® II processor inside the FPGA device.
For more information, refer to “Review available on-chip debugging tools” on page 10.
3.

Select IP that affects system design, especially I/O interfaces
Include intellectual property (IP) blocks in your detailed design specifications. Taking the
time to create these specifications improves design efficiency.
For a list of available IP offered by Altera and third-party IP partners, refer to the All
Intellectual Property page on Altera’s website.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 4
Device Selection
Table 2. Design Specifications Checklist (Part 2 of 2)
No. v Checklist items
4.

Ensure your board design supports the OpenCore Plus tethered mode
You can program your FPGA and verify your design in hardware before you purchase an
IP license by using the OpenCore Plus feature available for many IP cores. OpenCore
Plus supports the following modes:
5.

■
Untethered—your design runs for a limited time.
■
Tethered—your design runs for the duration of the hardware evaluation period. This
mode requires an Altera download cable connected to the JTAG port on your board
and a host computer that runs the Quartus II Programmer. If you plan to use this
mode, ensure that your board design supports this mode.
Review available system development tools
For more information, visit the following pages on the Altera website:
■
Design Tools & Services
■
Design Software Support
Device Selection
Use the following checklist to determine the device variant, density, and package
combination that is suitable for your design.
Table 3. Device Selection Checklist (Part 1 of 3)
No. v Checklist items
1.

Consider the available device variants
The Arria V and Cyclone V device families consist of several device variants that are
optimized for different application requirements.
Select a device based on transceivers, I/O pin count, LVDS channels, package offering,
logic/memory/multiplier density, PLLs, clock routing, and speed grade.
For more information, refer to the following documents:
2.

■
Arria V Device Overview
■
Cyclone V Device Overview
Estimate the required logic, memory, and multiplier density
Arria V or Cyclone V devices offer a range of densities that provide different amounts of
device logic resources. Determining the required logic density can be a challenging part
of the design planning process. Devices with more logic resources can implement larger
and potentially more complex designs but generally have a higher cost. Smaller devices
have lower static power utilization.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Device Selection
Page 5
Table 3. Device Selection Checklist (Part 2 of 3)
No. v Checklist items
3.

Consider vertical device migration availability and requirements
Determine whether you want the flexibility of migrating your design to another device
density. Choose your device density and package to accommodate any possible future
device migration to allow flexibility when the design nears completion.
To verify the pin migration compatibility, use the Pin Migration View window in the
Quartus II software Pin Planner. The Pin Migration View window helps you identify the
difference in pins that can exist between migration devices:
■
If one device has pins for connection to VCC or GND but are I/O pins on a different
device, the Quartus II software ensures these pins are not used for I/O. For migration,
ensure that these pins are connected to the correct PCB plane.
■
If you are migrating between two devices in the same package, connect the pins that
are not connected to the smaller die to VCC or GND on the larger die in your original
design.
For more information about verifying the pin migration compatibility, refer to the “I/O
Management” chapter of the Quartus II Handbook.
4.

Review resource utilization reports of similar designs
If you have other designs that target an Altera device, you can use their resource
utilization as an estimate for your new design. Coding style, device architecture, and
optimization options used in the Quartus II software can significantly affect resource
utilization and timing performance of a design.
To estimate resource utilization for certain configurations of Altera’s IP designs, refer to
the relevant Altera megafunctions and IP MegaCores user guides at the IP and
Megafunctions page on the Altera website.
5.

Reserve device resources for future development and debugging
Select a device that meets your design requirements with some safety margin in case
you want to add more logic later in the design cycle, upgrade, or expand your design.
You may also want additional space in the device to ease design floorplan creation for an
incremental or team-based design.
Consider reserving resources for debugging, as described in “Consider the guidelines to
plan for debugging tools” on page 10.
6.

Estimate the number of I/O pins that you require
Determine the required number of I/O pins for your application, considering the design’s
interface requirements with other system blocks. You can compile any existing designs
in the Quartus II software to determine how many I/O pins are used.
Other factors can also affect the number of I/O pins required for a design, including
simultaneous switching noise (SSN) concerns, pin placement guidelines, pins used as
dedicated inputs, I/O standard availability for each I/O bank, differences between I/O
standards and speed for row and column I/O banks, and package migration options.
For more details about choosing pin locations, refer to relevant topics under “Board
Design” on page 7 and “I/O and Clock Planning” on page 20.
7.

Consider the I/O pins you need to reserve for debugging
Consider reserving I/O pins for debugging, as described in “Consider the guidelines to
plan for debugging tools” on page 10.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 6
Device Selection
Table 3. Device Selection Checklist (Part 3 of 3)
No. v Checklist items
8.

Verify that the number of LVDS channels are enough
Larger densities and package pin counts offer more full-duplex LVDS channels for
differential signaling. Ensure that your device density-package combination includes
enough LVDS channels.
9.

Verify the number of PLLs and clock routing resources
Verify that your chosen device density package combination includes enough PLLs and
clock routing resources for your design. GCLK resources are shared between certain
PLLs, which can affect the inputs that are available for use.
For more details and references regarding clock pins and global routing resources, refer
to “I/O and Clock Planning” on page 20.
10.

Determine the device speed grade that you require
The device speed grade affects the device timing performance and timing closure, as
well as power utilization. One way to determine which speed grade your design requires
is to consider the supported clock rates for specific I/O interfaces.
For information about supported clock rates for memory interfaces using I/O pins on
different sides of the device in different device speed grades, use the estimator tool on
the External Memory Interface Spec Estimator page.
You can use the fastest speed grade while prototyping to reduce compilation time
because less time is spent optimizing the design to meet timing requirements. If the
design meets the timing requirements, you can then move to a slower speed grade for
production to reduce cost.
For information about the available speed grades, refer to the following documents:
Arria V and Cyclone V Design Guidelines
■
Arria V Device Datasheet
■
Cyclone V Device Datasheet
January 2013
Altera Corporation
Board Design
Page 7
Board Design
Use the checklists in this section as guidelines to design your board.
Early Board Design
Early planning allows the FPGA team to provide early information to PCB board and
system designers.
Table 4. Early Board Design Planning Checklist (Part 1 of 5)
No. v Checklist items
1.

Review the available configuration schemes
You can configure the Arria V or Cyclone V devices with one of several configuration
schemes.
For the list of available configuration schemes for each device family, refer to the
“Enhanced Configuration and Configuration via Protocol” sections in the following
documents:
2.

■
Arria V Device Overview
■
Cyclone V Device Overview
Select a configuration scheme
For information about the configuration schemes, the execution of the required
configuration schemes, and the necessary and optional pin settings, including the MSEL
pin settings, refer to the following documents:
■
Configuration, Design Security, and Remote System Upgrades in Arria V Devices
■
Configuration, Design Security, and Remote System Upgrades in Cyclone V Devices
For more information about selecting the configuration schemes, refer to the
Configuring Altera FPGAs document.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 8
Board Design
Table 4. Early Board Design Planning Checklist (Part 2 of 5)
No. v Checklist items
3.

Consider the configuration device support and availability
■
All configuration schemes use a configuration device, a download cable, or an
external controller (for example, a MAX® II device or microprocessor). For the active
serial (AS) configuration scheme, you can use the Altera serial configuration devices
(EPCS) and quad-serial configuration devices (EPCQ).
■
The Quartus II programmer supports configuration of devices directly using PS or
JTAG interfaces with the USB-Blaster™, EthernetBlaster II, or the ByteBlaster™ II
download cable. You can download design changes directly to the device and use the
same download cable to program configuration devices on the board, and use JTAG
debugging tools such as the SignalTap™ II Embedded Logic Analyzer.
■
Serial configuration devices do not directly support the JTAG interface but you can
program the device with JTAG download cables using the Serial FlashLoader (SFL)
feature in the Quartus II software. This feature uses the FPGA as a bridge between the
JTAG interface and the configuration device, allowing both devices to use the same
JTAG interface. However, programming the EPCS using the SFL solution is slower
than standard AS interface because it must configure the FPGA before programming
EPCS or EPCQ configuration devices.
■
If your system contains common flash interface (CFI) flash memory, you can use it
for device configuration storage. You can program CFI flash memory devices through
the JTAG interface with the parallel flash loader (PFL) megafunction in MAX II and
MAX V devices. The PFL can also control configuration from the flash memory device
to the Arria V or Cyclone V device and it supports data compression. PS and FPP
configuration modes are supported using PFL.
■
Alternatively, you can use the Altera programming unit (APU), supported third-party
programmers such as BP Microsystems and System General, or a microprocessor
with the SRunner software driver—a software driver developed for embedded serial
configuration device programming that designers can customize to fit in different
embedded systems.
For a list of documents about configuration devices, including the SRunner software and
Altera download cables, refer to the Configuration Devices page on the Altera website.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Board Design
Page 9
Table 4. Early Board Design Planning Checklist (Part 3 of 5)
No. v Checklist items
4.

Ensure the configuration scheme and board support the required features:
■
Data decompression—if you enable data compression, the storage requirement and
the time to transmit the configuration bitstream are reduced. The DCLK to DATA ratio
changes accordingly, based on the selected FPP configuration scheme. For
successful configuration, the configuration controller must send the DCLK that meets
the DCLK to DATA ratio.
■
Design security—this feature utilizes a 256-bit security key. The devices can decrypt
configuration bitstreams using the AES algorithm that is FIPS-197 certified. Design
security is available for the FPP, AS, or PS configuration schemes but not available for
the JTAG configuration scheme.
■
Remote system upgrade—this feature is supported only in the single-device AS
configuration scheme with EPCS and EPCQ devices. To implement the remote system
upgrade interface, use the ALTREMOTE_UPDATE megafunction.
■
SEU mitigation—dedicated circuitry in the devices perform cyclic redundancy check
(CRC) error detection and optionally check for SEU errors automatically. To detect
SEU errors, use the CRC_ERROR pin to flag errors and design your system to take
appropriate action. If you do not enable the CRC error detection feature, you can also
use the CRC_ERROR pin as a design I/O pin.
For more information, refer to the following documents:
5.

■
Configuration, Design Security, and Remote System Upgrades in Arria V Devices
■
Configuration, Design Security, and Remote System Upgrades in Cyclone V Devices
■
Remote System Upgrade (ALTREMOTE_UPDATE) Megafunction User Guide
■
SEU Mitigation in Arria V Devices
■
SEU Mitigation in Cyclone V Devices
Plan for support of optional configuration pins (CLKUSR and INIT_DONE), if required
You can enable the following optional configuration pins:
6.

■
CLKUSR—the Enable user-supplied start-up clock (CLKUSR) option allows you to
select the clock source to use for initialization: the internal oscillator or an external
clock provided on the CLKUSR pin. CLKUSR also allow you to drive the AS
configuration clock (DCLK) at 125 MHz maximum. In the Quartus II software, enable
this feature in the Configuration page of the Device and Pins Option dialog box.
■
INIT_DONE—you can monitor the INIT_DONE pin to check if the device has
completed initialization and is in user mode. The INIT_DONE pin is an open drain
output and requires an external pull-up to VCCPGM. During reset, after the device exits
POR and in the beginning of configuration, the INIT_DONE pin is tri-stated and pulled
high by the external pull-up resistor. To enable the INIT_DONE pin, turn on the
Enable INIT_DONE output option.
Plan for the Auto-restart after configuration error option
To reset the device internally by driving the nSTATUS pin low when a configuration error
occurs, enable the Auto-restart after configuration error option. The device releases its
nSTATUS pin after the reset time-out period. This behavior allows you to re-initiate the
configuration cycle. The nSTATUS pin requires an external 10-k pull-up resistor to
VCCPGM.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 10
Board Design
Table 4. Early Board Design Planning Checklist (Part 4 of 5)
No. v Checklist items
7.

Review available on-chip debugging tools
Take advantage of on-chip debugging features to analyze internal signals and perform
advanced debugging techniques.
Different debugging tools work better for different systems and different designers.
Early planning can reduce the time spent debugging, and eliminates design changes
later to accommodate your preferred debugging methodologies. Adding debug pins may
not be enough, because of internal signal and I/O pin accessibility on the device.
For more information about in-system debugging tools in the Quartus II software, refer
to the following documents:
8.

Arria V and Cyclone V Design Guidelines
■
System Debugging Tools Overview in the Quartus II Handbook
■
Virtual JTAG (sld_virtual_jtag) Megafunction User Guide
Consider the guidelines to plan for debugging tools
■
Select on-chip debugging schemes early to plan memory and logic requirements, I/O
pin connections, and board connections.
■
If you want to use SignalProbe incremental routing, the SignalTap II Embedded Logic
Analyzer, Logic Analyzer Interface, In-System Memory Content Editor, In-System
Sources and Probes, or Virtual JTAG megafunction, plan your system and board with
JTAG connections that are available for debugging.
■
Plan for the small amount of additional logic resources used to implement the JTAG
hub logic for JTAG debugging features.
■
For debugging with the SignalTap II Embedded Logic Analyzer, reserve device
memory resources to capture data during system operation.
■
Reserve I/O pins for debugging with SignalProbe or the Logic Analyzer Interface so
that you do not have to change the design or board to accommodate debugging
signals later.
■
Ensure the board supports a debugging mode where debugging signals do not affect
system operation.
■
Incorporate a pin header or micro connector as required for an external logic analyzer
or mixed signal oscilloscope.
■
To use debug tools incrementally and reduce compilation time, ensure incremental
compilation is on so you do not have to recompile the design to modify the debug
tool.
■
To use the Virtual JTAG megafunction for custom debugging applications, instantiate
it in the HDL code as part of the design process.
■
To use the In-System Sources and Probes feature, instantiate the megafunction in the
HDL code.
■
To use the In-System Memory Content Editor for RAM or ROM blocks or the
LPM_CONSTANT megafunction, turn on the Allow In-System Memory Content
Editor option to capture and update content independently of the system clock option
for the memory block in the MegaWizard Plug-In Manager.
January 2013
Altera Corporation
Board Design
Page 11
Table 4. Early Board Design Planning Checklist (Part 5 of 5)
No. v Checklist items
9.

Use the PowerPlay Early Power Estimator (EPE) to estimate power supplies and cooling
solution
FPGA power consumption depends on logic design and is challenging to estimate
during early board specification and layout. However, it is an important design
consideration and must be estimated accurately to develop an appropriate power budget
to design the power supplies, voltage regulators, decoupling capacitors, heat sink, and
cooling system.
Use the Altera PowerPlay EPE spreadsheet to estimate power, current, and device
junction temperature before your have a complete design. The EPE calculates the
estimated information based on device information, planned device resources, operating
frequency, toggle rates, ambient temperature, heat sinks information, air flow, board
thermal model, and other environmental considerations.
■
If you have an existing or partially-completed and compiled design—use the
Generate PowerPlay Early Power Estimator File command in the Quartus II
software to provide input to the EPE spreadsheet.
■
If you do not have an existing design—estimate manually the number of device
resources used in your design and input into the EPE spreadsheet. If the device
resources information changes during or after the design phase, your power
estimation results will be less accurate.
For more information, the EPE user guide, and to download the appropriate PowerPlay
EPE spreadsheet for your device, visit the PowerPlay Early Power Estimators (EPE) and
Power Analyzer page on the Altera website.
For guidelines about proper power supply design, refer to “Use PDN tool to plan for
power distribution and decoupling capacitor selection” on page 14.
10.

Review the transceiver design guidelines
The Quartus II software support models for Arria V and Cyclone V transceivers takes
into account the way designers use processors to handle data flow. In the Quartus II
software, high-speed transceivers are represented by PHY IP cores. Instead of the PHY
IP cores, the transceiver voltage, termination, and PLL settings are handled by the
Quartus II Settings File (.qsf).
For more information about the Arria V and Cyclone V transceivers, refer to the following
documents:
■
Arria V Device Handbook, Volume 2: Transceivers
■
Cyclone V Device Handbook, Volume 2: Transceivers
PHY IP design is modular and uses standard interfaces. All PHY IP include an Avalon®
Memory-Mapped (Avalon-MM) interface or conduit interface to access the control and
status registers, and an Avalon Streaming (Avalon-ST) interface to connect to the MAC
layer design for data transfer. For more information, refer to the following documents:
■
Altera Transceiver PHY IP Core User Guide
■
Avalon Interface Specifications
For a description of the requirements for simulating a transceiver design using the
custom PHY IP core, moving to a design, and how to change settings in the .qsf, refer to
the “Appendix: Stratix® V Transceiver Design Guidelines” section in the Stratix V Device
Design Guidelines. The guidelines in the document are applicable to the Arria V and
Cyclone V transceivers.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 12
Board Design
Power Pin Connections
The Arria V and Cyclone V devices require various voltage supplies depending on
your design requirements. Use the following checklist to design the board for the
FPGA power pin connections.
Table 5. Power Pin Connections Checklist (Part 1 of 3)
No. v Checklist items
1.

Design the board for power-up
The Arria V and Cyclone V devices support hot socketing (hot plug-in/hot swap) and
power sequencing without the use of external devices. Consider the following
guidelines:
■
The output buffers are tri-stated with weak pull-up resistors enabled until the device
is configured and configuration pins drive out.
■
Design the voltage power supply ramps to be monotonic—ensure that the minimum
current requirement for the power-on-reset (POR) supplies is available during device
power up. If the following voltages share the same power supply and there is not
enough current available during power up, these results apply:
■
VCCIO, VCCPD, and VCCPGM—the devices do not enter POR
■
VCCIO and VCCPD—the devices do not exit POR
■
Set the POR delay to ensure power supplies are stable—use the MSEL pin settings to
select between a typical POR delay of 4 ms or 100 ms. In both cases, you can extend
the POR delay by using an external component to assert the nSTATUS pin low. To
ensure the device configures properly and enters user mode, extend the POR delay if
the board cannot meet the maximum power ramp time specifications.
■
For the device to exit POR, you must power the VCCBAT power supply even if you do
not use the volatile key.
■
Design power sequencing and voltage regulators for the best device reliability—
although power sequencing is not required for correct operation, consider the
power-up timing of each rail to prevent problems with long-term device reliability if
you are designing a multi-rail powered system.
■
Connect the GND between boards before connecting the power supplies—Altera uses
GND as a reference for hot-socketing operations and I/O buffer designs. Connecting
the GND between boards before connecting the power supplies prevents the GND on
your board from being pulled up inadvertently by a path to power through other
components on your board. A pulled up GND could otherwise cause an
out-of-specification I/O voltage or current condition with the device.
For more information, refer to the following documents:
Arria V and Cyclone V Design Guidelines
■
Power Management in Arria V Devices
■
Power Management in Cyclone V Devices
■
Arria V Device Family Pin Connection Guidelines
■
Cyclone V Device Family Pin Connection Guidelines
■
Configuration, Design Security, and Remote System Upgrades in Arria V Devices
■
Configuration, Design Security, and Remote System Upgrades in Cyclone V Devices
January 2013
Altera Corporation
Board Design
Page 13
Table 5. Power Pin Connections Checklist (Part 2 of 3)
No. v Checklist items
2.

Review the list of required supply voltages
For a list of the required supply voltages and the recommended operating conditions,
refer to the following documents:
3.

■
Arria V Device Datasheet
■
Cyclone V Device Datasheet
Ensure I/O power pin compatibility with I/O standards
The output pins of the devices will not conform to the I/O standard specifications if the
VCCIO level is out of the recommended operating range of the I/O standard.
For a complete list of the supported I/O standards and VCCIO voltages, refer to the
following documents:
4.

■
I/O Features in Arria V Devices
■
I/O Features in Cyclone V Devices
Ensure correct power pin connections
■
5.
January 2013
Altera Corporation

Connect all power pins correctly as specified in the following documents:
■
Arria V Device Family Pin Connection Guidelines
■
Cyclone V Device Family Pin Connection Guidelines
■
Connect VCCIO pins and VREF pins to support the I/O standards of each bank.
■
For unused supplies, consider whether there is a need to ground, open, or retain the
power connection.
Determine power rail sharing
■
Explore unique requirements for FPGA power pins or other power pins on your
board, and determine which devices on your board can share a power rail. It is
especially important for you to consider the power supply sharing ability of devices
from different device families.
■
Follow the suggested power supply sharing and isolation guidance, and the specific
guidelines for each pin in the following documents:
■
Arria V Device Family Pin Connection Guidelines
■
Cyclone V Device Family Pin Connection Guidelines
■
AN 583: Designing Power Isolation Filters with Ferrite Beads for Altera FPGAs
Arria V and Cyclone V Design Guidelines
Page 14
Board Design
Table 5. Power Pin Connections Checklist (Part 3 of 3)
No. v Checklist items
6.

Use PDN tool to plan for power distribution and decoupling capacitor selection
Arria V and Cyclone V devices include embedded on-package and on-die decoupling
capacitors to provide high-frequency decoupling.
To plan power distribution and return currents from the voltage regulating module
(VRM) to the FPGA power supplies, you can use the power distribution network (PDN)
design tool that optimizes the board-level PDN graphically. Although you can use SPICE
simulation to simulate the circuit, the PDN design tool provides a fast, accurate, and
interactive way to determine the right number of decoupling capacitors for optimal cost
and performance trade-off.
Download the appropriate PDN tool and documentation from the Altera website:
7.

■
Power Delivery Network (PDN) Tool Version 12.0 for Arria V, Cyclone V, Cyclone IV,
and Arria II GZ Devices
■
AN 574: Printed Circuit Board (PCB) Power Delivery Network (PDN) Design
Methodology
■
Device-Specific Power Delivery Network (PDN) Tool User Guide
■
Power Delivery Network (PDN) Tool User Guide (device agnostic)
Review the following guidelines for PLL board design
■
■
8.

Connect all PLL power pins to reduce noise even if the design does not use all the
PLLs. For pin voltage requirements, refer to the following documents:
■
Arria V Device Family Pin Connection Guidelines
■
Cyclone V Device Family Pin Connection Guidelines
Power supply nets should be provided by an isolated power plane, a power plane cut
out, or a thick trace.
Review the transceiver design guidelines
For more information about the Arria V and Cyclone V transceivers, refer to the following
documents:
■
Arria V Device Handbook, Volume 2: Transceivers
■
Cyclone V Device Handbook, Volume 2: Transceivers
■
Altera Transceiver PHY IP Core User Guide
■
Avalon Interface Specifications
For a description of the requirements for simulating a transceiver design using the
custom PHY IP core, moving to a design, and how to change settings in the .qsf, refer to
the “Appendix: Stratix V Transceiver Design Guidelines” section in the Stratix V Device
Design Guidelines. The guidelines in the document are applicable to the Arria V and
Cyclone V transceivers.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Board Design
Page 15
Configuration Pin Connections
Depending on your configuration scheme, different pull-up or pull-down resistor,
signal integrity, and specific pin requirements apply. Connecting the configurations
pins correctly is important. Use the following checklist to address common issues.
Table 6. Configuration Pin Connections Checklist (Part 1 of 3)
No. v Checklist items
1.

Verify configuration pin connections and pull-up or pull-down resistors are correct for
your configuration schemes
For specifics about each configuration pin, refer to the following documents:
2.
3.


■
Arria V Device Family Pin Connection Guidelines
■
Cyclone V Device Family Pin Connection Guidelines
Design configuration DCLK and TCK pins to using the same technique as in designing
high-speed signal or system clock
■
Noise on the TCK signal can affect JTAG configuration.
■
Noisy DCLK signal can affect configuration and cause a CRC error.
■
For a chain of devices, noise on the TCK or DCLK pins in the chain can cause JTAG
programming or configuration to fail for the entire chain.
Verify the JTAG pins are connected to a stable voltage level if not in use
JTAG configuration takes precedence over all configuration methods. If you do not use
the JTAG interface, do not leave the JTAG pins floating or toggling during configuration.
4.

Verify the JTAG pin connections to the download cable header
A device operating in JTAG mode uses the required TDI, TDO, TMS, and TCK pins, and
the optional TRST pin. The TCK pin has an internal weak pull-down resistor. The TDI,
TMS, and TRST pins have weak internal pull-up resistors. The JTAG output pin (TDO) and
all JTAG input pins are powered by the 2.5 or 3.0-V VCCPD.
5.
January 2013
Altera Corporation

Review the following JTAG pin connections guidelines:
■
If you have multiple devices in the chain, connect the TDO pin of a device to the TDI
pin of the next device in the chain.
■
Noise on the JTAG pins during configuration, user mode, or power-up can cause the
device to go into an undefined state or mode.
■
To disable the JTAG state machine during power-up, pull the TCK pin low through a
1-k resistor to ensure that an unexpected rising edge does not occur on TCK.
■
Pull TMS and TDI high through a 1-k to 10-k resistor.
■
Connect TRST directly to VCCPD. Connecting the pin low disables the JTAG circuitry.
Arria V and Cyclone V Design Guidelines
Page 16
Board Design
Table 6. Configuration Pin Connections Checklist (Part 2 of 3)
No. v Checklist items
6.

Ensure the download cable and JTAG pin voltages are compatible
The download cable interfaces with the JTAG pins of your device. The operating voltage
supplied to the Altera download cable by the target board through the 10-pin header
determines the operating voltage level of the download cable. The JTAG pins are
powered by VCCPD.
In a JTAG chain containing devices with different VCCIO levels, the devices with a higher
VCCIO level should drive the devices with the same or lower VCCIO level. A one-level shifter
is required at the end of the chain with this device arrangement. If this arrangement is
not possible, you have to add more level shifters into the chain.
For recommendations about connecting a JTAG chain with multiple voltages across the
devices in the chain, refer to the following documents:
7.
8.


■
JTAG Boundary-Scan Testing in Arria V Devices
■
JTAG Boundary-Scan Testing in Cyclone V Devices
Buffer the JTAG signal according to the following guidelines:
■
If a cable drives three or more devices, buffer the JTAG signal at the cable connector
to prevent signal deterioration.
■
Anything added to the board that affects the inductance or capacitance of the JTAG
signals increases the likelihood that a buffer should be added to the chain.
■
Each buffer should drive no more than eight loads for the TCK and TMS signals, which
drive in parallel. If jumpers or switches are added to the path, decrease the number of
loads.
Ensure all devices in the chain are connected properly
If your device is in a configuration chain, ensure all devices in the chain are connected
properly.
9.
10.


Ensure that the MSEL pins are not left floating and do not use weak pull-up resistors
■
Connect the MSEL pins directly to the power or GND planes.
■
If you are using pull-up or pull-down resistors, use 0- resistors.
■
If the MSEL pins are floating or weakly pulled, you may not be able to configure the
device.
Review the following guidelines for other configuration pins:
■
Arria V and Cyclone V Design Guidelines
Hold the nCE (chip enable) pin low during configuration, initialization, and user mode:
■
In single device configuration or JTAG programming—tie nCE low
■
In multi-device configuration chain—tie nCE low on the first device and connect
the nCEO pin of the first device to the nCE pin of the next device
January 2013
Altera Corporation
Board Design
Page 17
Table 6. Configuration Pin Connections Checklist (Part 3 of 3)
No. v Checklist items
11.

Determine if you need to turn on device-wide output enable
The Arria V or Cyclone V device support an optional chip-wide output enable that allows
you to override all tri-states on the device I/Os. When the DEV_OE pin is driven low, all
I/O pins are tri-stated; when this pin is driven high, all pins behave as programmed.
To use the chip-wide output enable feature:
■
Turn on Enable device-wide output enable (DEV_OE) under the General category of
the Device and Pin Options dialog box in the Quartus II software before compiling
your design
■
Ensure that the DEV_OE pin is driven to a valid logic level on your board
■
Do not leave the DEV_OE pin floating
General I/O Pin Connections
Use the following checklist to plan your general I/O pin connections and to improve
signal integrity.
Table 7. General I/O Pin Connections Checklist (Part 1 of 4)
No. v Checklist items
1.
January 2013
Altera Corporation

Specify the state of unused I/O pins according to the following guidelines:
■
To reduce power dissipation, set clock pins and other unused I/O pins As inputs
tri-stated. By default, the Quartus II software set the input pins tri-stated with weak
pull-up resistor enabled.
■
To improve signal integrity, in the Reserve all unused pins option under the Unused
Pins category of the Device and Pin Options dialog box of the Quartus II software,
set the unused pins As output driving ground. This setting reduces inductance by
creating a shorter return path and reduces noise on the neighboring I/Os. However,
do not use this approach if it results in many via paths that causes congestion for
signals under the device.
■
Carefully check the pin connections in the pin report file (.pin) generated by the
Quartus II software when you compile your design. The .pin specifies how you
should connect the device pins. I/O pins specified as GND can be left unconnected or
connected to ground for improved noise immunity. Do not connect RESERVED pins.
Arria V and Cyclone V Design Guidelines
Page 18
Board Design
Table 7. General I/O Pin Connections Checklist (Part 2 of 4)
No. v Checklist items
2.

Refer to the Board Design Resource Center
If your design has high-speed signals, especially with Arria V or Cyclone V high-speed
transceivers, the board design has a major impact on the signal integrity in the system.
For detailed information about signal integrity and board design, refer to the Board
Design Resource Center on the Altera website.
For example, Altera provides the following application notes that offer information about
high-speed board stack-up and signal routing layers:
■
AN 528: PCB Dielectric Material Selection and Fiber Weave Effect on High-Speed
Channel Routing
■
AN 529: Via Optimization Techniques for High-Speed Channel Designs
■
AN 530: Optimizing Impedance Discontinuity Caused by Surface Mount Pads for
High-Speed Channel Designs
You can also refer to the I/O Management, Board Development Support, and Signal
Integrity Analysis Resource Center on the Altera website for board-level signal integrity
information related to the Quartus II software.
3.

Design VREF pins to be noise free
Voltage deviation on a VREF pin can affect the threshold sensitivity for inputs. For more
information about VREF pins and I/O standards, refer to “I/O Features and Pin
Connections” on page 21.
4.

Refer to the Board Design Guideline Solution Center
Noise generated by SSN—when too many pins in close proximity change voltage levels
at the same time—can reduce the noise margin and cause incorrect switching. For
example, consider these board layout recommendations:
■
Break out large bus signals on board layers close to the device to reduce cross talk.
■
If possible, route traces orthogonally if two signal layers are next to each other, and
use a separation of two to three times the trace width.
For more board layout recommendations that can help with noise reduction, refer to the
PCB guidelines in the Board Design Guidelines Solution Center on the Altera website.
For a list of recommendations for I/O and clock connections, refer to “I/O Simultaneous
Switching Noise” on page 29.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Board Design
Page 19
Table 7. General I/O Pin Connections Checklist (Part 3 of 4)
No. v Checklist items
5.

Verify I/O termination and impedance matching
Voltage-referenced I/O standards require both a VREF and a termination voltage (VTT).
The reference voltage of the receiving device tracks the termination voltage of the
transmitting device. Consider the following items:
■
Each voltage-referenced I/O standard requires a unique termination setup. For
example, a proper resistive signal termination scheme is critical in SSTL-2 standards
to produce a reliable DDR memory system with superior noise margin.
■
Although single-ended, non-voltage-referenced I/O standards do not require
termination, impedance matching is necessary to reduce reflections and improve
signal integrity.
■
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 signal line. Arria V and Cyclone V devices provide an optional
differential on-chip resistor when using LVDS.
The Arria V and Cyclone V on-chip series and parallel termination provides the
convenience of no external components. You can also use external pull-up resistors to
terminate the voltage-referenced I/O standards such as SSTL and HSTL.
For a complete list of on-chip termination (OCT) support for each I/O standard, refer to
the following documents:
6.

■
I/O Features in Arria V Devices
■
I/O Features in Cyclone V Devices
Perform full board routing simulation using IBIS models
To ensure that the I/O signaling meets receiver threshold levels on your board setup,
perform full board routing simulation with third-party board-level simulation tools using
an IBIS model.
To select the IBIS output in the Quartus II software, on the Assignments menu, click
Settings. Navigate to the Board-Level page of the EDA Tool Settings category. Under
the Board-level signal integrity analysis section, in the Format option, select IBIS.
For more information, refer to the Signal Integrity Analysis with Third-Party Tools
chapter of the Quartus II Handbook.
7.

Configure board trace models for Quartus II advanced timing analysis
The signal integrity and board routing propagation delay is important for you to design
proper system operation. If you use and FPGA with high-speed interfaces in your board
design, analyze the board level timing as part of the I/O and board planning.
To generate a more accurate I/O delays and extra reports to gain better insights into the
signal behavior at the system level, turn on Enable Advanced I/O Timing under the
TimeQuest Timing Analyzer category in the Settings dialog box of your Quartus II
project. With this option turned on, the TimeQuest Timing Analyzer uses simulation
results for the I/O buffer, package, and board trace model to generate the I/O delays.
You can use the advanced timing reports as a guide to make changes to the I/O
assignments and board design to improve timing and signal integrity.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 20
I/O and Clock Planning
Table 7. General I/O Pin Connections Checklist (Part 4 of 4)
No. v Checklist items
8.

Review your pin connections
Altera provides schematic review worksheets based on the device Pin Connection
Guidelines and other board-level pin connections literature that you need to consider
when you finalize your schematics.
Use the following worksheets to help you find mistakes in your schematic and adhere to
Altera’s guidelines:
■
Arria V Device Schematic Review Worksheet
■
Cyclone V Schematic Review Worksheet
I/O and Clock Planning
Use the checklists in this section as guidelines to plan your I/O and clocking.
Early Pin Planning and I/O Assignment Analysis
In many design environments, FPGA designers want to plan top-level FPGA I/O pins
early so that board designers can start developing the PCB design and layout.
Table 8. Early Pin Planning and I/O Assignment Analysis Checklist (Part 1 of 2)
No. v Checklist items
1.

Verify pin locations in the FPGA place-and-route software early
The FPGA I/O capabilities and board layout guidelines influence pin locations and other
types of assignments. Starting FPGA pin planning early improves the confidence in early
board layouts, reduces the chance of error, and improves the overall time-to-market.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
I/O and Clock Planning
Page 21
Table 8. Early Pin Planning and I/O Assignment Analysis Checklist (Part 2 of 2)
No. v Checklist items

2.
Use the Quartus II Pin Planner for I/O pin planning, assignment, and validation
Early in the design process, the system architect typically has information about the
standard I/O interfaces (such as memory and bus interfaces), IP cores to be used in the
design, and any other I/O-related assignments defined by system requirements.
You can use the Quartus II Pin Planner for I/O pin assignment planning, assignment, and
validation:
■
The Quartus II Start I/O Assignment Analysis command checks that the pin locations
and assignments are supported in the target FPGA architecture. Checks include
reference voltage pin usage, pin location assignments, and mixing of I/O standards.
■
You can use I/O Assignment Analysis to validate I/O-related assignments that you
make or modify throughout the design process.
■
The Create/Import Megafunction feature of the Pin Planner interfaces with the
MegaWizard Plug-In Manager, and enables you to create or import custom
megafunctions and IP cores that use I/O interfaces.
■
Enter PLL and LVDS blocks, including options such as dynamic phase alignment
(DPA) because the options affect the pin placement rules. Then, use the Create TopLevel Design File command to generate a top-level design netlist file.
■
You can use the I/O analysis results to change pin assignments or IP parameters and
repeat the checking process until the I/O interface meets your design requirements
and passes the pin checks in the Quartus II software.
■
You can create a transceiver instance together with its interface and check the
transceiver pin or bank placement.
After planning is complete, you can pass the preliminary pin location information to PCB
designers.
After the design is complete, you can use the reports and messages generated by the
Quartus II Fitter for the final sign-off of the pin assignments.
For more information about I/O assignment and analysis, refer to the I/O Management
chapter of the Quartus II Handbook.
I/O Features and Pin Connections
Use the checklist in this section for guidelines related to I/O features and pin
connections:
■
Support for different I/O signal types and I/O standards in device I/O banks, and
other I/O features available for your design
■
Information about memory interfaces, pad placement guidelines, and special pin
connections
f For a list of I/O pin locations and connection guidelines, refer to the following
documents:
■
January 2013
Arria V Device Family Pin Connection Guidelines
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 22
I/O and Clock Planning
■
Cyclone V Device Family Pin Connection Guidelines
Table 9. I/O Features and Pin Connections Checklist (Part 1 of 5)
No. v Checklist items
1.
2.
3.
4.




Determine if your system requires single-ended I/O signaling
■
Single-ended I/O signaling provides a simple rail-to-rail interface.
■
The speed is limited by the large voltage swing and noise.
■
Single-ended I/Os do not require termination, unless reflection in the system causes
undesirable effects.
Determine if your system requires voltage-referenced signaling
■
Voltage-referenced signaling reduces the effects of simultaneous switching outputs
(SSO) from pins changing voltage levels at the same time (for example, external
memory interface data and address buses).
■
Voltage-referenced signaling provides an improved logic transition rate with a
reduced voltage swing, and minimizes noise caused by reflection with a termination
requirement.
■
Additional termination components are required for the reference voltage source
(VTT).
Determine if your system requires differential signaling
■
Differential signaling eliminates the interface performance barrier of single-ended and
voltage-referenced signaling, with superior speed using an additional inverted
closely-coupled data pair.
■
Differential signaling avoids the requirement for a clean reference voltage. This is
possible because of lower swing voltage and noise immunity with a common mode
noise rejection capability.
■
Considerations for this implementation include the requirements for a dedicated PLL
to generate a sampling clock, and matched trace lengths to eliminate the phase
difference between an inverted and non-inverted pair.
■
Allow the software to assign locations for the negative pin in differential pin pairs.
Select a suitable signaling type and I/O standard for each I/O pin
Ensure that the appropriate I/O standard support is supported in the targeted I/O bank.
For more information, refer to the following documents:
5.

Arria V and Cyclone V Design Guidelines
■
I/O Features in Arria V Devices
■
High-Speed Differential I/O Interfaces and DPA in Arria V Devices
■
I/O Features in Cyclone V Devices
Place I/O pins that share voltage levels in the same I/O bank
■
Certain I/O banks on support different I/O standards and voltage levels.
■
You can assign I/O standards and make other I/O-related settings in the Pin Planner.
■
Use the correct dedicated pin inputs for signals such as clocks and global control
signals.
January 2013
Altera Corporation
I/O and Clock Planning
Page 23
Table 9. I/O Features and Pin Connections Checklist (Part 2 of 5)
No. v Checklist items
6.
7.
8.



Verify that all output signals in each I/O bank are intended to drive out at the bank's
VCCIO voltage level
■
The board must supply each bank with one VCCIO voltage level for every VCCIO pin in
a bank.
■
Each I/O bank is powered by the VCCIO pins of that particular bank and is
independent of the VCCIO of other I/O banks.
■
A single I/O bank supports output signals that are driving at the same voltage as the
VCCIO.
■
An I/O bank can simultaneously support any number of input signals with different
I/O standards.
Verify that all voltage-referenced signals in each I/O bank are intended to use the bank's
VREF voltage
■
To accommodate voltage-referenced I/O standards, each I/O bank supports multiple
VREF pins feeding a common VREF bus. Set the VREF pins to the correct voltage for
the I/O standards in the bank.
■
Each I/O bank can only have a single VCCIO voltage level and a single VREF voltage
level at a given time. If the VREF pins are not used as voltage references, the pins
cannot be used as generic I/O pins and must be tied to the VCCIO of that same bank or
GND.
■
An I/O bank, including single-ended or differential standards, can support
voltage-referenced standards as long as all voltage-referenced standards use the
same VREF setting.
■
For performance reasons, voltage-referenced input standards use their own VCCPD
level as the power source. You can place voltage-referenced input signals in a bank
with a VCCIO of 2.5 V or below.
■
Voltage-referenced bidirectional and output signals must drive out at the VCCIO
voltage level of the I/O bank.
Check the I/O bank support for LVDS and transceiver features
Different I/O banks include different support for LVDS signaling. The Arria V and
Cyclone V transceiver banks include additional support.
For more information, refer to the following documents:
9.

■
High-Speed Differential I/O Interfaces and DPA in Arria V Devices
■
Transceiver Architecture in Arria V Devices
■
I/O Features in Cyclone V Devices
■
Transceiver Architecture in Cyclone V Devices
Verify the usage of the VREF pins that are used as regular I/Os
VREF pins have higher pin capacitance that results in a different I/O timing:
January 2013
Altera Corporation
■
Do not use these pins in a grouped interface such as a bus.
■
Do not use these pins for high edge rate signals such as clocks.
Arria V and Cyclone V Design Guidelines
Page 24
I/O and Clock Planning
Table 9. I/O Features and Pin Connections Checklist (Part 3 of 5)
No. v Checklist items
10.

Use the UniPHY megafunction (or IP core) for each memory interface, and follow
connection guidelines
The self-calibrating UniPHY megafunction is optimized to take advantage of the Arria V
or Cyclone V I/O structure. The UniPHY megafunction allows you to set external
memory interface features and helps set up the physical interface (PHY) best suited for
your system. When you use the Altera memory controller MegaCore functions, the
UniPHY megafunction is instantiated automatically.
If you design multiple memory interfaces into the device using Altera IP, generate a
unique interface for each instance to ensure good results instead of designing it once
and instantiating it multiple times.
For more information, refer to the Planning Pin and FPGA Resources chapter in the
External Memory Interface Handbook.
11.

Use dedicated DQ/DQS pins and DQ groups for memory interfaces
The data strobe DQS and data DQ pin locations are fixed in Arria V and Cyclone V
devices. Before you design your device pin-out, refer to the memory interface guidelines
for details and important restrictions related to the connections for these and other
memory related signals.
For more information about specific external memory interface topic, refer to the
following documents:
12.

■
Volume 2: Design Guidelines in the External Memory Interface Handbook
■
External Memory Interface Spec Estimator on the Altera website
■
Introduction to UniPHY IP in the External Memory Interface Handbook
■
External Memory Solutions Center on the Altera website
Make dual-purpose pin settings and check for any restrictions when using these pins as
regular I/O
You can use dual-purpose configuration pins as general I/Os after device configuration
is complete. Select the desired setting for each of the dual-purpose pins on the
Dual-Purpose Pins category of the Device and Pin Options dialog box. Depending on
the configuration scheme, these pins can be reserved as regular I/O pins, as inputs that
are tri-stated, as outputs that drive ground, or as outputs that drive an unspecified
signal.
You can also use dedicated clock inputs, which drive the GCLK networks, as general
purpose input pins if they are not used as clock pins. If you use the clock inputs as
general inputs, the I/O registers use ALM-based registers because the clock input pins
do not include dedicated I/O registers.
The device-wide reset and clear pins are available as design I/Os if they are not enabled.
For more information, refer to “Determine if you need to turn on device-wide output
enable” on page 17 and “Enable the chip-wide reset to clear all registers if required” on
page 31.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
I/O and Clock Planning
Page 25
Table 9. I/O Features and Pin Connections Checklist (Part 4 of 5)
No. v Checklist items
13.

Review available device I/O features that can help I/O interfaces
Check the available I/O features and consider the following guidelines:
■
Programmable current strength—ensure that the output buffer current strength is
sufficiently high, but does not cause excessive overshoot or undershoot that violates
voltage threshold parameters for the I/O standard. Altera recommends performing an
IBIS or SPICE simulations to determine the right current strength setting for your
specific application.
■
Programmable slew rate—confirm that your interface meets its performance
requirements if you use slower slew rates. Altera recommends performing IBIS or
SPICE simulations to determine the right slew rate setting for your specific
application.
■
Programmable input/output element (IOE) delays—helps read and time margins by
minimizing the uncertainties between signals in the bus. For delay specifications,
refer to the relevant device datasheet.
■
Open-drain output—if configured as an open-drain, the logic value of the output is
either high-Z or 0. This feature is used in system-level control signals that can be
asserted by multiple devices in the system. Typically, an external pull-up resistor is
required to provide logic high.
■
Bus hold—If the bus-hold feature is enabled, you cannot use the programmable pullup option. Disable the bus-hold feature if the I/O pin is configured for differential
signals. For the specific sustaining current driven through this resistor and the
overdrive current used to identify the next driven input and level for each VCCIO
voltage, refer to the relevant device datasheet.
■
Programmable pull-up resistors—weakly holds the I/O to the VCCIO level when in user
mode. This feature can be used with the open-drain output to eliminate the need for
an external pull-up resistor. If the programmable pull-up option is enabled, you
cannot use the bus-hold feature.
■
Programmable pre-emphasis—increases the amplitude of the high frequency
component of the output signal, and thus helps to compensate for the frequencydependent attenuation along the transmission line.
■
Programmable differential output voltage—allows you to adjust output eye height to
optimize trace length and power consumption. A higher VOD swing improves voltage
margins at the receiver end while a smaller VOD swing reduces power consumption.
For more information, refer to the following document:
January 2013
Altera Corporation
■
I/O Features in Arria V Devices
■
I/O Features in Cyclone V Devices
Arria V and Cyclone V Design Guidelines
Page 26
I/O and Clock Planning
Table 9. I/O Features and Pin Connections Checklist (Part 5 of 5)
No. v Checklist items
14.

Consider OCT features to save board space
Driver-impedance matching provides the I/O driver with controlled output impedance
that closely matches the impedance of the transmission line to significantly reduce
reflections. OCT maintains signal quality, saves board space, and reduces external
component costs.
■
OCT RS and RT are supported in the same I/O bank for different I/O standards if they
use the same VCCIO supply voltage
■
Each I/O in an I/O bank can be independently configured to support OCT RS,
programmable current strength, or OCT RT
■
You cannot configure both OCT RS and programmable current strength or slew rate
control for the same I/O buffer
■
Differential OCT RD is available in all I/O pins
For details about the support and implementation of this feature, refer to the following
documents:
■
I/O Features in Arria V Devices
■
High-Speed Differential I/O Interfaces and DPA in Arria V Devices
■
I/O Features in Cyclone V Devices
15.

Verify that the required termination scheme is supported for all pin locations
16.

Choose the appropriate mode of DPA, non-DPA, or soft-CDR for high-speed LVDS
interfaces
For more information, refer to the following documents:
■
High-Speed Differential I/O Interfaces and DPA in Arria V Devices
■
I/O Features in Cyclone V Devices
Clock Planning
The first stage in planning your clocking scheme is to determine your system clock
requirements:
■
Understand your device’s available clock resources and correspondingly plan the
design clocking scheme. Consider your requirements for timing performance, and
how much logic is driven by a particular clock.
■
Based on your system requirements, define the required clock frequencies for your
FPGA design and the input frequencies available to the FPGA. Use these
specifications to determine your PLL scheme.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
I/O and Clock Planning
Page 27
■
Use the Quartus II MegaWizard Plug-In Manager to enter your settings in Altera
PLL megafunctions, and check the results to verify whether particular features
and input/output frequencies can be implemented in a particular PLL.
Table 10. Clock Planning Checklist (Part 1 of 2)
No. v Checklist items
1.

Use the device fractional PLLs for clock management
Connect clock inputs to specific PLLs to drive specific low-skew routing networks.
Analyze the global resource availability for each PLL and the PLL availability for each
clock input pin. Use the following descriptions to help determine which clock networks
are appropriate for the clock signals in your design:
2.

■
The GCLK networks can drive throughout the entire device, serving as low-skew
clock sources for device logic. This clock region has the maximum delay compared to
other clock regions but allows the signal to reach everywhere within the device. This
option is good for routing global reset/clear signals or routing clocks throughout the
device.
■
The RCLK networks only pertain to the quadrant they drive into and provide the
lowest clock delay and skew for logic contained within a single device quadrant.
■
IOEs and internal logic can also drive GCLKs and RCLKs to create internally generated
GCLKs or RCLKs and other high fan-out control signals; for example, synchronous or
asynchronous clears and clock enables.
■
PLLs cannot be driven by internally-generated GCLKs or RCLKs. The input clock to
the PLL must come from dedicated clock input pins or from another pin/PLL-fed
GCLK or RCLK.
■
PCLK networks are a collection of individual clock networks driven from the
periphery of the device. Clock outputs from the DPA block, PLD-transceiver interface,
I/O pins, and internal logic can drive the PCLK networks. These PCLKs have higher
skew compared to GCLK and RCLK networks and can be used instead of general
purpose routing to drive signals into and out of the device.
Enable PLL features and check settings in the MegaWizard Plug-In Manager
You can configure the fractional PLLs in the Arria V and Cyclone V to function in integer
or enhanced fractional mode.
Take note that to drive LVDS channels, you must use the PLLs in integer mode.
For more information about the fractional PLL features, refer to the “Fractional PLL
Architecture” section in the following documents:
3.

■
Clock Networks and PLLs in Arria V Devices
■
Clock Networks and PLLs in Cyclone V Devices
Ensure that you select the correct PLL feedback compensation mode
Arria V and Cyclone V PLLs support six different clock feedback modes. For more
information, refer to the “Clock Feedback Modes” section in the following documents:
4.

■
Clock Networks and PLLs in Arria V Devices
■
Clock Networks and PLLs in Cyclone V Devices
Check that the PLL offers the required number of clock outputs and use dedicated clock
output pins
You can connect clock outputs to dedicated clock output pins or clock networks.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 28
I/O and Clock Planning
Table 10. Clock Planning Checklist (Part 2 of 2)
No. v Checklist items
5.

Use the clock control block for clock selection and power-down
Every GCLK and RCLK network has its own clock control block. The control block
provides the following features that you can use to select different clock input signals or
power-down clock networks to reduce power consumption without using any
combinational logic in your design:
■
Clock source selection (with dynamic selection for GCLKs)
■
GCLK multiplexing
■
Clock power down (with static or dynamic clock enable or disable)
In Arria V and Cyclone V devices, the clkena signals are supported at the clock network
level instead of at the PLL output counter level. This allows you to gate off the clock even
when you are not using a PLL. You can also use the clkena signals to control the
dedicated external clocks from the PLLs.
For more information, refer to the Clock Control Block (ALTCLKCTRL) Megafunction
User Guide.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Design Entry
Page 29
I/O Simultaneous Switching Noise
SSN is a concern when too many I/Os (in close proximity) change voltage levels at the
same time. Use the checklist in this section for recommendations to plan I/O and
clock connections.
Table 11. I/O Simultaneous Switching Noise Checklist
No. v Checklist item
1.

Consider the following recommendations to mitigate I/O simultaneous switching noise:
■
Analyze the design for possible SSN problems.
■
Reduce the number of pins that switch the voltage level at exactly the same time
whenever possible.
■
Use differential I/O standards and lower-voltage standards for high-switching I/Os.
■
Use lower drive strengths for high-switching I/Os. The default drive strength setting
might be higher than your design requires.
■
Reduce the number of simultaneously switching output pins within each bank.
Spread output pins across multiple banks if possible.
■
Spread the switching I/Os evenly throughout the bank to reduce the number of
aggressors in a given area to reduce SSN if bank usage is substantially below 100%.
■
Separate simultaneously switching pins from input pins that are susceptible to SSN.
■
Place important clock and asynchronous control signals near ground signals and
away from large switching buses.
■
Avoid using I/O pins one or two pins away from PLL power supply pins for highswitching or high-drive strength pins.
■
Use staggered output delays to shift the output signals through time, or use
adjustable slew rate settings.
For information and guidelines on using available I/O features, refer to “I/O Features and
Pin Connections” on page 21.
For signal integrity design techniques to mitigate SSN, view the Signal & Power Integrity
Design Techniques for SSN webcast on the Altera website.
Design Entry
In complex FPGA design development, design practices, coding styles, and
megafunction usage have an enormous impact on your device's timing performance,
logic utilization, and system reliability. In addition, while planning and creating the
design, plan for a hierarchical or team-based design to improve design productivity.
Table 12. Design Entry Checklist (Part 1 of 6)
No. v Checklist items
1.

Use synchronous design practices
In a synchronous design, a clock signal triggers all events. When all of the registers’
timing requirements are met, a synchronous design behaves in a predictable and reliable
manner for all process, voltage, and temperature (PVT) conditions. You can easily target
synchronous designs to different device families or speed grades.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 30
Design Entry
Table 12. Design Entry Checklist (Part 2 of 6)
No. v Checklist items
2.
3.


Consider the following recommendations to avoid clock signals problems:
■
Use dedicated clock pins and clock routing for best results—dedicated clock pins
drive the clock network directly, ensuring lower skew than other I/O pins. Use the
dedicated routing network to have a predictable delay with less skew for high fan-out
signals. You can also use the clock pins and clock network to drive control signals
like asynchronous reset.
■
For clock inversion, multiplication, and division use the device PLLs.
■
For clock multiplexing and gating, use the dedicated clock control block or PLL clock
switchover feature instead of combinational logic.
■
If you must use internally generated clock signals, register the output of any
combinational logic used as a clock signal to reduce glitches. For example, if you
divide a clock using combinational logic, clock the final stage with the clock signal
that was used to clock the divider circuit.
■
Consider the following recommendations for transceivers:
■
Use the transceiver dedicated refclk pins.
■
For easier timing closure, clock the transmit logic in the fabric using the
transmitter recovered clock, and the receive logic using the receiver recovered
clock.
Use the Quartus II Design Assistant to check design reliability
The Design Assistant is a design-rule checking tool that checks your design according to
Altera recommendations and helps you avoid design issues early in your design flow:
■
To run the tool, on the Processing menu, point to Start and click Start Design
Assistant.
■
To set the Design Assistant to run automatically during compilation, turn on Run
Design Assistant during compilation in the Settings dialog box.
You can also use third-party “lint” tools to check your coding styles.
For more information, refer to the “Checking Design Violations with the Design
Assistant” section in the Recommended Design Practices chapter of the Quartus II
Handbook.
You can also refer to industry papers for more information about multiple clock design.
For a good analysis, refer to www.sunburst-design.com/papers.
4.

Use megafunctions with the MegaWizard Plug-In Manager
Instead of coding your own logic, save your design time by using Altera’s
megafunctions—a library of parameterized modules and device-specific megafunctions.
The megafunctions are optimized for Altera device architectures and can offer more
efficient logic synthesis and device implementation.
To ensure that you set all ports and parameters correctly, use the Quartus II Megawizard
Plug-In Manager to build or change megafunctions parameters.
For detailed information about a specific megafunction, refer to the relevant user guide
on the IP and Megafunctions page at the Altera website.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Design Entry
Page 31
Table 12. Design Entry Checklist (Part 3 of 6)
No. v Checklist items
5.

Review the information on dynamic and partial reconfiguration features
The Arria V and Cyclone V devices support dynamic and partial reconfiguration:
■
Dynamic reconfiguration—dynamically change the transceiver data rates, PMA
settings, or protocols of a channel affecting data transfer on adjacent channels.
■
Partial reconfiguration—reconfigure part of the device while other sections of the
device remain operational.
For more information, refer to Increasing Design Functionality with Partial and Dynamic
Reconfiguration in 28-nm FPGAs.
6.

Consider the Altera's recommended coding styles to achieve optimal synthesis results
HDL coding styles can have a significant impact on the quality of results for
programmable logic designs. For example, when designing memory and digital system
processing (DSP) functions, understanding the device architecture helps you to take
advantage of the dedicated logic block sizes and configurations.
7.

■
For specific HDL coding examples and recommendations, refer to the Recommended
HDL Coding Styles chapter in the Quartus II Handbook.
■
You can use the HDL templates provided in the Quartus II software as examples for
your reference. To access the templates, right click the editing area in the Quartus II
text editor and click Insert Template.
■
For additional tool-specific guidelines, refer to the documentation of your synthesis
tool.
Enable the chip-wide reset to clear all registers if required
Arria V and Cyclone V devices support an optional chip-wide reset that enables you to
override all clears on all device registers, including the registers of the memory blocks
(but not the memory contents).
■
DEV_CLRn pin is driven low—all registers are cleared or reset to 0. The affected
register behave as if they are preset to a high value when synthesis performs an
optimization called NOT-gate-push back due to register control signals.
■
DEV_CLRn pin is driven high—all registers behave as programmed.
To enable chip-wide reset, before compiling your design, turn on Enable device-wide
reset (DEV_CLRn) under the Options list of the General category in the Device and Pin
Options dialog box of the Quartus II software.
8.

Use device architecture-specific register control signals
Each Arria V and Cyclone V logic array block (LAB) contains dedicated logic for driving
register control signals to its ALMs. It is important that the control signals use the
dedicated control signals in the device architecture. In some cases, you may be required
to limit the number of different control signals in your design.
For more information about LAB and ALM architecture, refer to the following
documents:
January 2013
Altera Corporation
■
Logic Array Blocks and Adaptive Logic Modules in Arria V Devices
■
Logic Array Blocks and Adaptive Logic Modules in Cyclone V Devices
Arria V and Cyclone V Design Guidelines
Page 32
Design Entry
Table 12. Design Entry Checklist (Part 4 of 6)
No. v Checklist items
9.

Review recommended reset architecture
■
If the clock signal is not available when reset is asserted, an asynchronous reset is
typically used to reset the logic.
■
The recommended reset architecture allows the reset signal to be asserted
asynchronously and deasserted synchronously.
■
The source of the reset signal is connected to the asynchronous port of the registers,
which can be directly connected to global routing resources.
■
The synchronous deassertion allows all state machines and registers to start at the
same time.
■
Synchronous deassertion avoids an asynchronous reset signal from being released
at, or near, the active clock edge of a flipflop that can cause the output of the flipflop
to go to a metastable unknown state.
For more information about good reset design, refer to industry papers such as the
analysis of reset architecture at www.sunburst-design.com/papers.
10.

Review the synthesis options available in your synthesis tool
If you force a particular power-up condition for your design, use the synthesis options
available in your synthesis tool:
■
By default, the Quartus II software Integrated Synthesis turns on the Power-Up Don’t
Care logic option that assumes your design does not depend on the power-up state
of the device architecture. Other synthesis tools might use similar assumptions.
■
Designers typically use an explicit reset signal for the design that forces all registers
into their appropriate values after reset but not necessarily at power-up. You can
create your design with asynchronous reset that allows you to power up the design
safely with the reset active, regardless of the power-up conditions of the device.
■
Some synthesis tools can also read the default or initial values for registered signals
in your source code and implement the behavior in the device. For example, the
Quartus II software Integrated Synthesis converts HDL default and initial values for
registered signals into Power-Up Level settings. The synthesized behavior matches
the power-up conditions of the HDL code during a functional simulation.
■
Registers in the device core always power up to a low (0) logic level in the physical
device architecture. If you specify a high power-up level or a non-zero reset value
(preset signal), synthesis tools typically use the clear signals available on the
registers and perform the NOT-gate push back optimization technique. If you assign a
high power-up level to a register that is reset low, or assign a low power-up value to a
register that is preset high, synthesis tools cannot use the NOT-gate push back
optimization technique and might ignore the power-up conditions.
For more information about the Power-Up Level settings and the altera_attribute
assignment that sets the power-up state, refer to the Quartus II Integrated Synthesis
chapter of the Quartus II Handbook.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Design Entry
Page 33
Table 12. Design Entry Checklist (Part 5 of 6)
No. v Checklist items
11.

Consider resources available for register power-up and control signals
To implement a reset and preset signal on the same register, synthesis tools emulate the
controls with logic and latches that can be prone to glitches because of the different
delays between the different paths to the register. In addition, the power-up value is
undefined for these registers.
For more information about reset logic and power up conditions, refer to the
Recommended HDL Coding Styles chapter in the Quartus II Handbook.
12.

Consider Altera's recommendations for creating design partitions
Partitioning a design for an FPGA requires planning to ensure optimal results when the
partitions are integrated and ensures that each partition is well placed, relative to other
partitions in the device.
Follow Altera's recommendations for creating design partitions to improve the overall
quality of results. For example, registering partition I/O boundaries keeps critical timing
paths inside one partition that can be optimized independently. Plan your source code so
that each design block is defined in a separate file. The software can automatically detect
changes to each block separately.
Use hierarchy in your design to provide more flexibility when partitioning. Keep your
design logic in the leaves of the hierarchy trees; that is, the top level of the hierarchy
should have very little logic, and the lower-level design blocks contain the logic.
For guidelines to help you create design partitions, refer to the Best Practices for
Incremental Compilation Partitions and Floorplan Assignments chapter in the Quartus II
Handbook.
13.

Perform timing budgeting and resource balancing between partitions
If your design is created in multiple projects, it is important that the system architect
provide guidance to designers of lower-level blocks to ensure that each partition uses
the appropriate device resources:
January 2013
Altera Corporation
■
Because the designs are developed independently, each lower-level designer has no
information about the overall design or how their partition connects with other
partitions, which can lead to problems during system integration.
■
The top-level project information, including pin locations, physical constraints, and
timing requirements, should be communicated to the designers of lower-level
partitions before they start their design.
■
The system architect can plan design partitions at the top level and use the Quartus II
software Generate Bottom-Up Design Partition Scripts option on the Project menu
to automate the process of transferring top-level project information to lower-level
modules.
Arria V and Cyclone V Design Guidelines
Page 34
Design Entry
Table 12. Design Entry Checklist (Part 6 of 6)
No. v Checklist items
14.

Create a design floorplan for incremental compilation partitions
■
A design floorplan avoids conflicts between design partitions and ensure that each
partition is well-placed relative to other partitions. When you create different location
assignments for each partition, no location conflicts occur.
■
A design floorplan helps avoid situations in which the Fitter is directed to place or
replace a portion of the design in an area of the device where most resources have
already been claimed.
■
Floorplan assignments are recommended for timing-critical partitions in top-down
flows. You can use the Quartus II Chip Planner to create a design floorplan using
LogicLock region assignments for each design partition.
■
With a basic design framework for the top-level design, the floorplan editor enables
you to view connections between regions, estimate physical timing delays on the
chip, and move regions around the device floorplan.
■
After you compiled the full design, you can also view logic placement and locate
areas of routing congestion to improve the floorplan assignments.
For more information and guidelines in creating a design floorplan and placement
assignments in the floorplan, refer to the following chapters in the Quartus II Handbook:
Arria V and Cyclone V Design Guidelines
■
Best Practices for Incremental Compilation Partitions and Floorplan Assignments
■
Analyzing and Optimizing the Design Floorplan with the Chip Planner
January 2013
Altera Corporation
Design Implementation
Page 35
Design Implementation
Use the checklists in the this section as guidelines while implementing your design.
Synthesis and Compilation
Table 13. Synthesis and Compilation Checklist (Part 1 of 3)
No. v Checklist items
1.

Specify your synthesis tool and use correct supported version
The Quartus II software includes integrated synthesis that fully supports Verilog HDL,
VHDL, Altera hardware description language (AHDL), and schematic design entry. You
can also use industry-leading third-party EDA synthesis tools to synthesize your Verilog
HDL or VHDL design, and then compile the resulting output netlist file in the Quartus II
software:
■
Specify a third-party synthesis tool in the New Project Wizard or the EDA Tools
Settings page of the Settings dialog box to use the correct Library Mapping File
(.lmf) for your synthesis netlist.
■
Altera recommends that you use the most recent version of third-party synthesis
tools because tool vendors are continuously adding new features, fixing tool issues,
and enhancing performance for Altera devices.
■
Different synthesis tools can give different results. If you want to select the
best-performing tool for your application, you can experiment by synthesizing typical
designs for your application and coding style, and comparing the results.
■
Perform placement and routing in the Quartus II software to get accurate timing
analysis and logic utilization results.
■
Your synthesis tool may offer the capability to create a Quartus II project and pass
constraints such as the EDA tool setting, device selection, and timing requirements
that you specified in your synthesis project. You can use this capability to save time
when setting up your Quartus II project for placement and routing.
For more information about supported synthesis tools, refer to the following chapters of
the Quartus II Handbook:
■
Quartus II Integrated Synthesis
■
Synopsys Synplify Support
■
Mentor Graphics Precision Synthesis Support
■
Mentor Graphics LeonardoSpectrum Support
For information about the officially supported version of each synthesis tool in a
Quartus II software version, refer to the relevant Quartus II software release notes on the
Release Notes page at the Altera website.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 36
Design Implementation
Table 13. Synthesis and Compilation Checklist (Part 2 of 3)
No. v Checklist items
2.

Review resource utilization reports after compilation
After compilation in the Quartus II software, review the device resource utilization
information:
■
Use the information to determine whether the future addition of extra logic or other
design changes introduce fitting difficulties.
■
If your compilation results in a no-fit error, use the information to analyze fitting
problems.
■
To determine resource usage, refer to the Flow Summary section of the Compilation
Report for a percentage representing the total logic utilization, which includes an
estimation of resources that cannot be used due to existing connections or logic
usage.
■
For more detailed resource information, view the reports under Resource Section in
the Fitter section of the Compilation Report. The Fitter Resource Usage Summary
report breaks down the logic utilization information and indicates the number of fully
and partially used ALMs, and provides other resource information including the
number of bits in each type of memory block.
There are also reports that describe some of the optimizations that occurred during
compilation. For example, if you use the Quartus II Integrated Synthesis, the reports
under the Optimization Results folder in the Analysis & Synthesis section provide
information that includes registers that were removed during synthesis. Use this report
to estimate device resource utilization for a partial design to ensure that registers were
not removed due to missing connections with other parts of the design.
Low logic utilization does not mean the lowest possible ALM utilization. A design that is
reported to be close to 100% may still have space for extra logic. The Fitter uses ALUTs
in different ALMs, even when the logic can be placed within one ALM, so that it can
achieve the best timing and routability results. Logic might be spread throughout the
device when achieving these results. As the device fills up, the Fitter automatically
searches for logic that can be placed together in one ALM.
3.

Review all Quartus II messages, especially warning or error messages
Each stage of the compilation flow generates messages, including informational notes,
warnings, and critical warnings. Understand the significance of warning messages and
make changes to the design or settings if required.
In the Quartus II user interface, you can use the Message window tabs to look at only
certain types of messages. You can suppress the messages if you have determined that
your action is not required.
For more information about messages and message suppression, refer to the Managing
Quartus II Projects chapter in the Quartus II Handbook.
4.

Consider using incremental compilation
Use the incremental compilation feature to preserve logic in unchanged parts of your
design, preserve timing performance, and reach timing closure more efficiently. You can
speed up design iteration time by an average of 60% when making changes to the
design with the incremental compilation feature.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Design Implementation
Page 37
Table 13. Synthesis and Compilation Checklist (Part 3 of 3)
No. v Checklist items
5.

Ensure parallel compilation is enabled
The Quartus II software can run some algorithms in parallel to take advantage of
multiple processors and reduce compilation time when more than one processor is
available to compile the design. Set the Parallel compilation option on the Compilation
Process Settings page of the Settings dialog box, or change the default setting in the
Options dialog box in the Processing page from the Tools menu.
6.

Use the Compilation Time Advisor
The Compilation Time Advisor provides guidance in making settings that reduce your
design compilation time. On the Tools menu, point to Advisors and click Compilation
Time Advisor. Using some of these techniques to reduce compilation time can reduce
the overall quality of results.
For more information, refer to the Area and Timing Optimization chapter in the
Quartus II Handbook.
Timing Optimization and Analysis
Use the guidelines in the following checklist for analyzing your design timing and
optimizing your timing performance.
Table 14. Timing Optimization and Analysis Checklist (Part 1 of 2)
No. v Checklist items
1.

Ensure timing constraints are complete and accurate
In an FPGA design flow, accurate timing constraints allow timing-driven synthesis
software and place-and-route software to obtain optimal results. Timing constraints are
critical to ensure designs meet their timing requirements, which represent actual design
requirements that must be met for the device to operate correctly.
The Quartus II software optimizes and analyzes your design using different timing
models for each device speed grade, so you must perform timing analysis for the
correct speed grade. The final programmed device might not operate as expected if the
timing paths are not fully constrained, analyzed, and verified to meet requirements.
For more information, refer to the Timing Analysis Overview chapter of the Quartus II
Handbook.
2.

Review the TimeQuest Timing Analyzer reports after compilation
The Quartus II software includes the Quartus II TimeQuest Timing Analyzer, a powerful
ASIC-style timing analysis tool that validates the timing performance of all logic in your
design. It supports the industry standard Synopsys Design Constraints (SDC) format
timing constraints, and has an easy-to-use GUI with interactive timing reports. It is ideal
for constraining high-speed source-synchronous interfaces and clock multiplexing
design structures.
The software also supports static timing analysis in the industry-standard Synopsys
Primetime software. To generate the required timing netlist, specify the tool in the New
Project Wizard or the EDA Tools Settings page of the Settings dialog box.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 38
Design Implementation
Table 14. Timing Optimization and Analysis Checklist (Part 2 of 2)
No. v Checklist items
3.

Ensure that the I/O timings are not violated when data is provided to the FPGA
A comprehensive static timing analysis includes analysis of register to register, I/O, and
asynchronous reset paths. It is important to specify the frequencies and relationships
for all clocks in your design.
Use input and output delay constraints to specify external device or board timing
parameters. Specify accurate timing requirements for external interfacing components
to reflect the exact system intent.
The TimeQuest Timing Analyzer performs static timing analysis on the entire system,
using data required times, data arrival times, and clock arrival times to verify circuit
performance and detect possible timing violations. It determines the timing
relationships that must be met for the design to correctly function. You can use the
report_datasheet command to generate a datasheet report that summarizes the I/O
timing characteristics of the entire design.
4.

Perform Early Timing Estimation before running a full compilation
If the timing analysis reports that your design requirements were not met, you must
make changes to your design or settings and recompile the design to achieve timing
closure. If your compilation results in no-fit messages, you must make changes to get
successful placement and routing.
You can use the Early Timing Estimation feature in the Quartus II software to estimate
your design’s timing results before the software performs full placement and routing. On
the Processing menu, point to Start and click Start Early Timing Estimate to generate
initial compilation results after you have run analysis and synthesis.
5.

Consider the following recommendations for timing optimization and analysis
assignment:
■
Turn on Optimize multi-corner timing on the Fitter Settings page in the Settings
dialog box.
■
Use create_clock and create_generated_clock to specify the frequencies and
relationships for all clocks in your design.
■
Use set_input_delay and set_output_delay to specify the external device or
board timing parameters
■
Use derive_pll_clocks to create generated clocks for all PLL outputs, according
to the settings in the PLL megafunctions. Specify multicycle relationships for LVDS
transmitters or receiver deserialization factors.
■
Use derive_clock_uncertainty to automatically apply inter-clock, intra-clock,
and I/O interface uncertainties.
■
Use check_timing to generate a report on any problem with the design or applied
constraints, including missing constraints
■
Use the Quartus II optimization features to achieve timing closure or improve the
resource utilization.
■
Use the Timing and Area Optimization Advisors to suggest optimization settings.
For more guidelines about timing constraints, refer to The Quartus II TimeQuest Timing
Analyzer chapter in the Quartus II Handbook.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Design Implementation
Page 39
Functional and Timing Simulation
Use the following checklist for guidelines about functional and timing simulation.
Table 15. Functional and Timing Simulation Checklist
No. v Checklist items
1.

Perform functional simulation at the beginning of your design flow
Perform the simulation to check the design functionality or logical behavior of each
design block. You do not have to fully compile your design; you can generate a
functional simulation netlist that does not contain timing information.
2.

Perform timing simulation to ensure your design works in targeted device
Timing simulation uses the timing netlist generated by the TimeQuest Timing Analyzer,
which includes the delay of different device blocks and placement and routing
information. You can perform timing simulation for the top-level design at the end of
your design flow to ensure that your design works in the targeted device.
3.

Specify your simulation tool and use correct supported version
■
Altera provides the ModelSim®-Altera simulator Starter Edition and offers the
higher-performance ModelSim-Altera Edition that enable you to take advantage of
advanced testbench capabilities and other features.
■
In addition, the Quartus II EDA Netlist Writer can generate timing netlist files to
support other third-party simulation tools such as Synopsys VCS, Cadence NC-Sim,
and Aldec Active-HDL.
■
If you use a third-party simulation tool, use the software version that is supported
with your Quartus II software version.
■
Specify your simulation tool in the EDA Tools Settings page of the Settings dialog
box to generate the appropriate output simulation netlist. The software can also
generate scripts to help you setup libraries in your tool with NativeLink integration.
■
Use only the model libraries provided with your Quartus II software version. Libraries
may change between versions and this can cause a mismatch with your simulation
netlist.
■
To create a testbench in the Quartus II software, on the Processing menu, point to
Start and click Start Testbench Template Writer.
For information about the officially supported version of each simulation tool in a
Quartus II software version, refer to the relevant Quartus II software release notes on the
Release Notes page at the Altera website.
For more information, refer to the following documents in the Quartus II Handbook:
January 2013
Altera Corporation
■
Simulating Altera Designs
■
Mentor Graphics ModelSim and QuestaSim Support
■
Synopsys VCS and VCS MX Support
■
Cadence Incisive Enterprise Simulator Support
■
Aldec Active-HDL and Rivera-PRO Support
Arria V and Cyclone V Design Guidelines
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Design Implementation
Formal Verification
Use the following guidelines if your design requires formal verification.
Table 16. Formal Verification Checklist
No. v Checklist items
1.

Determine if you require formal verification for your design
If formal verification is required for your design, it is easier to plan for limitations and
restrictions in the beginning than to make changes later in the design flow.
2.

Check for support and design limitations for formal verification
The Quartus II software supports some formal verification flows. Using a formal
verification flow can impact performance results because it requires that certain logic
optimizations be turned off, such as register retiming, and forces hierarchy blocks to be
preserved, which can restrict optimization.
For more information, refer to the Cadence Encounter Conformal Support chapter in the
Quartus II Handbook.
3.

Specify your formal verification tool and use correct supported version
Specify your formal verification tool in the EDA Tools Settings page of the Settings
dialog box to generate the appropriate output netlist.
For information about the officially supported version of each formal verification tool in a
Quartus II software version, refer to the relevant Quartus II software release notes on the
Release Notes page at the Altera website.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Design Implementation
Page 41
Power Analysis and Optimization
After compiling your design, analyze the power consumption and heat dissipation
with the Quartus II PowerPlay Power Analyzer to calculate the dynamic, static, and
I/O thermal power consumption and ensure the design has not violated power
supply and thermal budgets.
Power optimization in the Quartus II software depends on accurate power analysis
results. Use the following guidelines to ensure the software optimizes the power
utilization correctly for the design’s operating behavior and conditions.
Table 17. Power Analysis and Optimization Checklist (Part 1 of 3)
No. v Checklist items
1.

Provide accurate typical signal activities to get accurate power analysis result
You need to provide accurate typical signal activities to PowerPlay Power Analyzer:
■
Compile a design to derive the information about design resources, placement and
routing, and I/O standards.
■
Derive signal activity data (toggle rates and static probabilities) from simulation
results or a user-defined default toggle rate and vectorless estimation. The signal
activities used for analysis must be representative of the actual operating behavior.
For the most accurate power estimation, use gate-level simulation results with a .vcd
output file from a third-party simulation tool. The simulation activity should include
typical input vectors over a realistic time period and not the corner cases often used
during functional verification. Use the recommended simulator settings, such as glitch
filtering, to ensure good results.
2.

Specify the correct operating conditions for power analysis
Specify the operating conditions, including the core voltage, device power
characteristics, ambient and junction temperature, cooling solution, and the board
thermal model.
In the Quartus II software, select the appropriate settings on the Operating Settings and
Conditions page in the Settings dialog box.
3.

Analyze power consumption and heat dissipation in the PowerPlay Power Analyzer
In the Quartus II software, on the Processing menu, click PowerPlay Power Analyzer
Tool. The tool also provides a summary of the signal activities used for analysis and a
confidence metric that reflects the overall quality of the data sources for signal activities.
For more information about power analysis and recommendations for simulation
settings for creating signal activity information, refer to the PowerPlay Power Analysis
chapter in the Quartus II Handbook.
The PowerPlay Power Analyzer report is a power estimate and is not a power
specification. Always refer to the device datasheet for the power specification.
4.

Review recommended design techniques and Quartus II options to optimize power
consumption
For information about design techniques to optimize power consumption, refer to the
Power Optimization chapter of the Quartus II Handbook.
January 2013
Altera Corporation
Arria V and Cyclone V Design Guidelines
Page 42
Design Implementation
Table 17. Power Analysis and Optimization Checklist (Part 2 of 3)
No. v Checklist items
5.

Use the Power Optimization Advisor to suggest optimization settings
The Power Optimization Advisor provides specific power optimization advice and
recommendations based on the current design project settings and assignments.
For more information, refer to the Power Optimization chapter in the Quartus II
Handbook.
6.

Consider using a faster speed grade device
If your design includes many critical timing paths that require the high-performance
mode, you might be able to reduce power consumption by using a faster speed grade
device if available. With a faster device, the software might be able to set more device
tiles to use the low-power mode.
7.

Optimize the clock power management
Clocks represent a significant portion of dynamic power consumption, because of their
high switching activity and long paths. The Quartus II software automatically optimizes
clock routing power by enabling only the portions of a clock network that are required to
feed downstream registers.
You can also use clock control blocks to dynamically enable or disable the clock
network. When a clock network is powered down, all the logic fed by that clock network
does not toggle, thereby reducing the overall power consumption of the device.
For more information about using clock control blocks, refer to the Clock Control Block
(ALTCLKCTRL) Megafunction User Guide.
To reduce LAB-wide clock power consumption without disabling the entire clock tree,
use the LAB-wide clock enable signal to gate the LAB wide clock. The Quartus II
software automatically promotes register-level clock enable signals to the LAB level.
8.

Reduce the number of memory clocking events
Reduce the number of memory clocking events to reduce memory power consumption.
You can use clock gating or the clock enable signals in the memory ports.
Arria V and Cyclone V Design Guidelines
January 2013
Altera Corporation
Document Revision History
Page 43
Table 17. Power Analysis and Optimization Checklist (Part 3 of 3)
No. v Checklist items
9.
10.


Consider the following I/O power guidelines:
■
The dynamic power consumed in the I/O buffer is proportional to the total load
capacitance—lower capacitance reduces power consumption.
■
Dynamic power is proportional to the square of the voltage. Use lower voltage I/O
standards to reduce dynamic power. Non-terminated I/O standards such as LVTTL
and LVCMOS have a rail-to-rail output swing equal to the VCCIO supply voltage and
consume little static power.
■
Dynamic power is proportional to the output transition frequency. Use
resistively-terminated I/O standards such as SSTL for high-frequency applications.
The output load voltage swings by an amount smaller than the VCCIO around a bias
point. Because of this, the dynamic power is lower than for non-terminated I/O under
similar conditions.
■
Resistively-terminated I/O standards dissipate significant static power because
current is constantly driven into the termination network. Use the lowest drive
strength that meets your speed and waveform requirements to minimize static power
when using resistively terminated I/O standards.
■
The power used by external devices is not included in the PowerPlay Power Analyzer
calculations. Ensure that you include the external devices power separately in your
system power calculations.
Review the information on power-driven compilation and Power Optimization Advisor
For more information, refer to the Power Optimization chapter in the Quartus II
Handbook.
Document Revision History
Table 18 lists the revision history for this document.
Table 18. Document Revision History
Date
Version
January 2013
January 2013
1.0
Altera Corporation
Changes
Initial release.
Arria V and Cyclone V Design Guidelines
Page 44
Arria V and Cyclone V Design Guidelines
Document Revision History
January 2013
Altera Corporation
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