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SanDisk Secure Digital Card
Product Manual
Version 1.9
Document No. 80-13-00169
December 2003
SanDisk Corporation
Corporate Headquarters • 140 Caspian Court • Sunnyvale, CA 94089
Phone (408) 542-0500 • Fax (408) 542-0503
www.sandisk.com
SanDisk® Corporation general policy does not recommend the use of its products in life support applications where in a failure
or malfunction of the product may directly threaten life or injury. Per SanDisk Terms and Conditions of Sale, the user of SanDisk
products in life support applications assumes all risk of such use and indemnifies SanDisk against all damages. See “Limited
Warranty and Disclaimer of Liability.”
This document is for information use only and is subject to change without prior notice. SanDisk Corporation assumes no
responsibility for any errors that may appear in this document, nor for incidental or consequential damages resulting from the
furnishing, performance or use of this material. No part of this document may be reproduced, transmitted, transcribed, stored in
a retrievable manner or translated into any language or computer language, in any form or by any means, electronic,
mechanical, magnetic, optical, chemical, manual or otherwise, without the prior written consent of an officer of SanDisk
Corporation.
SanDisk and the SanDisk logo are registered trademarks of SanDisk Corporation.
Product names mentioned herein are for identification purposes only and may be trademarks and/or registered trademarks of
their respective companies.
© 2003 SanDisk Corporation. All rights reserved.
SanDisk products are covered or licensed under one or more of the following U.S. Patent Nos. 5,070,032; 5,095,344; 5,168,465;
5,172,338; 5,198,380; 5,200,959; 5,268,318; 5,268,870; 5,272,669; 5,418,752; 5,602,987. Other U.S. and foreign patents
awarded and pending.
Lit. No. 80-13-00169 Rev. 1.9 12/2003
Printed in U.S.A.
Revision History
• Revision 1.0 dated 6/2001−initial release.
• Revision 1.1 dated 11/2001−minor editorial and technical changes.
• Revision 1.2 dated 6/2002−minor editorial and technical changes.
• Revision 1.3 dated 7/2002−minor editorial and technical changes.
• Revision 1.4 dated 11/2002—minor editorial change.
• Revision 1.5 dated 3/2003— changed power requirements in Section 2.3, Table 2.3; updated addresses in Appendix A;
adjusted footers and front matter.
• Revision 1.6 dated 8/2003—added 512- and 1024-Mb capacities; updated “Limited Warranty” appendix; added “Disclaimer
of Liability” appendix.
• Revision 1.7 dated 9/2003—minor revisions; added appnote as Appendix A
• Revision 1.8 dated 11/2003—changed VDD read/write values in Section 2 and Table 3-10
• Revision 1.9 dated 12/2003—changed VDD read/write values in Table 3-10
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Table of Contents
1. Introduction to the SD Card ............................................................................................................................... 1-1
1.1. Scope ................................................................................................................................................. 1-2
1.2. Product Models ................................................................................................................................. 1-2
1.3. System Features................................................................................................................................. 1-2
1.4. SD Card Standard.............................................................................................................................. 1-3
1.5. Functional Description ...................................................................................................................... 1-3
1.5.1. Flash Technology Independence............................................................................................. 1-4
1.5.2. Defect and Error Management ................................................................................................ 1-4
1.5.3. Copyright Protection ............................................................................................................... 1-4
1.5.4. Endurance ............................................................................................................................... 1-5
1.5.5. Wear Leveling......................................................................................................................... 1-5
1.5.6. Using the Erase Command...................................................................................................... 1-5
1.5.7. Automatic Sleep Mode............................................................................................................ 1-5
1.5.8. Hot Insertion ........................................................................................................................... 1-5
1.5.9. SD Card—SD Bus Mode ........................................................................................................ 1-6
1.5.9.1. SD Card Standard Compliance .............................................................................. 1-6
1.5.9.2. Negotiating Operation Conditions ......................................................................... 1-6
1.5.9.3. Card Acquisition and Identification....................................................................... 1-6
1.5.9.4. Card Status............................................................................................................. 1-6
1.5.9.5. Memory Array Partitioning.................................................................................... 1-7
1.5.9.6. Read and Write Operations.................................................................................... 1-9
1.5.9.7. Data Transfer Rate ................................................................................................. 1-9
1.5.9.8. Data Protection in the Flash Card .......................................................................... 1-10
1.5.9.9. Erase ...................................................................................................................... 1-10
1.5.9.10. Write Protection................................................................................................... 1-10
1.5.9.11. Copy Bit............................................................................................................... 1-10
1.5.9.12. The CSD Register ................................................................................................ 1-10
1.5.10. SD Card—SPI Mode............................................................................................................. 1-10
1.5.10.1. Negotiating Operating Conditions ....................................................................... 1-11
1.5.10.2. Card Acquisition and Identification..................................................................... 1-11
1.5.10.3. Card Status........................................................................................................... 1-11
1.5.10.4. Memory Array Partitioning.................................................................................. 1-11
1.5.10.5. Read and Write Operations.................................................................................. 1-11
1.5.10.6. Data Transfer Rate ............................................................................................... 1-11
1.5.10.7. Data Protection in the SD Card............................................................................ 1-11
1.5.10.8. Erase .................................................................................................................... 1-11
1.5.10.9. Write Protection................................................................................................... 1-12
1.5.10.10. Copyright Protection.......................................................................................... 1-12
2. Product Specifications ........................................................................................................................................ 2-1
2.1. System Environmental Specifications............................................................................................... 2-1
2.2. Reliability and Durability.................................................................................................................. 2-1
2.3. Typical Card Power Requirements.................................................................................................... 2-2
2.4. System Performance.......................................................................................................................... 2-2
2.5. System Reliability and Maintenance ................................................................................................. 2-2
2.6. Physical Specifications...................................................................................................................... 2-3
3. SD Card Interface Description ........................................................................................................................... 3-1
3.1. General Description of Pins and Registers........................................................................................ 3-1
3.1.1. Pin Assignments in SD Card Mode ........................................................................................ 3-1
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
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3.1.2. Pin Assignments in SPI Mode................................................................................................. 3-2
3.2. SD Bus Topology.............................................................................................................................. 3-3
3.2.1. Power Protection ..................................................................................................................... 3-5
3.3. SPI Bus Topology ............................................................................................................................. 3-5
3.3.1. Power Protection ..................................................................................................................... 3-6
3.4. Electrical Interface ............................................................................................................................ 3-6
3.4.1. Power-up ................................................................................................................................. 3-7
3.4.2. Bus Operating Conditions ....................................................................................................... 3-8
3.4.3. Bus Signal Line Load.............................................................................................................. 3-8
3.4.4. Bus Signal Levels.................................................................................................................... 3-9
3.4.5. Bus Timing.............................................................................................................................. 3-10
3.5. SD Card Registers ............................................................................................................................. 3-11
3.5.1. Operating Conditions Register (OCR) .................................................................................... 3-11
3.5.2. Card Identification (CID) Register.......................................................................................... 3-12
3.5.3. CSD Register........................................................................................................................... 3-13
3.5.4. SCR Register........................................................................................................................... 3-19
3.5.5. Status Register......................................................................................................................... 3-20
3.5.6. SD Status................................................................................................................................. 3-23
3.5.7. RCA Register .......................................................................................................................... 3-23
3.5.8. SD Card Registers in SPI Mode.............................................................................................. 3-24
3.6. Data Interchange Format and Card Sizes .......................................................................................... 3-24
4. Secure Digital (SD) Card Protocol Description.................................................................................................. 4-1
4.1. SD Bus Protocol................................................................................................................................ 4-1
4.2. Protocol’s Functional Description..................................................................................................... 4-4
4.3. Card Identification Mode .................................................................................................................. 4-5
4.3.1. Reset........................................................................................................................................ 4-6
4.3.2. Operating Voltage Range Validation ...................................................................................... 4-7
4.3.3. Card Identification Process ..................................................................................................... 4-7
4.4. Data Transfer Mode .......................................................................................................................... 4-8
4.4.1. Wide Bus Selection/Deselection ............................................................................................. 4-10
4.4.2. Data Read Format ................................................................................................................... 4-10
4.4.3. Data Write Format .................................................................................................................. 4-11
4.4.4. Write Protect Management ..................................................................................................... 4-13
4.4.4.1. Mechanical Write Protect Switch .......................................................................... 4-13
4.4.4.2. Card’s Internal Write Protection (Optional) .......................................................... 4-13
4.4.5. Application Specific Commands............................................................................................. 4-13
4.5. Clock Control .................................................................................................................................... 4-14
4.6. Cyclic Redundancy Codes (CRC)..................................................................................................... 4-15
4.7. Error Conditions................................................................................................................................ 4-17
4.7.1. CRC and Illegal Command ..................................................................................................... 4-17
4.7.2. Read, Write and Erase Time-out Conditions .......................................................................... 4-17
4.8. Commands......................................................................................................................................... 4-17
4.8.1. Command Types ..................................................................................................................... 4-18
4.8.2. Command Format.................................................................................................................... 4-18
4.8.3. Command Classes ................................................................................................................... 4-18
4.8.4. Detailed Command Description .............................................................................................. 4-20
4.9. Card State Transition Table............................................................................................................... 4-24
4.10. Responses........................................................................................................................................ 4-25
4.11. Timings ........................................................................................................................................... 4-27
4.11.1. Command and Response ....................................................................................................... 4-27
4.11.2. Data Read.............................................................................................................................. 4-28
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Table of Contents
4.11.3. Data Write ............................................................................................................................. 4-29
4.11.4. Timing Values....................................................................................................................... 4-32
5. SPI Protocol Definition ...................................................................................................................................... 5-1
5.1. SPI Bus Protocol ............................................................................................................................... 5-1
5.1.1. Mode Selection ....................................................................................................................... 5-1
5.1.2. Bus Transfer Protection .......................................................................................................... 5-2
5.1.3. Data Read................................................................................................................................ 5-2
5.1.4. Data Write ............................................................................................................................... 5-3
5.1.5. Erase and Write Protect Management..................................................................................... 5-4
5.1.6. Read CID/CSD Registers........................................................................................................ 5-4
5.1.7. Reset Sequence ....................................................................................................................... 5-5
5.1.8. Clock Control.......................................................................................................................... 5-5
5.1.9. Error Conditions...................................................................................................................... 5-6
5.1.9.1. CRC and Illegal Commands .................................................................................. 5-6
5.1.9.2. Read, Write and Erase Time-out Conditions ......................................................... 5-6
5.1.10. Memory Array Partitioning................................................................................................... 5-8
5.1.11. Card Lock/Unlock................................................................................................................. 5-8
5.1.12. Application Specific Commands........................................................................................... 5-8
5.1.13. Copyright Protection Commands .......................................................................................... 5-8
5.2. SPI Command Set ............................................................................................................................. 5-8
5.2.1. Command Format.................................................................................................................... 5-8
5.2.2. Command Classes ................................................................................................................... 5-9
5.2.2.1. Detailed Command Description............................................................................. 5-9
5.2.3. Responses................................................................................................................................ 5-12
5.2.3.1. Format R1 .............................................................................................................. 5-13
5.2.3.2. Format R1b ............................................................................................................ 5-13
5.2.3.3. Format R2 .............................................................................................................. 5-13
5.2.3.4. Format R3 .............................................................................................................. 5-14
5.2.3.5. Data Response ....................................................................................................... 5-15
5.2.4. Data Tokens ............................................................................................................................ 5-15
5.2.5. Data Error Token .................................................................................................................... 5-16
5.2.6. Clearing Status Bits................................................................................................................. 5-16
5.3. Card Registers ................................................................................................................................... 5-16
5.4. SPI Bus Timing Diagrams................................................................................................................. 5-16
5.4.1. Command/Response................................................................................................................ 5-17
5.4.2. Data Read................................................................................................................................ 5-18
5.4.3. Data Write ............................................................................................................................... 5-18
5.4.4. Timing Values......................................................................................................................... 5-19
5.5. SPI Electrical Interface...................................................................................................................... 5-19
5.6. SPI Bus Operating Conditions .......................................................................................................... 5-19
5.7. Bus Timing........................................................................................................................................ 5-19
Appendix A. Application Note............................................................................................................................... A-1
Host Design Considerations: NAND MMC and SD-based Products
Introduction .............................................................................................................................................. A-1
Timing ...................................................................................................................................................... A-1
Timing specifications ............................................................................................................................... A-1
Read access and program times................................................................................................................ A-1
Interface.................................................................................................................................................... A-2
Read/Write Mode Selection ..................................................................................................................... A-4
Power and Clock Control ......................................................................................................................... A-4
Initialization Algorithm............................................................................................................................ A-5
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
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File System Support ................................................................................................................................. A-5
Appendix B. Ordering Information ........................................................................................................................ B-1
Appendix C. SanDisk Worldwide Sales Offices .................................................................................................... C-1
Appendix D. Limited Warranty.............................................................................................................................. D-1
Appendix E. Disclaimer of Liability ...................................................................................................................... E-1
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
1. Introduction to the SD Card
The Secure Digital Card is a flash-based memory card that is specifically designed to meet the security, capacity,
performance and environmental requirements inherent in newly emerging audio and video consumer electronic
devices. The SD Card includes a copyright protection mechanism that complies with the security of the SDMI
standard, and is faster and capable of higher Memory capacity. The SD Card security system uses mutual
authentication and a “new cipher algorithm” to protect from illegal usage of the card content. A non-secured access
to the user‘s own content is also available. The physical form factor, pin assignment and data transfer protocol are
forward compatible with the SD Card, with some additions.
The SD Card communication is based on an advanced nine-pin interface (Clock, Command, 4xData and 3xPower
lines) designed to operate in a low voltage range. The communication protocol is defined as part of this
specification. The SD Card host interface supports regular MultiMediaCard operation as well. In other words,
MultiMediaCard forward compatibility was kept. Actually the main difference between SD Card and
MultiMediaCard is the initialization process. The SD Card specifications were originally defined by MEI
(Matsushita Electric Company), Toshiba Corporation and SanDisk Corporation. Currently, the specifications are
controlled by the Secure Digital Association (SDA). The SanDisk SD Card was designed to be compatible with the
SD Card Physical Specification.
The SD Card interface allows for easy integration into any design, regardless of microprocessor used. For
compatibility with existing controllers, the SanDisk SD Card offers, in addition to the SD Card interface, an
alternate communication protocol, which is based on the SPI standard.
The current SD Card provides up to 1024 million bytes of memory using flash memory chips, which were designed
especially for use in mass storage applications. In addition to the mass storage specific flash memory chip, the SD
Card includes an on-card intelligent controller which manages interface protocols, security algorithms for copyright
protection, data storage and retrieval, as well as Error Correction Code (ECC) algorithms, defect handling and
diagnostics, power management and clock control.
SD Bus/SPI Bus
Interface
SanDisk
Single Chip
Controller
Data In/Out
Control
Flash
Modules
SanDisk SD Card
Figure 1-1. SD Card Block Diagram
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
1-1
Introduction to the SD Card
1.1. Scope
This document describes the key features and specifications of the SD Card, as well as the information required to
interface this product to a host system.
1.2. Product Models
The SD Card is available in the capacities shown in Table 1-1.
Table 1-1. SD Card Capacities
Model No.
Capacities
SDSDB-16
16 MB
SDSDB-32
32 MB
SDSDJ-64
64 MB
SDSDJ-128
128 MB
SDSDJ-256
256 MB
SDSDJ-512
512 MB
SDSDJ-1024
1024 MB
SDSDB = Binary NAND technology.
SDSDJ = Multi Level Cell (MLC) NAND technology.
1.3. System Features
The SD Card provides the following features:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
1-2
Up to 1-GB of data storage.
SD Card protocol compatible.
Supports SPI Mode.
Targeted for portable and stationary applications for secured (copyrights protected) and non-secured
data storage.
Voltage range:
−
Basic communication (CMD0, CMD15, CMD55, ACMD41): 2.0—3.6V.
−
Other commands and memory access: 2.7—3.6V.
Variable clock rate 0—25 MHZ.
Up to 12.5 MB/sec data transfer rate (using 4 parallel data lines).
Maximum data rate with up to 10 cards.
Correction of memory field errors.
Copyrights Protection Mechanism—Complies with highest security of SDMI standard.
Password Protected of Cards (not on all models).
Write Protect feature using mechanical switch.
Built-in write protection features (permanent and temporary).
Card Detection (Insertion/Removal).
Application specific commands.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Introduction to the SD Card
•
Comfortable erase mechanism.
The performance of the communication channel is described in Table 1-2.
Table 1-2. SD Bus/SPI Bus Comparison
SD Card Using SD Bus
SD Card Using SPI Bus
Six-wire communication channel (clock, command, 4
data lines).
Three-wire serial data bus (Clock, dataIn, dataOut) + card
specific CS signal (hardwired card selection).
Error-protected data transfer.
Optional non-protected data transfer mode available.
Single or multiple block oriented data transfer.
Single or multiple block oriented data transfer.
1.4. SD Card Standard
SanDisk SD Cards are fully compatible with the following SD Card Physical Layer Specification standard:
The SD Card Physical Layer System Specification, Version 1.01
This specification may be obtained from:
SD Card Association
53 Muckelemi St.
P.O. Box 189
San Juan Bautista, CA 95045-0189
USA
Phone: 831-623-2107
Fax: 831-623-2248
Email: rcreech@sdcard.org
http://www.sdcard.org
1.5. Functional Description
SanDisk SD Cards contain a high level, intelligent subsystem as shown in Figure 1-1. This intelligent
(microprocessor) subsystem provides many capabilities not found in other types of memory cards. These
capabilities include:
•
•
•
•
Host independence from details of erasing and programming flash memory.
Sophisticated system for managing defects (analogous to systems found in magnetic disk drives).
Sophisticated system for error recovery including a powerful error correction code (ECC).
Power management for low power operation.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
1-3
Introduction to the SD Card
1.5.1. Flash Technology Independence
The 512-byte sector size of the SD Card is the same as that in an IDE magnetic disk drive. To write or read a sector
(or multiple sectors), the host computer software simply issues a Read or Write command to the SD Card. This
command contains the address. The host software then waits for the command to complete. The host software does
not get involved in the details of how the flash memory is erased, programmed or read. This is extremely important
as flash devices are expected to get more and more complex in the future. Because the SD Card uses an intelligent
on-board controller, the host system software will not require changing as new flash memory evolves. In other
words, systems that support the SD Card today will be able to access future SanDisk SD Cards built with new flash
technology without having to update or change host software.
1.5.2. Defect and Error Management
SD Cards contain a sophisticated defect and error management system. This system is analogous to the systems
found in magnetic disk drives and in many cases offers enhancements. For instance, disk drives do not typically
perform a read after write to confirm the data is written correctly because of the performance penalty that would be
incurred. SD Cards do a read after write under margin conditions to verify that the data is written correctly. In the
rare case that a bit is found to be defective, SD Cards replace this bad bit with a spare bit within the sector header. If
necessary, SD Cards will even replace the entire sector with a spare sector. This is completely transparent to the
host and does not consume any user data space.
The SD Card’s soft error rate specification is much better than the magnetic disk drive specification. In the
extremely rare case a read error does occur, SD Cards have innovative algorithms to recover the data. This is similar
to using retries on a disk drive but is much more sophisticated. The last line of defense is to employ a powerful ECC
to correct the data. If ECC is used to recover data, defective bits are replaced with spare bits to ensure they do not
cause any future problems. These defect and error management systems coupled with the solid-state construction
give SD Cards unparalleled reliability.
1.5.3. Copyright Protection
A detailed description of the Copyright Protection mechanism and related security SD Card commands can be found
in the SD Card Security Specification document from the SD Card Association. All SD Card security related
commands operate in the data transfer mode.
As defined in the SDMI specification, the data content that is saved in the card is saved already encrypted and it
passes transparently to and from the card. No operation is done on the data and there is no restriction to read the
data at any time. Associated with every data packet (song, for example) that is saved in the unprotected memory
there is a special data that is saved in a protected memory area. For any access (any Read, Write or Erase command)
from/to the data in the protected area. For an authentication procedure is done between the card and the connected
device, either the LCM (PC for example) or the PD (portable device, such as SD player). After the authentication
process passes, the card is ready to accept or give data from/to the connected device. While the card is in the
secured mode of operation (after the authentication succeeded) the argument and the associated data that is sent to
the card or read from the card are encrypted. At the end of the Read, Write or Erase operation, the card gets out
automatically of its secured mode.
1-4
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Introduction to the SD Card
1.5.4. Endurance
SanDisk SD Cards have an endurance specification for each sector of 100,000 writes typical (reading a logical
sector is unlimited). This far exceeds what is typically required in nearly all applications of SD Cards. For example,
even very heavy use of the SD Card in cellular phones, personal communicators, pagers and voice recorders will
use only a fraction of the total endurance over the typical device’s lifetime. For instance, it would take over 10 years
to wear out an area on the SD Card on which a file of any size (from 512 bytes to maximum capacity) was rewritten
3 times per hour, 8 hours a day, 365 days per year.
With typical applications, the endurance limit is not of any practical concern to the vast majority of users.
1.5.5. Wear Leveling
Wear-leveling is an intrinsic part of the Erase Pooling functionality of SD using NAND memory. The SD Card’s
Wear Level command is supported as a NOP operation to maintain backward compatibility with existing software
utilities.
1.5.6. Using the Erase Command
The Erase (sector or group) command provides the capability to substantially increase the write performance of the
SD Card. Once a sector has been erased using the Erase command, a write to that sector will be much faster. This is
because a normal write operation includes a separate sector erase prior to write.
1.5.7. Automatic Sleep Mode
A unique feature of the SanDisk SD Card (and other SanDisk products) is automatic entrance and exit from sleep
mode. Upon completion of an operation, the SD Card will enter the sleep mode to conserve power if no further
commands are received within 5msec. The host does not have to take any action for this to occur. In most systems,
the SD Card is in sleep mode except when the host is accessing it, thus conserving power.
When the host is ready to access the SD Card and it is in sleep mode, any command issued to the SD Card will
cause it to exit sleep and respond.
1.5.8. Hot Insertion
Support for hot insertion will be required on the host but will be supported through the connector. Connector
manufacturers will provide connectors that have power pins long enough to be powered before contact is made with
the other pins. Please see connector data sheets for more details. This approach is similar to that used in PCMCIA
and MMCA devices to allow for hot insertion.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
1-5
Introduction to the SD Card
1.5.9. SD Card—SD Bus Mode
The following sections provide valuable information on the SC Card in SD Bus mode.
1.5.9.1. SD Card Standard Compliance
The SD Card is fully compliant with SD Card Physical Layer Standard Specification V1.01. The structure of the
Card Specific Data (CSD) register is compliant with CSD Structure 1.0.
1.5.9.2. Negotiating Operation Conditions
The SD Card supports the operation condition verification sequence defined in the SD Card standard specifications.
Should the SD Card host define an operating voltage range, which is not supported by the SD Card it will put itself
in an inactive state and ignore any bus communication. The only way to get the card out of the inactive state is by
powering it down and up again.
In Addition the host can explicitly send the card to the inactive state by using the GO_INACTIVE_STATE
command.
1.5.9.3. Card Acquisition and Identification
The SD Card bus is a single master (SD Card host application) and multi-slaves (cards) bus. The Clock and Power
lines are common to all cards on the bus. During the identification process, the host accesses each card separately
through its own command lines. The SD Card’s CID register is pre-programmed with a unique card identification
number, which is used during the identification procedure.
In addition, the SD Card host can read the card’s CID register using the READ_CID SD Card command. The CID
register is programmed during the SD Card testing and formatting procedure, on the manufacturing floor. The SD
Card host can only read this register and not write to it.
An internal pull-up resistor on the DAT3 line may be used for card detection (insertion/removal). The resistor can
be disconnected during data transfer (using ACMD42). Additional practical card detection methods can be found in
SD Physical Specification’s Application Notes given by the SDA.
1.5.9.4. Card Status
The card status is separated into the following two fields:
•
•
1-6
Card Status is stored in a 32-bit status register that is sent as the data field in the card respond to host
commands. Status register provides information about the card’s current state and completion codes
for the last host command. The card status can be explicitly read (polled) with the SEND_STATUS
command.
SD_Status is stored in 512 bits that are sent as a single data block after it was requested by the host
using the SD_STATUS (ACMD13) command. SD_STATUS contains extended status bits that relate
to BUS_WIDTH, security related bits and future specific applications.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Introduction to the SD Card
1.5.9.5. Memory Array Partitioning
The basic unit of data transfer to/from the SD Card is one byte. All data transfer operations which require a block
size always define block lengths as integer multiples of bytes. Some special functions need other partition
granularity. Figure 1-2 shows the Memory Array Partitioning.
For block-oriented commands, the following definition is used:
•
Block—The unit that is related to the block-oriented read and write commands. Its size is the number
of bytes that are transferred when one block command is sent by the host. The size of a block is either
programmable or fixed. The information about allowed block sizes and the programmability is stored
in the CSD.
The granularity of the erasable units is in general not the same as for the block-oriented commands:
•
Sector—The unit that is related to the erase commands. Its size is the number of blocks that are erased
in one portion. The size of a sector is fixed for each device. The information about the sector size (in
blocks) is stored in the CSD.
For devices that include write protection, the following definition is used:
•
WP Group—The minimal unit that may which may have individual write protection. Its size is the
number of groups which will be write protected by one bit. The size of a WP-group is fixed for each
device. The information about the size is stored in the CSD.
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1-7
Introduction to the SD Card
SD Memory Card
WP Group 0
Sector 1
Block
0
Block
1
Block
2
Block
n
Block
2
Block
n
Sector 2
Sector 3
Sector n
WP Group 1
WP Group n
Protected Area (Copyright protection)
Sector 1
Block
0
Block
1
Sector n
Figure 1-2. Memory Array Partitioning
Table 1-3. Memory Array Structures Summary
Part Number
Block Size
(Byte)
Data Area + Protected size
(Blocks)
Protected Area size
(Blocks)
User Area
(Blocks)
SDSDJ-1024
512
2,004,224
20,480
1,983,744
SDSDJ-512
512
1,001,104
10,240
940,864
SDSDJ-256
512
499,456
5,376
494,080
SDSDJ-128
512
248,640
2,624
246,016
SDSDJ-64
512
123,232
1,376
121,856
SDSDB-32
512
60,512
736
59,776
SDSDB-16
512
29,152
352
28,800
NOTE: All measurements are in units per card.
Protected Area—The part of the Card that relates to the secured copyright management and has separate DOS
partitioning including sectors and blocks. The card write protection mechanism does not effect this area.
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Introduction to the SD Card
1.5.9.6. Read and Write Operations
The SD Card supports two read/write modes as shown in Figure 1-3.
Multiple Block Mode
Memory
Sectors
Memory
Sectors
Memory
Sectors
Memory
Sectors
Memory
Sectors
Memory
Sectors
Write
Read
Stop
Start
Address
Memory
Sectors
Start
Address
(Read)
Memory
Sectors
Stop
Start
Single Block Mode
Memory
Sectors
Memory
Sectors
Misalignment Error
Memory
Sectors
Start
Address
(Write)
Memory
Sectors
Memory
Sectors
Memory
Sectors
Start
Address
(Read/Write)
Figure 1-3. Data Transfer Formats
Single Block Mode
In this mode the host reads or writes one data block in a pre-specified length. The data block transmission is
protected with 16-bit CRC that is generated by the sending unit and checked by the receiving unit.
The block length for read operations is limited by the device sector size (512 bytes) but can be as small as a single
byte. Misalignment is not allowed. Every data block must be contained in a single physical sector. The block length
for write operations must be identical to the sector size and the start address aligned to a sector boundary.
Multiple Block Mode
This mode is similar to the single block mode, but the host can read/write multiple data blocks (all have the same
length) which will be stored or retrieved from contiguous memory addresses starting at the address specified in the
command. The operation is terminated with a stop transmission command.
Misalignment and block length restrictions apply to multiple blocks as well and are identical to the single block
read/write operations.
1.5.9.7. Data Transfer Rate
The SD Card can be operated using either a single data line (DAT0) or four data lines (DAT0-DAT3) for data
transfer. The maximum data transfer rate for a single data line is 25 Mbit per second and for four data lines it is 100
Mbit (12 MB) per second.
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1-9
Introduction to the SD Card
1.5.9.8. Data Protection in the Flash Card
Every sector is protected with an Error Correction Code (ECC). The ECC is generated (in the memory card) when
the sectors are written and validated when the data is read. If defects are found, the data is corrected prior to
transmission to the host.
1.5.9.9. Erase
The smallest erasable unit in the SD Card is a sector. In order to speed up the erase procedure, multiple sectors can
be erased at the same time. To facilitate selection, a first command with the starting address is followed by a second
command with the final address, and all sectors within this range will be selected for erase.
1.5.9.10. Write Protection
Two-card level write protection options are available: permanent and temporary. Both can be set using the
PROGRAM_CSD command (see below). The permanent write protect bit, once set, cannot be cleared. This feature
is implemented in the SD Card controller firmware and not with a physical OTP cell.
NOTE: Use the Write Protect (WP) Switch located on the card’s side edge to prevent the host from writing to or
erasing data on the card. The WP switch does not have any influence on the internal Permanent or
Temporary WP bits in the CSD.
1.5.9.11. Copy Bit
The content of a SD Card can be marked as an original or a copy using the copy bit in the CSD register. Once the
Copy bit is set (marked as a copy) it cannot be cleared. The Copy bit of the SD Card is programmed (during test and
formatting on the manufacturing floor) as a copy. The SD Card can be purchased with the copy bit set (copy) or
cleared, indicating the card is a master. This feature is implemented in the SD Card controller firmware and not with
a physical OTP cell.
1.5.9.12. The CSD Register
All the configuration information of the SD Card is stored in the CSD register. The MSB bytes of the register
contain manufacturer data and the two least significant bytes contain the host-controlled data, the card Copy, write
protection and the user file format indication.
The host can read the CSD register and alter the host controlled data bytes using the SEND_CSD and
PROGRAM_CSD commands.
1.5.10. SD Card—SPI Mode
The SPI mode is a secondary communication protocol for SD Cards. This mode is a subset of the SD Card protocol,
designed to communicate with an SPI channel, commonly found in Motorola’s (and lately a few other vendors’)
microcontrollers.
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Introduction to the SD Card
1.5.10.1. Negotiating Operating Conditions
The operating condition negotiation function of the SD Card bus is supported differently in SPI mode by using the
READ_OCR (CMD58) command. The host shall work within the valid voltage range (2.7 to 3.6 volts) of the card
or put the card in inactive state by sending a GO_INACTIVE command to the card.
1.5.10.2. Card Acquisition and Identification
The host must know the number of cards currently connected on the bus. Specific card selection is done via the CS
signal (CD/DAT3). The internal pullup resistor on the CD/DAT3 line may be used for card detection
(insertion/removal). Additional practical card detection methods can be found in SD Physical Specification’s
Application Notes given by the SDA.
1.5.10.3. Card Status
In SPI mode, only 16 bits (containing the errors relevant to SPI mode) can be read out of the 32-bit SD Card status
register. The SD_STATUS can be read using ACMD13, the same as in SD Bus mode.
1.5.10.4. Memory Array Partitioning
Memory partitioning in SPI mode is equivalent to SD Bus mode. All read and write commands are byte addressable
with the limitations given in Section 1.5.9.5.
1.5.10.5. Read and Write Operations
In SPI mode, both single and multiple block data transfer modes are supported.
1.5.10.6. Data Transfer Rate
In the SPI mode, only one data line is used for each direction. The SPI mode data transfer rate is the same as the SD
Bus mode data transfer rate when using one data line only (up to 25 Kbits per second).
1.5.10.7. Data Protection in the SD Card
Same as for the SD Card mode.
1.5.10.8. Erase
Same as in SD Card mode.
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Introduction to the SD Card
1.5.10.9. Write Protection
Same as in SD Card mode.
1.5.10.10. Copyright Protection
Same as in SD Card mode.
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Introduction to the SD Card
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1-13
2. Product Specifications
For all the following specifications, values are defined at ambient temperature and nominal supply voltage unless
otherwise stated.
2.1. System Environmental Specifications
Table 2-1. System Environmental Specifications
Temperature
Operating: -25° C to 85° C
Non-Operating: -40° C to 85° C
Humidity
Operating: 25% to 95%, non-condensing
Non-Operating: 25% to 95%, non-condensing
ESD Protection
Contact Pads: ± 4kV, Human body model according to ANSI
EOS/ESD-S5.1-1998
Non Contact Pad Area: ± 8kV (coupling plane discharge)
± 15kV (air discharge)
Human body model per IEC61000-4-2
2.2. Reliability and Durability
Table 2-2. Reliability and Durability Specifications
Durability
10,000 mating cycles
Bending
10N
Torque
0.15N.m or ±2.5 deg.
Drop Test
1.5m free fall
UV Light Exposure
UV: 254nm, 15Ws/cm2 according to ISO 7816-1
Visual Inspection/Shape and Form
No warpage; no mold skin; complete form; no cavities; surface
smoothness ≤ -0.1 mm/cm2 within contour; no cracks; no
pollution (oil, dust, etc.)
Minimum Moving Force of WP Switch
40 gf (ensures that the WP switch will not slide while it is
inserted in the connector).
WP Switch Cycles
Minimum 1,000 Cycles @ slide force 0.4N to 5N
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2-1
Product Specifications
2.3. Typical Card Power Requirements
Table 2-3. Card Power Requirements
VDD (ripple: max, 60 mV peak to peak)
2.7 V – 3.6 V
(Ta = 25°C @3 V)
Value
Measurement
Notes
Sleep
250
uA
Max
Read
65
mA
Max
Write
75
mA
Max
2.4. System Performance
Table 2-4. System Performance
Typical
Maximum
Block Read Access Time
Binary Products
MLC Products
1.5msec
10msec
100msec
100msec
Block Write Access Time
Binary Products
MLC Products
24msec
40msec
250msec
250msec
CMD1 to Ready
(after power up)
50msec
500msec
Sleep to Ready
1msec
2msec
NOTES: All values quoted are under the following conditions:
1) Voltage range: 2.7 V to 3.6 V.
2) Temperature range: -25° C to 85° C.
3) Are independent of the SD Card clock frequency.
2.5. System Reliability and Maintenance
Table 2-5. System Reliability and Maintenance Specifications
2-2
MTBF
> 1,000,000 hours
Preventive Maintenance
None
Data Reliability
< 1 non-recoverable error in 1014 bits read
Endurance
100,000 write/erase cycles (typical)
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Product Specifications
2.6. Physical Specifications
Refer to Table 2-6 and to Figures 2-1 through 2-3 for SD Card physical specifications and dimensions.
Table 2-6. Physical Specifications
Weight 2.0 g. maximum
Length: 32mm ± 0.1mm
Width: 24mm ± 0.1mm
Thickness: 2.1mm ± 0.15mm
(in substrate area only, 2.25mm maximum)
Figure 2-1. SD Card Dimensions
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
2-3
Product Specifications
Figure 2-2. SD Card Dimensions
2-4
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Product Specifications
Figure 2-3. SD Card Dimensions
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Product Specifications
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
3. SD Card Interface Description
3.1. General Description of Pins and Registers
The SD Card has nine exposed contacts on one side (see Figure 3-1). The host is connected to the SD Card using a
dedicated 9-pin connector.
3.1.1. Pin Assignments in SD Card Mode
Table 3-1 lists the pin assignments and definitions in SD Card Mode.
Table 3-1. SD Bus Mode Pad Definition
Pin #
Name
Type1
SD Description
1
CD/DAT32
I/O3
Card Detect/Data Line [Bit 3]
2
CMD
I/O
Command/Response
3
VSS1
S
Supply voltage ground
4
VDD
S
Supply voltage
5
CLK
I
Clock
6
VSS2
S
Supply voltage ground
7
DAT0
I/O
Data Line [Bit 0]
8
DAT1
I/O
Data Line [Bit 1]
9
DAT2
I/O
Data Line [Bit 2]
NOTES: 1) S=power supply; I=input; O=output using push-pull drivers.
2) The extended DAT lines (DAT1-DAT3) are input on power up. They start to operate as DAT lines after the
SET_BUS_WIDTH command. It is the responsibility of the host designer to connect external pullup resistors to all
data lines even if only DAT0 is to be used. Otherwise, non-expected high current consumption may occur due to the
floating inputs of DAT1 & DAT2 (in case they are not used).
3) After power up, this line is input with 50Kohm(+/-20Kohm) pull-up (can be used for card detection or SPI mode
selection). The pull-up may be disconnected by the user, during regular data transfer, with
SET_CLR_CARD_DETECT (ACMD42) command.
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SD Card Interface Description
3.1.2. Pin Assignments in SPI Mode
Table 3-2 lists the pin assignments and definitions in SPI Mode.
Table 3-2. SPI Bus Mode Pad Definition
Pin #
Name
Type1
SPI Description
1
CS
I
Chip Select (Active low)
2
DataIn
I
Host to Card Commands and Data
3
VSS1
S
Supply Voltage Ground
4
VDD
S
Supply Voltage
5
CLK
I
Clock
6
VSS2
S
Supply Voltage Ground
7
DataOut
O
Card to Host Data and Status
8
RSV(2)
I
Reserved
9
RSV(2)
I
Reserved
NOTES: 1) S=power supply; I=input; O=output.
2) The ‘RSV’ pins are floating inputs. It is the responsibility of the host designer to connect external pullup resistors to
those lines. Otherwise non-expected high current consumption may occur due to the floating inputs.
Each card has a set of information registers (refer to Table 3-3). Detailed descriptions are provided in Section 3.5.
Table 3-3. SD Card Registers
NOTE:
Name
Width
Description
CID
128
Card identification number: individual card number for identification.
RCA1
16
Relative card address: local system address of a card, dynamically
suggested by the card and approved by the host during initialization.
CSD
128
Card specific data: information about the card operation conditions.
SCR
64
SD Configuration Register: information about the SD Card’s special
features capabilities.
OCR
32
Operation Condition Register
1) The RCA register is not available in SPI Mode.
The host may reset the cards by switching the power supply off and on again. The card has its own power-on
detection circuitry which puts the card into an idle state after the power-on. The card can also be reset by sending
the GO_IDLE (CMD0) command.
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SD Card Interface Description
Figure 3-1. SD Card Architecture
3.2. SD Bus Topology
The SD bus has six communication lines and three supply lines:
•
•
•
•
•
CMD—Command is a bi-directional signal. (Host and card drivers are operating in push pull mode.)
DAT0-3—Data lines are bi-directional signals. (Host and card drivers are operating in push pull
mode.)
CLK—Clock is a host to cards signal. (CLK operates in push pull mode.)
VDD—VDD is the power supply line for all cards.
VSS[1:2]—VSS are two ground lines.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
3-3
SD Card Interface Description
Figure 3-2 shows the bus topology of several cards with one host in SD Bus mode.
HOST
CLK
CLK
Vdd
Vss
Vdd
Vss
D0-3(A),
CMD(A)
SD Memory
Card (A)
D0-D3, CMD
CLK
Vdd
Vss
D0-3(B),
CMD(B)
SD Memory
Card (B)
D0-D3, CMD
CLK
Vdd
Vss
D0-3(C)
CMD(C)
D0, CS, CMD
MultiMediaCard
(C)
D1&D2 Not
Connected
Figure 3-2. SD Card System Bus Topology
During the initialization process, commands are sent to each card individually, allowing the application to detect the
cards and assign logical addresses to the physical slots. Data is always sent to each card individually. However, to
simplify the handling of the card stack, after initialization, all commands may be sent concurrently to all cards.
Addressing information is provided in the command packet.
The SD Bus allows dynamic configuration of the number of data lines. After power-up, by default, the SD Card will
use only DAT0 for data transfer. After initialization, the host can change the bus width (number of active data
lines). This feature allows and easy trade off between hardware cost and system performance.
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SD Card Interface Description
R DAT
RCMD
RWP
Write Protect
Vss
CMD
DAT0-3
SD
Memory
CLK
C1 C 2
Card
Host
C3
9
1 2 3 4 5 6 78
SD Memory
Card
Figure 3-3. Bus Circuitry Diagram
RDAT and RCMD are pull-up resistors protecting the CMD and the DAT line against bus floating when no card is
inserted or when all card drivers are in a hi-impedance mode. RWP is used for the Write Protect Switch. See
Section 5.4.2 for the component values and conditions.
Hot Insertion/Removal
Hot insertion and removal are allowed. The SanDisk SD Card will not be damaged by inserting or removing it into
the SD bus even when the power is up:
•
•
The inserted card will be properly reset also when CLK carries a clock frequency fPP.
Data transfer failures induced by removal/insertion should be detected by the bus master using the
CRC codes that suffix every bus transaction.
3.2.1. Power Protection
Cards can be inserted into or removed from the bus without damage. If one of the supply pins (VDD or VSS) is not
connected properly, then the current is drawn through a data line to supply the card.
Data transfer operations are protected by CRC codes; therefore, any bit changes induced by card insertion and
removal can be detected by the SD bus master. The inserted card must be properly reset also when CLK carries a
clock frequency fpp. If the hot insertion feature is implemented in the host, than the host has to withstand a shortcut
between VDD and VSS without damage.
3.3. SPI Bus Topology
The SD Card SPI interface is compatible with SPI hosts available on the market. As any other SPI device the SD
Card SPI channel consists of the following four signals:
•
•
•
•
CS—Host to card Chip Select signal.
CLK—Host to card clock signal.
DataIn—Host to card data signal.
DataOut—Card to host data signal.
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3-5
SD Card Interface Description
Another SPI common characteristic, which is implemented in the SD Card as well, is byte transfers. All data tokens
are multiples of 8-bit bytes and always byte aligned to the CS signal. The SPI standard defines the physical link
only and not the complete data transfer protocol. In SPI Bus mode, the SD Card uses a subset of the SD Card
protocol and command set.
The SD Card identification and addressing algorithms are replaced by a hardware Chip Select (CS) signal. A card
(slave) is selected, for every command, by asserting (active low) the CS signal (see Figure 3-4). The CS signal must
be continuously active for the duration of the SPI transaction (command, response and data). The only exception is
card programming time. At this time the host can de-assert the CS signal without affecting the programming
process.
The bi-directional CMD and DAT lines are replaced by uni-directional dataIn and dataOut signals. This eliminates
the ability of executing commands while data is being read or written. An exception is the multi read/write
operations. The Stop Transmission command can be sent during data read. In the multi block write operation a Stop
Transmission token is sent as the first byte of the data block.
Figure 3-4. SD Card Bus System
3.3.1. Power Protection
Same as for SD Card mode.
3.4. Electrical Interface
The following sections provide valuable information for the electrical interface.
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SD Card Interface Description
3.4.1. Power-up
The power up of the SD Card bus is handled locally in each SD Card and in the bus master.
Logic working level
Supply voltage
VDD max
Valid voltage range
for commands CMD0,
15, 55, and ACMD41
Bus master supply voltage
Valid voltage
range for all
other commands
and memory
access.
V DD min
time
Power up time
Supply ramp up time
Time out value for initialization process = 1 sec
Initialization sequence
Initialization delay:
The maximum of
1 msec, 74 clock cycles
and supply ramp up time
ACMD
41
NCC
ACMD
41
NCC
ACMD
41
NCC
CMD2
Optional repetitions of AMCD41
until no cards are responding
with busy bit set.
Figure 3-5. Power-up Diagram
After power up, including hot insertion ( i.e., inserting a card when the bus is operating) the SD Card enters the idle
state. During this state the SD Card ignores all bus transactions until ACMD41 is received (ACMD command type
shall always precede with CMD55).
ACMD41 is a special synchronization command used to negotiate the operation voltage range and to poll the cards
until they are out of their power-up sequence. Besides the operation voltage profile of the cards, the response to
ACMD41 contains a busy flag, indicating that the card is still working on its power-up procedure and is not ready
for identification. This bit informs the host that the card is not ready. The host has to wait (and continue to poll the
cards, each one on his turn) until this bit is cleared. The maximum period of power up procedure of single card shall
not exceed 1 second.
Getting individual cards, as well as the whole SD Card system, out of idle state is up to the responsibility of the bus
master. Since the power up time and the supply ramp up time depend on application parameters such as the
maximum number of SD Card s, the bus length and the power supply unit, the host must ensure that the power is
built up to the operating level (the same level which will be specified in ACMD41) before ACMD41 is transmitted.
After power up, the host starts the clock and sends the initializing sequence on the CMD line. This sequence is a
contiguous stream of logical ‘1’s. The sequence length is the maximum of 1msec, 74 clocks or the supply-ramp-uptime; the additional 10 clocks (over the 64 clocks after what the card should be ready for communication) is
provided to eliminate power-up synchronization problems.
Every bus master shall have the capability to implement ACMD41 and CMD1. CMD1 will be used to ask
MultiMediaCards to send their Operation Conditions. In any case the ACMD41 or the CMD1 shall be send
separately to each card accessing it through its own CMD line.
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SD Card Interface Description
3.4.2. Bus Operating Conditions
SPI Mode bus operating conditions are identical to SD Card mode bus operating conditions. Table 3-4 lists the
power supply voltages. The CS (chip select) signal timing is identical to the input signal timing (see Figure 3-7).
Table 3-4. Power Supply Voltage
General
Parameter
Symbol
Peak voltage on all lines
Min.
Max.
Unit
-0.3
VDD+0.3
V
10
µA
10
µA
Remark
All Inputs
Input Leakage Current
-10
All Outputs
Output Leakage Current
-10
Power Supply Voltage
Parameter
Symbol
Min.
Max.
Unit
Remark
VDD
2.0
3.6
V
CMD0, 15, 55,
ACMD41 commands
Supply Voltage
2.7
3.6
V
Except CMD0, 15, 55,
ACMD41 commands
Supply voltage differentials (VSS1, VSS2)
-0.3
0.3
V
250
mS
Supply Voltage
Power up Time
From 0V to VDD Min.
3.4.3. Bus Signal Line Load
The total capacitance CL of the CLK line of the SD Card bus is the sum of the bus master capacitance CHOST, the
bus capacitance CBUS itself and the capacitance CCARD of each card connected to this line:
CL = CHOST + CBUS + N∗CCARD
Where N is the number of connected cards. Requiring the sum of the host and bus capacitances not to exceed 30 pF
for up to 10 cards, and 40 pF for up to 30 cards, the values in Table 3-5must not be exceeded.
Table 3-5. Signal Line’s Load
Parameter
Pull-up resistance
Symbol
Min.
Max.
Unit
RCMD
RDAT
10
100
kΩ
To prevent bus floating
Bus signal line capacitance
CL
250
pF
fPP ≤ 5 MHz, 21 cards
Bus signal line capacitance
CL
100
pF
fPP ≤ 20 MHz, 7 cards
CCARD
10
pF
16
nH
fPP ≤ 20 MHz
90
kΩ
May be used for card detection
Single card capacitance
Maximum signal line inductance
Pull-up resistance inside card (pin 1)
3-8
Remark
RDAT3
10
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
SD Card Interface Description
3.4.4. Bus Signal Levels
As the bus can be supplied with a variable supply voltage, all signal levels are related to the supply voltage (see
Figure 3-6).
Figure 3-6. Bus Signal Levels
To meet the requirements of the JEDEC specification JESD8-1A, the card input and output voltages shall be within
the specified ranges in Table 3-6 for any VDD of the allowed voltage range.
Table 3-6. Input and Output Voltages
Parameter
Symbol
Output HIGH voltage
VOH
Output LOW voltage
VOL
Input HIGH voltage
VIH
Input LOW voltage
VIL
Min.
Max.
Unit
Conditions
V
IOH=-100 µA
@VDD (min.)
0.125∗VDD
V
IOL=100 µA
@VDD (min.)
0.625∗VDD
VDD + 0.3
V
VSS-0.3
0.25∗VDD
V
0.75∗VDD
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SD Card Interface Description
3.4.5. Bus Timing
fPP
0.7
tWL
tWH
0.2
Clock
VIH
tTLH
tTHL
tISU
VIL
tIH
VIH
Input
VIL
VOH
Output
VOL
tO DLY
tO DLY (max)
(min)
Shaded areas are not valid.
Figure 3-7. Timing Diagram Data Input/Output Referenced to Clock
Table 3-7. Bus Timing
Parameter
Symbol
Min.
Max.
Unit
Remark
Clock CLK (All values are referred to min. (VIH) and max. (VIL)
3-10
Clock Frequency Data Transfer Mode
fPP
0
25
MHz
CL ≤ 100 pF
(7 cards)
Clock Frequency Identification Mode (The low
frequency is required for MultiMediaCard compatibility)
fOD
0(1)/
100KHz
400
kHz
CL ≤ 250 pF
(21 cards)
Clock Low Time
tWL
10
ns
CL ≤ 100 pF
(7 cards)
Clock High Time
tWH
10
ns
CL ≤ 100 pF
(7 cards)
Clock Rise Time
tTLH
10
ns
CL ≤ 100 pF
(10 cards)
Clock Fall Time
tTHL
10
ns
CL ≤ 100 pF
(7 cards)
Clock Low Time
tWL
50
ns
CL ≤ 250 pF
(21 cards)
Clock High Time
tWH
50
ns
CL ≤ 250 pF
(21 cards)
Clock Rise Time
tTLH
50
ns
CL ≤ 250 pF
(21 cards)
Clock Fall Time
tTHL
50
ns
CL ≤ 250 pF
(21 cards)
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
SD Card Interface Description
Parameter
Symbol
Min.
Max.
Unit
Remark
Inputs CMD, DAT (referenced to CLK)
Input set-up time
tISU
5
ns
CL ≤ 25 pF
(1 cards)
Input hold time
tIH
5
ns
CL ≤ 25 pF
(1 cards)
CL ≤ 25 pF
(1 cards)
Outputs CMD, DAT (referenced to CLK)
NOTE:
Output delay time during Data Transfer Mode
tODLY
0
14
ns
Output delay time during Identification Mode
tODLY
0
50
ns
CL ≤ 25 pF
(1 cards)
OHz stops the clock. The given minimum frequency range is for cases where a continuous clock is required.
3.5. SD Card Registers
There is a set of seven registers within the card interface. The OCR, CID, CSD and SCR registers carry the card
configuration information. The RCA register holds the card relative communication address for the current session.
The card status and SD status registers hold the communication protocol related status of the card.
3.5.1. Operating Conditions Register (OCR)
The 32-bit operation conditions register stores the VDD voltage profile of the card. The SD Card is capable of
executing the voltage recognition procedure (CMD1) with any standard SD Card host using operating voltages form
2 to 3.6 Volts.
Accessing the data in the memory array, however, requires 2.7 to 3.6 Volts. The OCR shows the voltage range in
which the card data can be accessed. The structure of the OCR register is described in Table 3-8.
Table 3-8. OCR Register Definition
OCR Bit
VDD Voltage Window
0-3
Reserved
4
1.6-1.7
5
1.7-1.8
6
1.8-1.9
7
1.9-2.0
8
2.0-2.1
9
2.1-2.2
10
2.2-2.3
11
2.3-2.4
12
2.4-2.5
13
2.5-2.6
14
2.6-2.7
15
2.7-2.8
16
2.8-2.9
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3-11
SD Card Interface Description
OCR Bit
VDD Voltage Window
17
2.9-3.0
18
3.0-3.1
19
3.1-3.2
20
3.2-3.3
21
3.3-3.4
22
3.4-3.5
23
3.5-3.6
24-30
reserved
31
Card power up status bit (busy)
The level coding of the OCR register is as follows:
•
•
Restricted voltage windows=LOW
Card busy=LOW (bit 31)
The least significant 31 bits are constant and will be set as described in Figure 4-8. If bit 32 (the busy bit) is set, it
informs the host that the card power up procedure is finished.
24
00
FF
16
6
8 7
80
4 3
0
0
0
Reserve
Operatin
Voltage
2.7 – 3.6
Reserve
Busy
Figure 3-8. OCR Structure
3.5.2. Card Identification (CID) Register
The CID register is 16 bytes long and contains a unique card identification number as shown in Table 3-9. It is
programmed during card manufacturing and cannot be changed by SD Card hosts. Note that the CID register in the
SD Card has a different structure than the CID register in the MultiMediaCard.
3-12
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SD Card Interface Description
Table 3-9. CID Fields
Name
Type
Width
CID—Slice
Comments
Manufacturer ID (MID)
Binary
8
[127:120]
The manufacturer IDs are controlled
and assigned by the SD Card
Association.
0x03
OEM/Application ID (OID)
ASCII
16
[119:104]
Identifies the card OEM and/or the
card contents. The OID is assigned
by the 3C.*
SD ASCII Code 0x53, 0x44
Product Name (PNM)
ASCII
40
[103:64]
5 ASCII characters long
SD128, SD064, SD032,
SD016, SD008
Product Revision** (PRV)
BCD
8
[63:56]
Two binary coded decimal digits
Product Revision (30)
Serial Number (PSN)
Binary
32
[55:24]
32 Bits unsigned integer
Product Serial Number
4
[23:20]
Reserved
CID Value
Manufacture Date Code (MDT)
BCD
12
[19:8]
Manufacture date–yym (offset from
2000)
Manufacture date(for
example: Apr 2001 = 0x014)
CRC7 checksum*** (CRC)
Binary
7
[7:1]
Calculated
CRC7
Not used, always ‘1’
1
[0:0]
*
3C = The 3 SDA founding companies: Toshiba, SanDisk, and MEI.
**
The product revision is composed of two Binary Coded Decimal (BCD) digits, four bits each, representing an “n.m”
revision number. The “n” is the most significant nibble and the “m” is the least significant nibble. Example: The PRV
binary value filed for product revision “6.2” will be: 0110 0010.
***
The CRC Checksum is computed by the following formula:
CRC Calculation: G(x)=x7+3+1
M(x)=(MID-MSB)*x119+...+(CIN-LSB)*x0
CRC[6...0]=Remainder[(M(x)*x7)/G(x)]
3.5.3. CSD Register
The Card Specific Data (CSD) register contains configuration information required to access the card data. In
Table 3-10, the cell type column defines the CSD field as Read only (R), One Time Programmable (R/W) or
erasable (R/W/E). This table shows the value in “real world” units for each field and coded according to the CSD
structure. The Model dependent column marks (with a check mark, √) the CSD fields that are model dependent.
Note that the CSD register in the SD Card has a different structure than the CSD in the MultiMediaCard.
Table 3-10. CSD Register
Name
Field
Width
Cell
Type
CSD-Slice
CSD Value
CSD Code
CSD structure
CSD_STRUCTURE
2
R
[127:126]
1.0
00b
Reserved
-
6
R
[125:120]
-
000000b
data read access-time-1
TAAC
8
8
R
R
[119:112]
[119:112]
1.5msec
10msec
00100110b
00001111b
data read access-time-2 in CLK cycles NSAC
(NSAC*100)
8
R
[111:104]
0
00000000b
max. data transfer rate
TRAN_SPEED
8
R
[103:96]
25MHz
00110010b
card command classes
CCC
12
R
[95:84]
All (incl. WP,
Lock/unlock)
1F5h
Binary
MLC
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
3-13
SD Card Interface Description
Name
Field
Width
Cell
Type
CSD-Slice
CSD Value
CSD Code
max. read data block length
READ_BL_LEN
4
R
[83:80]
512byte
1001b
partial blocks for read allowed
READ_BL_PARTIAL
1
R
[79:79]
Yes
1b
write block misalignment
WRITE_BLK_MISALIGN
1
R
[78:78]
No
0b
read block misalignment
READ_BLK_MISALIGN
1
R
[77:77]
No
0b
DSR implemented
DSR_IMP
1
R
[76:76]
No
0b
Reserved
-
2
R
[75:74]
-
00b
device size
C_SIZE
12
R
[73:62]
SD128=3843
SD064=3807
SD032=1867
SD016=899
SD008=831
F03h
EDFh
74Bh
383h
33Fh
max. read current @VDD min
VDD_R_CURR_MIN
3
R
[61:59]
100mA
111b
max. read current @VDD max
VDD_R_CURR_MAX
3
R
[58:56]
80mA
110b
max. write current @VDD min
VDD_W_CURR_MIN
3
R
[55:53]
100mA
111b
max. write current @VDD max
VDD_W_CURR_MAX
3
R
[52:50]
80mA
110b
device size multiplier
C_SIZE_MULT
3
R
[49:47]
SD128=64
SD064=32
SD032=32
SD016=32
SD008=16
100b
011b
011b
011b
010b
erase single block enable
ERASE_BLK_EN
1
R
[46:46]
Yes
1b
erase sector size
SECTOR_SIZE
7
R
[45:39]
32blocks
0011111b
write protect group size
WP_GRP_SIZE
7
R
[38:32]
128sectors
1111111b
write protect group enable
WP_GRP_ENABLE
1
R
[31:31]
Yes
1b
Reserved for MultiMediaCard compatibility
2
R
[30:29]
-
00b
write speed factor
Binary
MLC
R2W_FACTOR
R2W_FACTOR
3
3
R
R
[1:16]
[1:4]
X16
X4
100b
010b
max. write data block length
WRITE_BL_LEN
4
R
[25:22]
512Byte
1001b
partial blocks for write allowed
WRITE_BL_PARTIAL
1
R
[21:21]
No
0
Reserved
-
5
R
[20:16]
-
00000b
File format group
FILE_FORMAT_GRP
1
R/W(1) [15:15]
0
0b
copy flag (OTP)
COPY
1
R/W(1) [14:14]
Not Original
1b
permanent write protection
PERM_WRITE_PROTECT
1
R/W(1) [13:13]
Not Protected
0b
temporary write protection
TMP_WRITE_PROTECT
1
R/W
[12:12]
Not Protected
0b
File format
FILE_FORMAT
2
R/W(1) [11:10]
HD w/partition
00b
2
R/W
[9:8]
-
00b
Reserved
CRC
CRC
7
R/W
[7:1]
-
CRC7
not used, always’1’
-
1
-
[0:0]
-
1b
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SD Card Interface Description
NOTE: The device size indicates the user area size. It does not include the protected area that is used for security applications
and is about 1 percent of the total card size.
The following sections describe the CSD fields and the relevant data types. If not explicitly defined otherwise, all
bit strings are interpreted as binary coded numbers starting with the left bit first.
CSD_STRUCTURE—describes the version of the CSD structure.
Table 3-11. CSD Register Structure
CSD_STRUCTURE
0
CSD Structure Version
Valid for SD Card Physical
Specification Version
CSD version No. 1.0
1-3
Version 1.0-1.01
Reserved
TAAC—Defines the asynchronous part (relative to the SD Card clock (CLK)) of the read access time.
Table 3-12. TAAC Access Time Definition
TAAC Bit
Position
Code
2:0
time unit
0=1ns, 1=10ns, 2=100ns, 3=1µms, 4=10µms, 5=100µms, 6=1ms, 7=10ms
6:3
time value
0=reserved, 1=1.0, 2=1.2, 3=1.3, 4=1.5, 5=2.0, 6=2.5, 7=3.0, 8=3.5, 9=4.0,
A=4.5, B=5.0, C=5.5, D=6.0, E=7.0, F=8.0
7
Reserved
NSAC—Defines the worst case for the clock dependent factor of the data access time. The unit for NSAC is 100
clock cycles. Therefore, the maximal value for the clock dependent part of the read access time is 25.5k clock
cycles.
The total read access time NAC as expressed in the Table 5-17 is the sum of TAAC and NSAC. It has to be computed
by the host for the actual clock rate. The read access time should be interpreted as a typical delay for the first data
bit of a data block from the end bit on the read commands.
TRAN_SPEED—Table 3-13 defines the maximum data transfer rate TRAN_SPEED.
Table 3-13. Maximum Data Transfer Rate Definition
TRAN_SPEED Bit
Code
2:0
transfer rate unit
0=100kbit/s, 1=1Mbit/s, 2=10Mbit/s, 3=100Mbit/s, 4... 7=reserved
6:3
time value
0=reserved, 1=1.0, 2=1.2, 3=1.3, 4=1.5, 5=2.0, 6=2.5, 7=3.0,
8=3.5, 9=4.0, A=4.5, B=5.0, C=5.5, D=6.0, E=7.0, F=8.0
7
Reserved
CCC—The SD Card command set is divided into subsets (command classes). The card command class register
CCC defines which command classes are supported by this card. A value of ‘1’ in a CCC bit means that the
corresponding command class is supported. Table 3-14 lists the supported card command classes; refer to Table 4-2
for command class definitions.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
3-15
SD Card Interface Description
Table 3-14. Supported Card Command Classes
CCC Bit
Supported Card Command Class
0
class 0
1
class 1
......
11
class 11
READ_BL_LEN—The maximum read data block length is computed as 2READ_BL_LEN. The maximum block length
might therefore be in the range 512...2048 bytes. Note that in the SD Card, the WRITE_BL_LEN is always equal to
READ_BL_LEN.
Table 3-15. Data Block Length
READ_BL_LEN
Block Length
0-8
9
Reserved
29
= 512 Bytes
......
11
211 = 2048 Bytes
12-15
Reserved
READ_BL_PARTIAL— READ_BL_PARTIAL is always set to 1 in the SD Card. Partial Block Read is always
allowed in the SD Card. It means that smaller blocks can be used as well. The minimum block size is one byte.
READ_BL_PARTIAL=0 means that only the READ_BL_LEN block size can be used for block oriented data
transfers.
READ_BL_PARTIAL=1 means that smaller blocks can be used as well. The minimum block size will be equal to
minimum addressable unit (one byte)
WRITE_BLK_MISALIGN—Defines if the data block to be written by one command can be spread over more
than one physical block of the memory device. The size of the memory block is defined in WRITE_BL_LEN.
WRITE_BLK_MISALIGN=0 signals that crossing physical block boundaries is invalid.
WRITE_BLK_MISALIGN=1 signals that crossing physical block boundaries is allowed.
READ_BLK_MISALIGN—Defines if the data block to be read by one command can be spread over more than
one physical block of the memory device. The size of the memory block is defined in READ_BL_LEN.
READ_BLK_MISALIGN=0 signals that crossing physical block boundaries is invalid.
READ_BLK_MISALIGN=1 signals that crossing physical block boundaries is allowed.
DSR_IMP—Defines if the configurable driver stage is integrated on the card. If set, a driver stage register (DSR)
must be implemented also.
Table 3-16. DSR Implementation Code Table
DSR_IMP
0
3-16
DSR Type
no DSR implemented
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
SD Card Interface Description
1
DSR implemented
C_SIZE (Device Size)—This parameter is used to compute the card capacity (does not include security protected
area). The memory capacity of the card is computed from the entries C_SIZE, C_SIZE_MULT and
READ_BL_LEN as follows:
memory capacity = BLOCKNR * BLOCK_LEN
Where:
BLOCKNR = (C_SIZE+1) * MULT
MULT = 2C_SIZE_MULT+2 (C_SIZE_MULT < 8)
BLOCK_LEN = 2READ_BL_LEN (READ_BL_LEN < 12)
Therefore, the maximum capacity which can be coded is 4096*512*2048 = 4 GBytes. Example: A four MByte card
with BLOCK_LEN = 512 can be coded with C_SIZE_MULT = 0 and C_SIZE = 2047.
VDD_R_CURR_MIN, VDD_W_CURR_MIN—The maximum values for read and write currents at the minimal
VDD power supply are coded in Table 3-17.
Table 3-17. VDD Minimum Current Consumption
VDD_R_CURR_MIN
VDD_W_CURR_MIN
Code For Current Consumption @ VDD
2:0
0=0.5mA; 1=1mA; 2=5mA; 3=10mA; 4=25mA; 5=35mA;
6=60mA; 7=100mA
VDD_R_CURR_MAX, VDD_W_CURR_MAX—The maximum values for read and write currents at the
maximum VDD power supply are coded Table 3-18.
Table 3-18. VDD Maximum Current Consumption
VDD_R_CURR_MAX
VDD_W_CURR_MAX
2:0
Code For Current Consumption @ VDD
0=1mA; 1=5mA; 2=10mA; 3=25mA; 4=35mA;
5=45mA; 6=80mA; 7=200mA
C_SIZE_MULT (Device Size Multiplier)—This parameter is used for coding a factor MULT for computing the
total device size (see ‘C_SIZE’). The factor MULT is defined as 2C_SIZE_MULT+2.
Table 3-19. Multiply Factor For The Device Size
C_SIZE_MULT
MULT
0
22 = 4
1
23 = 8
2
24 = 16
3
25 = 32
4
26 = 64
5
27 = 128
6
28 = 256
7
29 = 512
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3-17
SD Card Interface Description
ERASE_BLK_EN—defines whether erase of one write block (see WRITE_BL_LEN) is allowed (other than
SECTOR_SIZE given below). If ERASE_BLK_EN is 0, the host can erase a unit of SECTOR_SIZE. If
ERASE_BLK_EN is 1, the host can erase either a unit of SECTOR_SIZE or a unit of WRITE_BLK_LEN.
SECTOR_SIZE—The size of an erasable sector. The contents of this register is a 7-bit binary coded value,
defining the number of write blocks (see WRITE_BL_LEN). The actual size is computed by increasing this number
by one. A value of zero means 1 write block, 127 means 128 blocks.
WP_GRP_SIZE—The size of a write protected group. The contents of this register is a 7-bit binary coded value,
defining the number of Erase Groups (see SECTOR_SIZE). The actual size is computed by increasing this number
by one. A value of zero means 1 erase group, 127 means 128 erase groups.
WP_GRP_ENABLE—A value of ‘0’ means no group write protection possible.
R2W_FACTOR—Defines the typical block program time as a multiple of the read access time. Table 3-20 defines
the field format.
Table 3-20. R2W_FACTOR
R2W_FACTOR
Multiples of Read Access Time
0
1
1
2 (write half as fast as read)
2
4
3
8
4
16
5
32
6, 7
Reserved
WRITE_BL_LEN—The maximum write data block length is computed as 2WRITE_BL_LEN. The maximum block
length might therefore be in the range from 512 up to 2048 bytes. A Write Block Length of 512 bytes is always
supported. Note that in the SD Card, the WRITE_BL_LEN is always equal to READ_BL_LEN.
Table 3-21. Data Block Length
WRITE_BL_LEN
0-8
9
Block Length
Reserved
29 = 512 Bytes
….
11
12-15
211 = 2048 Bytes
Reserved
WRITE_BL_PARTIAL—Defines whether partial block sizes can be used in block write commands.
WRITE_BL_PARTIAL=‘0’ means that only the WRITE_BL_LEN block size, and its partial derivatives in
resolution of units of 512 blocks, can be used for block oriented data write.
WRITE_BL_PARTIAL=‘1’ means that smaller blocks can be used as well. The minimum block size is one byte.
FILE_FORMAT_GROUP—Indicates the selected group of file formats. This field is read-only for ROM. The
usage of this field is shown in Table 3-22.
3-18
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SD Card Interface Description
COPY—This bit marks the card as an original (‘0’) or non-original (‘1’). Once set to non-original, this bit cannot
be reset to original. The definition of “original” and “non-original” is application dependent and changes no card
characteristics.
PERM_WRITE_PROTECT—Permanently protects the whole card content, except the secured protected area,
against overwriting or erasing (all write and erase commands for this card are permanently disabled). The default
value is ‘0’, i.e., not permanently write protected.
TMP_WRITE_PROTECT—Temporarily protects the whole card content, except the secured protected area, from
being overwritten or erased (all write and erase commands for this card are temporarily disabled). This bit can be set
and reset. The default value is ‘0’, i.e., not write protected.
FILE_FORMAT—Indicates the file format on the card. This field is read-only for ROM. The following formats
are defined.
Table 3-22. File Format
FILE_FORMAT_GRP FILE_FORMAT
Type
0
0
Hard disk-like file system with partition table
0
1
DOS FAT (floppy-like) with boot sector only (no partition table)
0
2
Universal File Format
0
3
Others/Unknown
1
0, 1, 2, 3
Reserved
CRC—The CRC field carries the check sum for the CSD contents. The checksum has to be recalculated by the host
for any CSD modification. The default corresponds to the initial CSD contents.
3.5.4. SCR Register
In addition to the CSD register, there is another configuration register that is named SD CARD Configuration
Register (SCR). SCR provides information on SD Card's special features that were configured into the given card.
The size of SCR register is 64 bit. This register shall be set in the factory by the SD Card manufacturer. Table 3-23
describes the SCR register content.
Table 3-23. SCR Fields
Description
Field
Width
Cell Type
SCR Slice
SCR Value
SCR Code
SCR Structure
SCR_STRUCTURE
4
R
[63:60]
V1.0
0
SD Card—Spec. Version
SD_SPEC
4
R
[59:56]
V1.01
0
data_status_after erases
DATA_STAT_AFTER_ERASE
1
R
[55:55]
0
0
SD Security Support
SD_SECURITY
3
R
[54:52]
Prot 2, Spec V1.01
2
DAT Bus widths supported
SD_BUS_WIDTHS
4
R
[51:48]
1&4
5
Reserved
-
16
R
[47:32]
0
0
Reserved for manufacturer usage
-
32
R
[31:0]
0
0
SCR_STRUCTURE—Version number of the related SCR structure in the SD Card Physical Layer Specification.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
3-19
SD Card Interface Description
Table 3-24. SCR Register Structure Version
CSD_STRUCTURE
CSD Structure Version
0
SCR version No. 1.0
1-15
Valid for SD Physical Layer
Specification Version
Version 1.0-1.01
reserved
SD_SPEC—Describes the SD Card Physical Layer Specification version supported by this card.
Table 3-25. SD Card Physical Layer Specification Version
SPEC_VERS
0
Physical Layer
Specification Version Number
Version 1.0-1.01
1-15
Reserved
DATA_STAT_AFTER_ERASE—Defines the data status after erase, whether it is ‘0’ or ‘1’ (the status is card
vendor dependent).
SD_SECURITY—Describes the security algorithm supported by the card.
Table 3-26. SD Supported Security Algorithm
SD_SECURITY
Supported Algorithm
0
No security
1
Security protocol 1.0
Security Spec Ver 0.96
2
Security protocol 2.0
Security Spec Ver 1.0-1.01
3 .. 7
Reserved
NOTE: It is mandatory for a Writable SD Card (OTP or R/W) to support Security Protocol.
SD_BUS_WIDTHS—Describes all the DAT bus widths that are supported by this card.
Table 3-27. SD Card Supported Bus Widths
SD_BUS_WIDTHS
Supported Bus Widths
Bit 0
1 bit (DAT0)
Bit 1
Reserved
Bit 2
4 bit (DAT0-3)
Bit 3 [MSB]
Reserved
Since SD Card shall support at least the two bus modes 1bit or 4bit width then any SD Card shall set at least bits 0
and 2 (SD_BUS_WIDTH=0101).
3.5.5. Status Register
The SD Card supports the following two card status fields:
3-20
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
SD Card Interface Description
•
•
Card Status—This status field is compatible to the MultiMediaCard protocol.
SD_Status—This extended status field of 512 bits supports special features unique to the SD Card and
future application specific features.
The SD Card status registers’ structures are defined in Table 3-28. The Type and Clear-Condition fields in the table
are coded as follows:
Type:
•
•
•
•
E—Error bit.
S—Status bit.
R—Detected and set for the actual command response.
X—Detected and set during command execution. The host must poll the card by sending status
command in order to read these bits.
Clear Condition:
•
•
•
A—According to the card current state.
B—Always related to the previous command. Reception of a valid command will clear it (with a delay
of one command).
C—Clear by read.
Table 3-28. Card Status
Bits
Identifier
31
OUT_OF_RANGE
30
Type
Value
Description
Clear
Cond.
ERX
’0’= no error ’1’= error
The command’s argument was out of the allowed
range for this card.
C
ADDRESS_ERROR
ER
’0’= no error ’1’= error
A misaligned address that did not match the
block length was used in the command.
C
29
BLOCK_LEN_ERROR
ER
’0’= no error ’1’= error
The transferred block length is not allowed for
this card, or the number of transferred bytes
does not match the block length.
C
28
ERASE_SEQ_ERROR
ER
’0’= no error ’1’= error
An error in the sequence of erase commands
occurred.
C
27
ERASE_PARAM
ERX
’0’= no error ’1’= error
An invalid selection of write-blocks for erase
occurred.
C
26
WP_VIOLATION
ERX
’0’= not protected ’1’=
protected
Attempt to program a write-protected block.
C
25
CARD_IS_LOCKED
‘0’ = card unlocked
‘1’ = card locked
When set, signals that the card is locked by the
host
A
24
LOCK_UNLOCK_FAIL ED
‘0’ = no error
‘1’ = error
Set when a sequence or password error has
been detected in lock/ unlock card command or if
there was an attempt to access a locked card
C
23
COM_CRC_ERROR
ER
’0’= no error ’1’= error
The CRC check of the previous command failed.
B
22
ILLEGAL_COMMAND
ER
’0’= no error ’1’= error
Command not legal for the card state
B
21
CARD_ECC_FAILED
ERX
’0’= success ’1’= failure
Card internal ECC was applied but failed to
correct the data.
C
20
CC_ERROR
ERX
’0’= no error ’1’= error
Internal card controller error
C
19
ERROR
ERX
’0’= no error
’1’= error
A general or an unknown error occurred during
the operation.
C
SX
ERX
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3-21
SD Card Interface Description
Bits
Identifier
Type
Value
18
Reserved
17
Reserved
16
CID/ CSD_OVERWRITE
ERX
’0’= no error
’1’= error
Description
Can be either one of the following errors:
Clear
Cond.
C
- The CID register has been already written and
can not be overwritten
- The read only section of the CSD does not
match the card content.
- An attempt to reverse the copy (set as original)
or permanent WP (unprotected) bits was made.
15
WP_ERASE_SKIP
SX
’0’= not protected ’1’=
protected
14
CARD_ECC_DISABLE D
SX
’0’= enabled ’1’= disabled The command has been executed without using
the internal ECC.
A
13
ERASE_RESET
SR
’0’= cleared ’1’= set
An erase sequence was cleared before
executing because an out of erase sequence
command was received.
C
CURRENT_STATE
SX
0 = idle
1 = ready
2 = ident
3 = stby
4 = tran
5 = data
6 = rcv
7 = prg
8 = dis
9-15 = reserved
The state of the card when receiving the
command. If the command execution causes a
state change, it will be visible to the host in the
response to the next command.
B
12:9
8
Only partial address space was erased due to
existing write protected blocks.
C
The four bits are interpreted as a binary coded
number between 0 and 15.
READY_FOR_DATA
SX
’0’= not ready
’1’= ready
Corresponds to buffer empty signalling on the
bus.
A
APP_CMD
SR
‘0’ = Disabled
‘1’ = Enabled
The card will expect ACMD, or indication that the
command has been interpreted as ACMD.
C
Error in the sequence of authentication process.
C
7:6
5
4
3
Reserved
AKE_SEQ_ERROR
(SD Card Security spec.)
ER
‘0’ = no error
‘1’ = error
2
Reserved for application specific commands
1, 0
Reserved for manufacturer test mode
3-22
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SD Card Interface Description
3.5.6. SD Status
The SD Status contains status bits that are related to the SD Card proprietary features and may be used for future
application specific usage. The size of the SD Status is one data block of 512 bits. The content of this register is
transmitted to the Host over the DAT bus along with 16 bits CRC. The SD Status is sent to the host over the DAT
bus if ACMD13 is sent (CMD55 followed with CMD13). ACMD13 can be sent to a card only in ‘tran_state’ (card
selected). The SD Status structure is listed in Table 3-29. The same abbreviations for ‘type’ and ‘clear condition’
were used as for the Card Status above.
Table 3-29. SD Card Status
Bits
Identifier
Type
Value
Description
Clear
Cond.
511:
510
DAT_BUS_WIDTH
SR
‘00’=1 (default)
‘01’=reserved
‘10’=4 bit width
‘11’=reserved
Shows the currently defined
data bus width that was
defined by the
SET_BUS_WIDTH command.
A
509
SECURED_MODE
SR
‘0’=not in the mode
‘1’=in secured mode
Card is in Secured Mode of
operation (refer to the SD
Security Specifications
document).
A
In the future, the 8 LSBs will
be used to define different
variations of an SD Card (each
bit will define different SD
types). The 8 MSBs will be
used to define SD Cards that
do not comply with the SD
Memory Card as defined in the
Specification Ver. 1.01
A
Shows the size of the
protected area. The actual
area =
(SIZE_OF_PROTECTED_A
REA) * MULT *
BLOCK_LEN.
A
508:
496
495:
480
Reserved
SD_CARD_TYPE
SR
‘00xxh’=SD Memory Cards
as defined in Physical
Spec. Ver. 1.01
(‘x’=don’t care).
The following cards
are currently defined:
‘0000’=Regular SD
RD/WR Card.
‘0001’=SD ROM Card
479:
448
SIZE_OF_PROTECTED_AREA
447:
312
311:
0
SR
Size of protected area (in
units of
MULT*BLOCK_LEN
refer to CSD register.
Reserved
Reserved for Manufacturer
3.5.7. RCA Register
The 16-bit relative card address register carries the card address that is published by the card during the card
identification. This address is used for the addressed host-card communication after the card identification
procedure.
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3-23
SD Card Interface Description
3.5.8. SD Card Registers in SPI Mode
In SPI mode, all the card’s registers are accessible. Their format is identical to the format in the SD Card mode.
However, a few fields are irrelevant in SPI mode. In SPI mode, the card status register has a different, shorter,
format as well. Refer to the SPI Protocol section for more details.
3.6. Data Interchange Format and Card Sizes
In general, SD Card data is structured by means of a file system. The SD Card File System Specification, published
by the SD Association, describes the file format system that is implemented in the SanDisk SD Card. In general,
each SD Card is divided into two separate DOS-formatted partitions as follows:
•
•
The User Area—used for secured and non-secured data storage and can be accessed by the user with
regular read/write commands.
Security Protected Area—used by copyright protection applications to save security related data and
can be accessed by the host using the secured read/write command after doing authentication as
defined in the SD Security Specification. The security protected area size is defined by SanDisk as
approximately one percent of the total size of the card. Tables 3-30 and 3-31 describe the user and
protected areas for all SanDisk SD Cards.
Table 3-30. Parameters for User Area DOS Image
Capacity
Total
LBAs
No. of Partition
Sys. Area Sectors
Total Partition
Sectors
User Data
Sectors
User Data
Bytes
16 MB
28,800
39
28,743
28,704
14,696,448
32 MB
59,776
45
59,725
59,680
30,556,160
64 MB
121,856
57
121,817
121,760
62,341,120
128 MB
246,016
95
245,919
245,824
125,861,888
256 MB
494,080
155
493,979
493,824
252,837,888
512 MB
990,864
275
990,627
990,352
507,060,224
1024 MB
1,983,744
519
1,983,495
1,982,976
1,015,283,712
Table 3-31. Parameters for Protected Area DOS Image
3-24
Capacity
Total
LBAs
No. of Partition
Sys. Area Sectors
Total Partition
Sectors
User Data
Sectors
User Data
Bytes
16 MB
352
35
351
316
161,792
32 MB
736
37
733
696
356,352
64 MB
1,376
37
1,373
1,336
684,032
128 MB
2,624
35
2,611
2,576
1,318,912
256 MB
5376
37
5365
5328
2,727,936
512 MB
10,240
37
10,213
10,176
5,210,112
1024 MB
20,480
37
20,421
20,384
10,436,608
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SD Card Interface Description
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3-25
4. Secure Digital (SD) Card Protocol Description
4.1. SD Bus Protocol
Communication over the SD bus is based on command and data bit streams, which are initiated by a start bit and
terminated, by a stop bit:
•
•
•
Command—A command is a token that starts an operation. A command is sent from the host either to
a single card (addressed command) or to all connected cards (broadcast command). A command is
transferred serially on the CMD line.
Response—A response is a token that is sent from an addressed card, or (synchronously) from all
connected cards, to the host as an answer to a previously received command. A response is transferred
serially on the CMD line.
Data—Data can be transferred from the card to the host or vice versa. Data is transferred via the data
lines.
From
host to
card
From
host to
card(s)
CMD
Command
From
card to
host
Command
Response
DAT
Operation (no response)
Operation (no data)
Figure 4-1. “No Response” and “No Data” Operations
Card addressing is implemented using a session address that is assigned to the card during the initialization phase.
The basic transaction on the SD bus is the command/response transaction (see Figure 4-1). This type of bus
transaction transfers their information directly within the command or response structure. In addition, some
operations have a data token.
Data transfers to/from the SD Card are done in blocks. Data blocks are always followed by CRC bits. Single and
multiple block operations are defined. Note that the Multiple Block operation mode is better for faster write
operation. A multiple block transmission is terminated when a stop command follows on the CMD line. Data
transfer can be configured by the host to use single or multiple data lines (as long as the card supports this feature).
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
4-1
Secure Digital (SD) Card Protocol Description
From
host to
card(s)
From
card to
host
Command
CMD
Stop command
stops data transfer
Data from
card to host
Command
Response
DAT
Data block
crc
Data block
crc
Data block
Response
crc
Data stop operation
Block read operation
Multiple block read operation
Figure 4-2. Multiple Block Read Operation
The block write operation uses a simple busy signaling of the write operation duration on the DAT0 data line (see
Figure 4-3) regardless of the number of data lines used for transferring the data.
From
host to
card
From
card to
host
Command
CMD
Data
from card
to host
Command
Response
DAT
Stop
command
stops data
transfer
crc OK
response
and busy
from card
Data block
crc
Busy
Data block
crc
Response
Busy
Data stop operation
Block write operation
Multiple block write operation
Figure 4-3. Multiple Block Write Operation
Command tokens have the coding scheme shown in Figure 4-4.
Command content: command and
address information or parameter,
protected by 7 bit CRC checksum
Transmitter bit:
'1'=host command
End bt:
always '1'
Start bit
always '0'
0
1
Content
CRC
1
Total length = 48 bits
Figure 4-4. Command Token Format
Each command token is preceded by a start bit (‘0’) and succeeded by an end bit (‘1’). The total length is 48 bits.
Each token is protected by CRC bits so that transmission errors can be detected and the operation may be repeated.
4-2
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Secure Digital (SD) Card Protocol Description
Response tokens have four coding schemes depending on their content. The token length is either 48 or 136 bits.
The CRC protection algorithm for block data is a 16-bit CCITT polynomial. All used CRC types are described in
Section 4.6.
Transmitter bit:
'0'=card response
Response content: mirrored command and status
information (R1 response), OCR register (R3 response)
or RCA (R6) protected by 7 bit CRC checksum
End bt:
always '1'
Start bit
always '0'
R1, R3, R6
0
0
Content
1
End bt:
always '1'
Total length = 48 bits
R2
0
0
Content = CID or CSD
CRC
1
Total length = 136 bits
Figure 4-5. Response Token Format
In the CMD line, the MSB bit is transmitted first, whereas the LSB bit is transmitted last.
When the wide bus option is used, the data is transferred 4 bits at a time (see Figure 4-6). Start and end bits, as well
as the CRC bits, are transmitted for every one of the DAT lines. CRC bits are calculated and checked for every
DAT line individually. The CRC status response and Busy indication will be sent by the card to the host on DAT0
only (DAT1-DAT3 during that period are “don’t care”).
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4-3
Secure Digital (SD) Card Protocol Description
MSB (4095)
LSB (0)
End bt:
always '1'
Start bit
always '0'
Standard busy
(only DAT0 used):
0
CRC
1
Block length
MSN
LSN
End bt:
always '1'
Start bit
always '0'
Wide bus (all four
data lines used):
DAT3
0
4095
3
CRC
1
DAT2
0
4094
2
CRC
1
DAT1
0
4093
1
CRC
1
DAT0
0
4092
0
CRC
1
Block length /4
Figure 4-6. Data Packet Format
4.2. Protocol’s Functional Description
All communication between the host and SD Cards is controlled by the host (master). The host sends the following
two types of commands:
•
•
Broadcast Commands—Broadcast commands are intended for all SD Cards. Some of these
commands require a response.
Addressed (Point-to-Point) Commands—The addressed commands are sent to the addressed SD
Card and cause a response to be sent from this card.
A general overview of the command flow is shown in Figure 5-7 for the Card Identification Mode and in Figure 5-8
for the Data Transfer Mode. The commands are listed in the command tables (Tables 4-3 through 4-10). The
dependencies between the current SD Card state, received command and following state are listed in Table 4-11. In
the following sections, the different card operation modes will be described first. Thereafter, the restrictions for
controlling the clock signal are defined. All SD Card commands together with the corresponding responses, state
transitions, error conditions and timings are presented in the following sections.
4-4
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
Two operation modes are defined for SD Cards:
•
•
Card Identification Mode—The host will be in card identification mode after reset and while it is
looking for new cards on the bus. SD Cards will be in this mode after reset until the SEND_RCA
command (CMD3) is received.
Data Transfer Mode—SD Cards will enter data transfer mode once their RCA is first published. The
host will enter data transfer mode after identifying all of the SD Cards on the bus.
Table 4-1 lists the dependencies between operation modes and card states. Each state in the SD Card state diagram
(Figures 4-7 and 4-8) is associated with one operation mode.
Table 4-1. Overview of Card States versus Operation Modes
Card State
Inactive State
Operation Mode
Inactive
Idle State
Ready State
Card Identification Mode
Identification State
Stand-by State
Transfer State
Sending-data State
Data Transfer Mode
Receive-data State
Programming State
Disconnect State
4.3. Card Identification Mode
While in Card Identification Mode, the host resets all the cards that are in Card Identification Mode, validates
operation voltage range, identifies cards and asks them to publish Relative Card Address (RCA). This operation is
done to each card separately on its own CMD line. All the data communication in the Card Identification Mode uses
only the command line (CMD).
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4-5
Secure Digital (SD) Card Protocol Description
Power On
SPI Operation
Mode
CMD0
CS Asserted ("0")
Card is Busy
or Host ommitted
voltage range
Idle State
(idle)
CMD0
ACMD41
Inactive State
(ina)
No response
(non-valid command)
Must be an MMC
Start MMC
initialization process
starting at CMD1
Ready State
(ready)
From all states except (ina)
CMD15
Cards with non-compatible
voltage range
CMD2
Identification
State (ident)
Card Identification Mode
Data Transfer Mode
CMD3
Card responds
with new RCA
Stand-by
State (stby)
CMD3
Card responds
with new RCA
From all States in Data
Transfer Mode
Figure 4-7. SD Card State Diagram (Card Identification Mode)
4.3.1. Reset
GO_IDLE_STATE (CMD0) is the software reset command and sets each SD Card to Idle State regardless of the
current card state. SD Cards in Inactive State are not affected by this command.
After power-on by the host, all SD Cards are in Idle State, including the cards that were in Inactive State. Note that
at least 74 clock cycles are required prior to starting bus communication.
After power-on or CMD0, all SD Cards’ CMD lines are in input mode, waiting for the start bit of the next
command. The cards are initialized with a default relative card address (RCA=0x0000) and with a default driver
stage register setting (lowest speed, highest driving current capability).
4-6
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Secure Digital (SD) Card Protocol Description
4.3.2. Operating Voltage Range Validation
The SD Physical Specification standard requires that all SD Cards will be able to establish communication with the
host using any operating voltage between VDD-min and VDD-max. However, during data transfer, minimum and
maximum values for VDD are defined in the operation condition register (OCR) and may not cover the whole range.
SD Card hosts are expected to read the card’s OCR register and select proper VDD values or reject the card.
SD Cards that store the CID and CSD data in the payload memory can communicate this information only under
data-transfer VDD conditions. This means if host and card have non-compatible VDD ranges, the card will not be able
to complete the identification cycle, nor to send CSD data.
SD_SEND_OP_COND (ACMD41) is designed to provide SD Card hosts with a mechanism to identify and reject
cards that do not match the host’s desired VDD range. This is accomplished by the host sending the required VDD
voltage window as the operand of this command. SD Cards that cannot perform data transfer in the specified range
must discard themselves from further bus operations and go into Inactive State. Note that ACMD41 is an
application-specific command. Therefore, APP_CMD (CMD55) will always precede ACMD41. The RCA to be
used for CMD55 in idle_state will be the card’s default RCA = 0x0000.
The MultiMediaCard will not respond to ACMD41 (actually it will not respond to APP_CMD—CMD55, that
precedes it). The MultiMediaCard will be initialized as per the MultiMediaCard spec, using SEND_OP_COND
command (CMD1 of MultiMediaCard). The host should ignore an ILLEGAL_COMMAND status in the
MultiMediaCard response to CMD3, since it is a residue of ACMD41 which is invalid in the MultiMediaCard
(CMD0, 1, 2 do not clear the status register). Actually, ACMD41 and CMD1 will be used by the host to distinguish
between MultiMediaCard and SD Cards in a system.
By omitting the voltage range in the command, the host can query each card and determine if there are any non
compatibilities before sending out-of-range cards into the Inactive State. This query should be used if the host can
select a common voltage range or wants to notify the application of non-usable cards in the stack.
The busy bit in the ACMD41 response can be used by a card to tell the host that it is still working on its powerup/reset procedure (e.g., downloading the register information from memory field) and is not ready yet for
communication. In this case the host must repeat ACMD41 until the busy bit is cleared.
During the initialization procedure, the host is not allowed to change the OCR values. Changes in the OCR content
will be ignored by the SD Card. If there is a real change in the operating conditions, the host must reset the card
stack (using CMD0) and begin the initialization procedure once more. However, for accessing the cards already in
Inactive State, a hard reset must be done by switching the power supply off and on.
GO_INACTIVE_STATE (CMD15) can also be used to send an addressed SD Card into the Inactive State. This
command is used when the host explicitly wants to deactivate a card (e.g., host is changing VDD into a range which
is known to be not supported by this card).
4.3.3. Card Identification Process
The host starts the card identification process with the identification clock rate fOD (see Section 3.4.4). In SD Card
the CMD line output drives are push-pull drivers.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
4-7
Secure Digital (SD) Card Protocol Description
After the bus is activated, the host will request the cards to send their valid operation conditions (ACMD41
preceding with APP_CMD—CMD55 with RCA=0x0000). The response to ACMD41 is the operation condition
register of the card. The same command shall be send to all of the new cards in the system. Incompatible cards are
sent into Inactive State. The host then issues the command ALL_SEND_CID (CMD2) to each card to get its unique
card identification (CID) number. Card that is unidentified (i.e., which is in Ready State) sends its CID number as
the response (on the CMD line). After the CID was sent by the card, it goes into Identification State. Thereafter, the
host issues CMD3 (SEND_RELATIVE_ADDR) asking the card to publish a new relative card address (RCA),
which is shorter than CID and which will be used to address the card in the future data transfer mode (typically with
a higher clock rate than fOD). Once the RCA is received, the card state changes to the Stand-by State. At this point, if
the host wants the card to have another RCA number, it may ask the card to publish a new number by sending
another SEND_RELATIVE_ADDR command to the card. The last published RCA is the actual RCA number of the
card.
The host repeats the identification process (i.e., the cycles with CMD2 and CMD3 for each card in the system).
After all the SD Cards are initialized, the host will initialize the MultiMediaCards that are in the system (if any),
using the CMD2 and CMD3 as given in the MultiMediaCard spec. Note that in the SD system, all the cards are
connected separately so each MultiMediaCard will be initialized individually.
4.4. Data Transfer Mode
Until the content of all CSD registers is known by the host, the fPP clock rate must remain at fOD because some cards
may have operating frequency restrictions. The host issues SEND_CSD (CMD9) to obtain the Card Specific Data
(CSD register), e.g., block length, card storage capacity, maximum clock rate. Figure 4-8 shows a block diagram of
the Data Transfer Mode.
4-8
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
Card Identification
mode
CMD3
CMD15
CMD0
Sending-data
state (data)
Data-transfer
mode
From all states in
data-transfer mode
CMD13, CMD55
CMD12
"operation
complete"
No state transition
in data-transfer mode
CMD17, 18, 30, 56(r)
ACMD51
CMD7
Stand-by state
(stby)
CMD7
CMD4,
9, 10
CMD28,
29, 38
"Operation
complete"
"Operation
complete"
Transfer
state (tran)
CMD 16, 32...37
ACMD6, 13, 42
ACMD 22,23
CMD24, 25, 26,
27, 42, 56(w)
Receive-data
state (rcv)
Disconnect
state (dis)
CMD7
Programming
state (prg)
CMD12 or
"transfer end"
CMD7
Figure 4-8. SD Card State Diagram (Data Transfer Mode)
CMD7 is used to select one SD Card and place it in the Transfer State. Only one SD Card can be in the Transfer
State at a given time. If a previously selected SD Card is in the Transfer State, its connection with the host is
released and it will move back to the Stand-by State. When CMD7 is issued with the reserved relative card address
“0x0000,” all cards transfer back to Stand-by State. (Note that it is the responsibility of the Host to reserve the
RCA=0 for card de-selection—refer to Table 4-3, CMD7 description). This may be used before identifying new
cards without resetting other already registered cards. Cards that already have an RCA do not respond to
identification commands (ACMD41, CMD2, CMD3) in this state.
Important Note: The card de-selection is done if a certain card gets CMD7 with un-matched RCA. That happens
automatically if selection is done to another card and the CMD lines are common. So, in the SD Card system, it will
be the responsibility of the host either:
•
•
To work with the common CMD line (after initialization is done). In this case the card de-selection
will be done automatically (as in MultiMediaCard system).
If the CMD lines are separate, to be aware of the necessity to deselect cards.
All data communication in the Data Transfer Mode is point-to point between the host and the selected SD Card
(using addressed commands). All addressed commands are acknowledged with a response on the CMD line.
The relationship between the various data transfer modes is summarized in Figure 4-8, and in the following
paragraphs:
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
4-9
Secure Digital (SD) Card Protocol Description
•
•
•
•
•
•
•
•
•
•
•
All data read commands may be aborted any time by the stop command (CMD12). The data transfer
will terminate and the card will return to the Transfer State. The read commands are: block read
(CMD17), multiple block read (CMD18), send write protect (CMD30), send scr (ACMD51) and
general command in read mode (CMD56).
All data write commands can be aborted any time by the stop command (CMD12). The write
commands must be stopped prior to deselecting the card by CMD7. The write commands are: block
write (CMD24 and CMD25), write CID (CMD26), write CSD (CMD27), lock/unlock command
(CMD42) and general command in write mode (CMD56).
As soon as the data transfer is completed, the card will exit the data write state and move either to the
Programming State (transfer is successful) or Transfer State (transfer failed).
If a block write operation is stopped and the block length and CRC of the last block are valid, the data
will be programmed.
The card may provide buffering for block write. This means that the next block can be sent to the card
while the previous is being programmed. If all write buffers are full, and as long as the card is in
Programming State (see SD Card state diagram Figure 5-8), the DAT0 line will be kept low (BUSY).
There is no buffering option for write CSD, write CID, write protection and erase. This means that
while the card is busy servicing any one of these commands, no other data transfer commands will be
accepted. DAT0 line will be kept low as long as the card is busy and in the Programming State.
Actually if the CMD and DAT0 lines of the cards are kept separated and the host keeps the busy
DAT0 line disconnected from the other DAT0 lines (of the other cards), the host may access the other
cards while the card is in busy.
Parameter set commands are not allowed while the card is programming. Parameter set commands are:
set block length (CMD16), erase block start (CMD32) and erase block end (CMD33).
Read commands are not allowed while the card is programming.
Moving another card from Stand-by to Transfer State (using CMD7) will not terminate erase and
programming operations. The card will switch to the Disconnect State and will release the DAT line.
A card can be reselected while in the Disconnect State, using CMD7. In this case the card will move to
the Programming State and reactivate the busy indication.
Resetting a card (using CMD0 or CMD15) will terminate any pending or active programming
operation. This may destroy the data contents on the card. It is the host’s responsibility to prevent this.
4.4.1. Wide Bus Selection/Deselection
Wide Bus (4 bit bus width) operation mode may be selected/deselected using ACMD6. The default bus width after
power up or GO_IDLE (CMD0) is 1 bit bus width. ACMD6 command is valid in ‘tran state‘ only. That means that
the bus width may be changed only after a card was selected (CMD7).
4.4.2. Data Read Format
The DAT bus line is high when no data is transmitted. A transmitted data block consists of a start bit (LOW),
followed by a continuous data stream. The data stream contains the net payload data (and error correction bits if an
off-card ECC is used). The data stream ends with an end bit (HIGH). The data transmission is synchronous to the
clock signal.
The payload for block-oriented data transfer is preserved by a CRC check sum. The generator polynomial is a
standard CCITT polynomial:
x16+x12+x5+1
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Secure Digital (SD) Card Protocol Description
The code is a shortened BCH code with d=4 and is used for payload length of up to 2048 Bytes. Note that the CRC
check sum is calculated and attached to each DAT line at the end of the block. In the case of a wide bus operation
(DAT0-DAT3), the 16-bit CRC is calculated separately for each DAT line.
Block Read
A block read is a block-oriented data transfer. The basic unit of data transfer is a block whose maximum size is
defined in the CSD (READ_BL_LEN). Smaller blocks whose starting and ending address are wholly contained
within one physical block (as defined by READ_BL_LEN) may also be transmitted. A CRC is appended to the end
of each block ensuring data transfer integrity. CMD17 (READ_SINGLE_BLOCK) starts a block read, and after a
complete transfer the card goes back to Transfer State. CMD18 (READ_MULTIPLE_BLOCK) starts a transfer of
several consecutive blocks. Blocks will be continuously transferred until a stop command is issued. The stop
command has an execution delay due to the serial command transmission. The data transfer stops after the end bit of
the stop command.
If the host uses partial blocks whose accumulated length is not block aligned, the card will, at the beginning of the
first misaligned block, detect a block misalignment error, set the ADDRESS_ERROR error bit in the status register,
abort transmission and wait (in the Data State) for a stop command.
4.4.3. Data Write Format
The data transfer format is similar to the data read format. For block-oriented write data transfer, the CRC check bits
are added to each data block. The card performs a CRC check for each data line at the end of each received data
block prior to a write operation. (The polynomial is the same one used for a read operation.) With this mechanism,
writing of erroneously transferred data can be prevented.
Block Write
During block write (CMD24—27,42,56(w)), one or more blocks of data are transferred from the host to the card,
with CRC appended to the end of each block by the host. The SanDisk SD Card is able to accept a block of data
defined by WRITE_BL_LEN of 512 bytes. If the CRC fails, the card shall indicate the failure on the DAT line (see
below); the transferred data will be discarded and not written, and all further transmitted blocks (in multiple block
write mode) will be ignored.
Multiple block write command shall be used rather than continuous single write commands to make faster write
operation. Partial block writes (blocks smaller than 512 bytes) are not allowed in the SanDisk SD Card.
The write operation will be aborted if the host tries to write over a write-protected area. In this case, the card sets the
WP_VIOLATION bit in the status register, and while ignoring all further data transfer, waits in the Receive-dataState for a stop command.
Programming of the CID and CSD registers does not require a previous block length setting. The transferred data is
also CRC protected. If a part of the CSD or CID register is stored in ROM, then this unchangeable part must match
the corresponding part of the receive buffer. If this match fails, then the card will report an error and not change any
register contents.
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Secure Digital (SD) Card Protocol Description
After receiving a block of data and completing the CRC check, the card will begin writing and hold the DAT0 line
low if its write buffer is full and unable to accept new data from a new WRITE_BLOCK command. The host may
poll the status of the card with a SEND_STATUS command (CMD13) at any time, and the card will respond with
its status. The status bit READY_FOR_DATA indicates whether the card can accept new data or whether the write
process is still in progress. The host may deselect the card by issuing CMD7 (to select a different card), which will
displace the card into the Disconnect State and release the DAT line without interrupting the write operation. When
reselecting the card, it will reactivate busy indication by pulling DAT to low if programming is still in progress and
the write buffer is unavailable. Actually, the host may perform simultaneous write operations to several cards by
using an inter- leaving process. The interleaving process can be done by accessing each card separately while other
cards are in busy. This process can be done by proper CMD and DAT0-3 line manipulations (disconnection of busy
cards).
Pre-erase setting prior to a multiple block write operation
Setting a number of write blocks to be pre_erased (ACMD23) will make a following Multiple Block Write
operation faster compared to the same operation without preceding ACMD23. The host will use this command to
define how many write blocks are going to be sent in the next write operation. If the host terminates the write
operation (using stop transmission) before all the data blocks are sent to the card, the content of the remaining write
blocks is undefined (can be either erased or still have the old data). If the host sends a greater number of write
blocks than are defined in ACMD23, the card will erase blocks one by one (as new data is received). This number
will be reset to the default (=1) value after Multiple Blocks Write operation.
It is recommended to use this command preceding CMD25, so that SanDisk’s SD Card will be faster for Multiple
Write Blocks operation. Note that the host must send ACMD23 just before the WRITE command if the host wants
to use the pre-erase feature. If not, pre-erase-count might be cleared automatically when another command (ex:
Security Application Commands) is executed.
Send Number of Written Blocks
Systems that use the PipeLine mechanism for data buffers management are, in some cases, unable to determine
which block was the last to be well written to the flash if an error occurs in the middle of a Multiple Blocks Write
operation. The card will respond to ACMD22 with the number of well-written blocks.
Erase
It is desirable to erase many write blocks simultaneously in order to enhance the data throughput. Identification of
these write blocks is accomplished with the ERASE_WR_BLK_START (CMD32), ERASE_WR_BLK_END
(CMD33) commands.
The host must adhere to the following command sequence: ERASE_WR_BLK_START, ERASE_WR_BLK_END
and ERASE (CMD38).
If an erase (CMD38) or address setting (CMD32, 33) command is received out of sequence, the card shall set the
ERASE_SEQ_ERROR bit in the status register and reset the whole sequence.
If an out of sequence command (except SEND_STATUS) is received, the card shall set the ERASE_RESET status
bit in the status register, reset the erase sequence and execute the last command.
If the erase range includes write protected sectors, they shall be left intact and only the non-protected sectors shall
be erased. The WP_ERASE_SKIP status bit in the status register shall be set.
The address field in the address setting commands is a write block address in byte units. The card will ignore all
LSBs below the WRITE_BLK_LEN (see CSD) size.
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Secure Digital (SD) Card Protocol Description
As described above for block write, the card will indicate that an erase is in progress by holding DAT0 low. The
actual erase time may be quite long, and the host may issue CMD7 to deselect the card or perform card
disconnection, as described in the Block Write section, above.
The data at the card after an erase operation is either ‘0’ or ‘1’, depending on the card vendor. The SCR register bit
DATA_STAT_AFTER_ERASE (bit 55) defines whether it is ‘0’ or ‘1’.
4.4.4. Write Protect Management
Three write protect methods are supported in the SD Card as follows:
•
•
•
Mechanical write protect switch (Host responsibility only)
Card internal write protect (Card’s responsibility)
Password protection card lock operation.
4.4.4.1. Mechanical Write Protect Switch
A mechanical sliding tablet on the side of the card (refer to the mechanical description) will be used by the user to
indicate that a given card is write protected or not. If the sliding tablet is positioned in such a way that the window is
open it means that the card is write protected. If the window is close the card is not write protected.
A proper, matched, switch on the socket side will indicate to the host that the card is write-protected or not. It is the
responsibility of the host to protect the card. The position of the write protect switch is un-known to the internal
circuitry of the card.
4.4.4.2. Card’s Internal Write Protection (Optional)
Card data may be protected against either erase or write. The entire card may be permanently write-protected by the
manufacturer or content provider by setting the permanent or temporary write protect bits in the CSD.
4.4.5. Application Specific Commands
The SD Card is defined to be protocol forward compatible to the MultiMediaCard Standard.
The SD Card system is designed to provide a standard interface for a variety application types. In order to keep
future compatibility to the MultiMediaCard standard together with new SD Card specific commands, the SD Card
uses the Application Specific commands feature to implement its proprietary commands. Following is a description
of APP_CMD and GEN_CMD as they were defined in the MultiMediaCard Specification.
Application Specific Command—APP_CMD (CMD55)
This command, when received by the card, will cause the card to interpret the following command as an application
specific command (ACMD). The ACMD has the same structure as regular MultiMediaCard standard commands
and it may have the same CMD number. The card will recognize it as ACMD by the fact that it appears after
APP_CMD.
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Secure Digital (SD) Card Protocol Description
The only effect of the APP_CMD is that if the command index of the immediately following command has an
ACMD overloading it, the non standard version will be used. For example, a card has a definition for ACMD13 but
not for ACMD7. Therefore, if Command 13 is received immediately after APP_CMD command, it would be
interpreted as the non standard ACMD13, whereas command 7, similarly received, would be interpreted as the
standard CMD7. In order to use one of the manufacturer specific ACMDs the host does one of the following:
•
•
Sends APP_CMD. The response will have the APP_CMD bit (new status bit) set signaling to the host
that ACMD is now expected.
Sends the required ACMD. The response will have the APP_CMD bit set, indicating that the accepted
command was interpreted as ACMD. If a non-ACMD is sent then it will be respected by the card as
normal SD Card command and the APP_CMD bit in the Card Status stays clear.
If a non-valid command is sent (neither ACMD nor CMD) then it will be handled as a standard SD Card illegal
command error.
From the SD Card protocol point of view the ACMD numbers will be defined by the manufacturers with some
restrictions. The following ACMD numbers are reserved for the SD Card proprietary applications and may not be
used by any SD Card manufacturer:
ACMD6, ACMD13, ACMD17-25, ACMD38-49, ACMD51.
General Command—GEN_CMD (CMD56)
The bus transaction of the GEN_CMD is the same as the single block read or write commands (CMD24 or
CMD17). The difference is that the argument denotes the direction of the data transfer (rather than the address) and
the data block is not memory payload data but has a vendor specific format and meaning. The card shall be selected
(‘tran_state’) before sending CMD56. The data block size is the BLOCK_LEN that was defined with CMD16. The
response to CMD56 will be R1.
Currently, there are no defined commands or usage for CMD56 in SanDisk’s SD Card, but new commands may be
easily defined and tailored for OEM application specific requirements (upon request to SanDisk).
4.5. Clock Control
The SD Card bus clock signal can be used by the SD Card host to set the cards to energy saving mode or to control
the data flow on the bus. The host is allowed to lower the clock frequency or shut it down.
There are a few restrictions the SD Card host must follow:
•
•
4-14
The bus frequency can be changed at any time (under the restrictions of maximum data transfer
frequency, defined by the SD Card and the identification frequency).
An exception to the above is ACMD41 (SD_APP_OP_COND). After issuing command ACMD41, the
following 1 or 2 procedures shall be done by the host until the card becomes ready.
1) Issue continuous clock in frequency range of 100KHz-400KHz.
2) If the host wants to stop the clock, poll busy bit by ACMD41 command at less than 50ms
intervals.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
100KHz-400KHz Clocks
1) CLK
1st
CMD
2nd
3rd
(ACMD41)
Polling less than 50ms interval
2) CLK
<50ms
1st
CMD
<50ms
2nd
3rd
(ACMD41)
Figure 4-9. Host Procedures Waiting for Card to be Ready
•
•
It is an obvious requirement that the clock must be running for the SD Card to output data or response
tokens. After the last SD Card bus transaction, the host is required to provide eight (8) clock cycles for
the card to complete the operation before shutting down the clock. Following is a list of various SD
Card bus transactions:
−
A command with no response—eight clocks after the host command end bit.
−
A command with response—eight clocks after the card response end bit.
−
A read data transaction—eight clocks after the end bit of the last data block.
−
A write data transaction—eight clocks after the CRC status token.
The host is allowed to shut down the clock of a “busy” card. The SD Card will complete the
programming operation regardless of the host clock. However, the host must provide a clock edge for
the card to turn off its busy signal. Without a clock edge the SD Card (unless previously disconnected
by a deselect command -CMD7) will force the DAT0 line down, permanently.
4.6. Cyclic Redundancy Codes (CRC)
The Cyclic Redundancy Check (CRC) is intended for protecting SD Card commands, responses and data transfer
against transmission errors on the SD Card bus. One CRC is generated for every command and checked for every
response on the CMD line. For data blocks, CRC is generated for each DAT line per transferred block. The CRC is
generated and checked as described in the following:
CRC7
The CRC7 check is used for all commands, for all responses except type R3, and for the CSD and CID registers.
The CRC7 is a 7-bit value and is computed as follows:
generator polynomial: G(x) = x7 + x3 + 1.
M(x) = (first bit) * xn + (second bit) * xn-1 +...+ (last bit) * x0
CRC[6...0] = Remainder [(M(x) * x7) / G(x)]
The first bit is the most significant bit of the corresponding bit string (of the command, response, CID or CSD). The
degree n of the polynomial is the number of CRC protected bits decreased by one. The number of bits to be
protected is 40 for commands and responses (n = 39), and 120 for the CSD and CID (n = 119).
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Secure Digital (SD) Card Protocol Description
Figure 4-10. CRC7 Generator/Checker
CRC16
When one DAT line is used (as in the MultiMediaCard), the CRC16 is used for payload protection in block transfer
mode. The CRC check sum is a 16-bit value and is computed as follows:
generator polynomial G(x) = x16 + x12 +x5 +1
M(x) = (first bit) * xn + (second bit)* xn-1 +...+ (last bit) * x0
CRC[15...0] = Remainder [(M(x) * x16 ) / G(x)]
The first bit is the first data bit of the corresponding block. The degree n of the polynomial denotes the number of
bits of the data block decreased by one. For example, n = 4,095 for a block length of 512 bytes. The generator
polynomial G(x) is a standard CCITT polynomial. The code has a minimal distance d=4 and is used for a payload
length of up to 2,048 bytes (n ≤ 16,383). The same CRC16 method is used in single DAT line mode and in wide bus
mode. In wide bus mode, the CRC16 is done on each line separately.
Figure 4-11. CRC16 Generator/Checker
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Secure Digital (SD) Card Protocol Description
4.7. Error Conditions
The following sections provide valuable information on error conditions.
4.7.1. CRC and Illegal Command
All commands are protected by CRC bits. If the addressed SD Card’s CRC check fails, the card does not respond
and the command is not executed. The SD Card does not change its state, and COM_CRC_ERROR bit is set in the
status register.
Similarly, if an illegal command has been received, an SD Card shall not change its state, shall not respond and shall
set the ILLEGAL_COMMAND error bit in the status register. Only the non-erroneous state branches are shown in
the state diagrams (Figure 5-7 and Figure 5-8). Table 5-11 contains a complete state transition description.
There are different kinds of illegal commands:
•
•
•
Commands belonging to classes not supported by the SD Card (e.g., write commands in read-only
cards).
Commands not allowed in the current state (e.g., CMD9 in Transfer State).
Commands not defined (e.g., CMD5).
4.7.2. Read, Write and Erase Time-out Conditions
The times after which a time-out condition for Read operations occur are (card independent) either 100 times
longer than the typical access times for these operations given below or 100ms. The times after which a time-out
condition for Write/Erase operations occur are (card independent) either 100 times longer than the typical program
times for these operations given below or 250ms. A card shall complete the command within this time period, or
give up and return an error message. If the host does not get any response with the given time out it should assume
the card is not going to respond anymore and try to recover (e.g., reset the card, power cycle, reject). The typical
access and program times are defined as follows:
Read
The read access time is defined as the sum of the two times given by the CSD parameters TAAC and NSAC. These
card parameters define the typical delay between the end bit of the read command and the start bit of the data block.
Write
The R2W_FACTOR field in the CSD is used to calculate the typical block program time obtained by multiplying
the read access time by this factor. It applies to all write/erase commands (e.g., SET(CLEAR)_WRITE_PROTECT,
PROGRAM_CSD(CID) and the block write commands).
Erase
The duration of an erase command will be (order of magnitude) the number of write blocks (WRITE_BL) to be
erased multiplied by the block write delay.
4.8. Commands
The following sections provide valuable information on commands.
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Secure Digital (SD) Card Protocol Description
4.8.1. Command Types
There are four kinds of commands defined to control the SD Card:
•
•
•
•
Broadcast Commands (bc), no response—The broadcast feature is applicable only if all the CMD lines
are connected together in the host. If they are separated then each card will accept it separately on his
turn.
Broadcast Commands with Response (bcr)—response from all cards simultaneously. Since there is no
Open Drain mode in SD Card, this type of command is used only if all the CMD lines are separated.
The command will be accepted and responded to by every card separately.
Addressed (point-to-point) Commands (ac)—no data transfer on DAT.
Addressed (point-to-point) Data Transfer Commands (adtc)—data transfer on DAT.
All commands and responses are sent over the CMD line of the SD Card. The command transmission always starts
with the left bit of the bit string corresponding to the command code word.
4.8.2. Command Format
(Command length 48 bits, 1.92 µs @ 25 MHz)
0
1
bit 5...bit 0
bit 31...bit 0
bit 6...bit 0
1
start bit
host
command
argument
CRC71
end bit
Commands and arguments are listed in Table 5-3 through Table 5-10.
7-bit CRC Calculation: G(x) = x7 + x3 + 1
M(x) = (start bit)∗x39 + (host bit)∗x38 +...+ (last bit before CRC)∗x0
CRC[6...0] = Remainder[(M(x)∗x7)/G(x)]
4.8.3. Command Classes
The command set of the SD Card is divided into several classes (refer to Figure 4-2). Each class supports a set of
SD Card functions.
The supported Card Command Classes (CCC) are coded as a parameter in the card specific data (CSD) register of
each card, providing the host with information on how to access the card.
1)
4-18
7-bit Cyclic Redundancy Check.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
Table 4-2. Card Command Classes (CCCs)
Supported
Commands
0
1
2
3
4
Basic
Reserved
Block
Read
Reserved
Block
Write
CMD0
+
CMD2
+
CMD3
+
CMD4
+
CMD7
+
CMD9
+
CMD10
+
CMD12
+
CMD13
+
CMD15
+
CMD16
+
CMD17
+
CMD18
+
5
6
Erase Write Protection
7
8
9-11
Lock
Card
Application
Specific
Reserved
+
CMD24
+
CMD25
+
CMD27
+
CMD28
+
CMD29
+
CMD30
+
CMD32
+
CMD33
+
CMD38
+
CMD42
+
CMD55
+
CMD56
+
ACMD6
+
ACMD13
+
ACMD22
+
ACMD23
+
ACMD41
+
ACMD42
+
ACMD51
+
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Secure Digital (SD) Card Protocol Description
4.8.4. Detailed Command Description
Tables 4-3 through 4-9 define in detail the SD Card bus commands.
Table 4-3. Basic Commands (Class 0 And Class 1)
Cmd
Index
Type
Argument
Resp
Abbreviation
CMD0
bc
[31:0] don’t care*
-
GO_IDLE_STATE
CMD1
Resets all cards to Idle State.
Reserved
CMD2
bcr
[31:0] don’t care*
R2
ALL_SEND_CID
CMD3
bcr
[31:0] don’t care*
R6
SEND_RELATIVE_
ADDR
CMD41
Not Supported
CMD5
Reserved
CMD6
CMD7
Command Description
Asks any card to send their CID numbers on the
CMD line. (Any card that is connected to the host
will respond.)
Asks the card to publish a new relative address
(RCA).
Reserved
ac
[31:16] RCA
[15:0] don’t care*
R1
(only
from the
selected
card)
SELECT/DESELECT_
CARD
Command toggles a card between the Stand-by
and Transfer states or between the Programming
and Disconnect state.
In both cases the card is selected by its own
relative address and deselected by any other
address; address 0 deselects all. When the RCA
equals 0, the host may do one of the following:
—use other RCA number to perform card deselection or
—re-send CMD3 to change its RCA number to
other then 0 and then use CMD7 with RCA=0 for
card de-selection.
CMD8
Reserved
CMD9
ac
[31:16] RCA
[15:0] don’t care*
R2
SEND_CSD
Addressed card sends its card-specific data (CSD)
on the CMD line.
CMD10
ac
[31:16] RCA
[15:0] don’t care*
R2
SEND_CID
Addressed card sends its card identification (CID)
on the CMD line.
CMD11
adtc
[31:0] data address2
R1
READ_DAT_UNTIL_
STOP
Reads data stream from the card, starting at the
given address, until a STOP_TRANSMISSION
follows.
CMD12
ac
[31:0] don’t care*
R1b3
STOP_
TRANSMISSION
Terminates a multiple block read/write operation.
CMD13
ac
[31:16] RCA
[15:0] don’t care*
R1
SEND_STATUS
Addressed card sends its status register.
CMD14
CMD15
Reserved
ac
[31:16] RCA
[15:0] don’t care*
-
GO_INACTIVE_
STATE
Sets the card to inactive state.
* The bit places must be filled but the value is irrelevant.
1)
2)
3)
4-20
The DSR option (as well as the SET_DSR command) is not supported by the SanDisk SD Card.
The addressing capability @ 8 bit address resolution is 232 = 4 Gbyte.
The card may become busy after this command. Refer to Figure 5-25 for more details.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
Table 4-4. Block Read Commands (Class 2)
Cmd
Index
Type
Argument
Resp
Abbreviation
CMD16
ac
[31:0] block length
R1
SET_BLOCKLEN
Selects a block length (in bytes) for all following
block commands (read and write).1
CMD17
adtc
[31:0] data address
R1
READ_SINGLE_
BLOCK
Reads a block of the size selected by the
SET_BLOCKLEN command.2
CMD18
adtc
[31:0] data address
R1
READ_MULTIPLE_BLOCK
CMD19 –
CMD23
Command Description
Continuously send blocks of data until interrupted
by a stop transmission command.
Reserved
Table 4-5. Block Write Commands (Class 4)
Cmd
Index
Type
Argument
Resp
Abbreviation
CMD24
adtc
[31:0] data address
R1
WRITE_BLOCK
Writes a block of the size selected by the
SET_BLOCKLEN command.3
CMD25
adtc
[31:0] data address
R1
WRITE_MULTIPLE_
BLOCK
Continuously writes blocks of data until a
STOP_TRANSMISSION follows.
CMD26
Command Description
Not Applicable
CMD27
adtc
[31:0] don’t care*
R1
* The bit places must be filled but the value is irrelevant.
PROGRAM_CSD
Programming of the programmable bits of the CSD.
Table 4-6. Write Protection (Class 6)
Cmd
Index
Type
Argument
CMD28*
ac
[31:0] data address
CMD29*
ac
CMD30*
adtc
CMD31
1)
2)
3)
Resp
Abbreviation
Command Description
R1b
SET_WRITE_PROT
This command sets the write protection bit of the
addressed group. The properties of write
protection are coded in the card specific data
(WP_GRP_SIZE).
[31:0] data address
R1b
CLR_WRITE_PROT
This command clears the write protection bit of
the addressed group.
[31:0] write protect
data address
R1
SEND_WRITE_
PROT
This command asks the card to send the status of
the write protection bits.
Reserved
The default block length is as specified in the CSD (512 bytes). A set block length of less than 512 bytes will
cause a write error. The only valid write set block length is 512 bytes. CMD16 is not mandatory if the default is
accepted.
The data transferred must not cross a physical block boundary.
All data blocks are responded to with a data response token followed by a busy signal. The data transferred
must not cross a physical block boundary.
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Secure Digital (SD) Card Protocol Description
Table 4-7. Erase Commands (Class 5)
Cmd
Index
Type
Argument
Resp
Abbreviation
CMD32
ac
[31:0] data
address
R1
ERASE_WR_BLK_START
Sets the address of the first write block to be
erased.
CMD33
ac
[31:0] data
address
R1
ERASE_WR_BLK_END
Sets the address of the last write block of the
continuous range to be erased.
Reserved
CMD34
…
CMD37
CMD38
Command Description
ac
[31:0] don’t care*
R1b
CMD39
…
CMD41
* The bit places must be filled but the value is irrelevant.
ERASE
Erases all previously selected write blocks.
Reserved
Table 4-8. Lock Card Commands (Class 7)
Cmd
Index
Type
Argument
CMD42
….
CMD54
Resp
Abbreviation
Command Description
SDA Optional Commands, currently supported by SanDisk SD Card.
Table 4-9. Application Specific Commands (Class 8)
CMD
INDEX
Type
Argument
Resp.
Abbreviation
CMD55
ac
[31:16] RCA [15:0]
stuff bits
R1
APP_CMD
Indicates to the card that the next command is an
application specific command rather than a
standard command
CMD56
adtc
[31:1] stuff bits.
R1
GEN_CMD
Used either to transfer a data block to the card or
to get a data block from the card for general
purpose / application specific commands. The
size of the data block shall be set by the
SET_BLOCK_LEN command.
[0]: RD/
CMD57 ...
WR1
Command Description
Reserved
CMD59
CMD60 -63
1)
4-22
Reserved for Manufacturer
RD/WR: “1” = the host gets a block of data from the card. “0” = the host sends a block of data to the card.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
Table 4-10 describes all the application specific commands supported/reserved by the SD Card. All the following
ACMDs shall be preceded with APP_CMD command (CMD55).
Table 4-10. Application Specific Commands Used/Reserved by SD Card
ACMD
INDEX
Type
Argument
Resp.
Abbreviation
Command Description
ACMD6
ac
[31:2] stuff bits
[1:0]bus width
R1
SET_BUS_WIDTH
Defines the data bus width (’00’=1bit or ’10’=4 bits bus)
to be used for data transfer.
ACMD13
adtc
[31:0] stuff bits
R1
SD_STATUS
Send the SD Card status. The status fields are given in
Table 4-28.
ACMD17
ACMD18
Reserved
--
--
--
--
Reserved for SD security applications.1
Reserved
ACMD19
to
ACMD21
ACMD22
adtc
[31:0] stuff bits
R1
SEND_NUM_WR_
BLOCKS
ACMD23
ac
[31:23] stuff bits
[22:0]Number of blocks
R1
SET_WR_BLK_
ERASE_COUNT
ACMD24
Send the number of the written (without errors) write
blocks. Responds with 32bit+CRC data block.
Set the number of write blocks to be pre-erased before
writing (to be used for faster Multiple Block WR
command). “1”=default (one wr block)2.
Reserved
ACMD25
--
--
--
--
Reserved for SD security applications.1
ACMD26
--
--
--
--
Reserved for SD security applications.1
ACMD38
--
--
--
--
Reserved for SD security applications.1
Reserved
ACMD39
to
ACMD40
ACMD41
bcr
[31:0]OCR
without busy
R3
SD_APP_OP_COND
Asks the accessed card to send its operating condition
register (OCR) con tent in the response on the CMD
line.
ACMD42
ac
[31:1] stuff bits
[0]set_cd
R1
SET_CLR_CARD_
DETECT
Connect[1]/Disconnect[0] the 50KOhm pull-up resistor
on CD/DAT3 (pin 1) of the card. The pull-up may be
used for card detection.
ACMD43
--
--
--
--
adtc
[31:0] staff bits
R1
SEND_SCR
Reserved for SD security applications.1
ACMD49
ACMD51
Reads the SD Configuration Register (SCR).
NOTES: 1) Refer to SD Card Security Specification for detailed explanation about the SD Security Features
2) Command STOP_TRAN (CMD12) shall be used to stop the transmission in Write Multiple Block whether the preerase (ACMD23) feature is used or not.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
4-23
Secure Digital (SD) Card Protocol Description
4.9. Card State Transition Table
Table 4-11 defines the SD Card state transitions in dependency of the received command.
Table 4-11. Card State Transition Table
Current State
idle
ready
ident
stby
Command
tran
data
rcv
prg
dis
ina
Changes to
Class Independent
CRC error
-
-
-
-
-
-
-
-
-
-
command not sup ported
-
-
-
-
-
-
-
-
-
-
CMD0
idle
idle
idle
idle
idle
idle
idle
idle
idle
-
CMD2
-
ident
-
-
-
-
-
-
-
-
CMD3
-
-
stby
stby
-
-
-
-
-
-
CMD4
-
-
-
stby
-
-
-
-
-
-
CMD7, card is addressed
-
-
-
tran
-
-
-
-
prg
-
CMD7, card is not addressed
-
-
-
stby
stby
stby
-
dis
-
-
CMD9
-
-
-
stby
-
-
-
-
-
-
CMD10
-
-
-
stby
-
-
-
-
-
-
CMD12
-
-
-
-
-
tran
prg
-
-
-
CMD13
-
-
-
stby
tran
data
rcv
prg
dis
-
CMD15
-
-
-
ina
ina
ina
ina
ina
ina
-
CMD16
-
-
-
-
tran
-
-
-
-
-
CMD17
-
-
-
-
data
-
-
-
-
-
CMD18
-
-
-
-
data
-
-
-
-
-
Class 0
Class 2
Class 4
CMD16
See Class 2
CMD24
-
-
-
-
rcv
-
-
-
-
-
CMD25
-
-
-
-
rcv
-
-
-
-
-
CMD27
-
-
-
-
rcv
-
-
-
-
-
CMD28
-
-
-
-
prg
-
-
-
-
-
CMD29
-
-
-
-
prg
-
-
-
-
-
CMD30
-
-
-
-
data
-
-
-
-
-
Class 6
Class 5
4-24
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
Current State
idle
ready
ident
stby
tran
data
rcv
prg
dis
ina
CMD32
-
-
-
-
tran
-
-
-
-
-
CMD33
-
-
-
-
tran
-
-
-
-
-
CMD38
-
-
-
-
prg
-
-
-
-
-
Class 7
CMD42
This is an SDA optional command supported by the SanDisk SD Card.
Class 8
CMD55
idle
-
-
stby
tran
data
rcv
prg
dis
-
CMD56; RD/WR = 0
-
-
-
-
rcv
-
-
-
-
-
CMD56; RD/WR = 1
-
-
-
-
data
-
-
-
-
-
ACMD6
-
-
-
-
tran
-
-
-
-
-
ACMD13
-
-
-
-
tran
-
-
-
-
-
ACMD22
-
-
-
-
tran
-
-
-
-
-
ACMD23
-
-
-
-
tran
-
-
-
-
-
ACMD18,25,26,38,
43,44,45,46,47,48,49
Refer to SD Card Security Specification for an explanation of the SD Security Features. The
SanDisk SD Card supports all the security related commands as explained in the specification.
ready
-
-
-
-
-
-
-
-
-
ACMD41, card is busy
idle
-
-
-
-
-
-
-
-
-
ACMD41, card VDD range not
compatible
ina
-
-
-
-
-
-
-
-
-
ACMD42
-
-
-
-
tran
-
-
-
-
-
ACMD51
-
-
-
-
data
-
-
-
-
-
ACMD41, card VDD range
compatible
class 9- 11
CMD41; CMD43...CMD54,
CMD57-CMD59
CMD60...CMD63
Reserved
Reserved for manufacturer
4.10. Responses
All responses are sent via the CMD line. The response transmission always starts with the MSB. The response
length depends on the response type.
A response always starts with a start bit (always ‘0’), followed by the bit indicating the direction of transmission
(card = ‘0’). A value denoted by ‘x’ in the tables below indicates a variable entry. All responses except for the type
R3 (see below) are protected by a CRC. Every response is terminated by the end bit (always ‘1’).
There are four types of responses that are supported in the SanDisk SD Card. Their formats are defined as follows:
R1 (standard response): response length 48 bit.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
4-25
Secure Digital (SD) Card Protocol Description
Bits 45:40 indicate the index of the command to which it is responding. The status of the card is coded in 32 bits.
Note that when a data transfer to the card is involved, a busy signal may appear on the data line after the
transmission of each block of data. The host will check for busy after the data block transmission.
Table 4-12. Response R1
Bit Position
47
46
[45:40]
[39:8]
[7:1]
0
Width (bits)
1
1
6
32
7
1
Value
‘0’
‘0’
x
x
x
‘1’
start bit
transmission bit
command index
card status
CRC7
end bit
Description
R1b is identical to R1 with an optional busy signal transmitted on the data line. The card may become busy after
receiving these commands based on its state prior to the command reception. The host will check for busy at the
response.
R2 (CID, CSD register): response length 136 bits.
The content of the CID register is sent as a response to CMD2 and CMD10. The content of the CSD register is sent
as a response to CMD9. Only bits [127...1] of the CID and CSD are transferred, bit [0] of these registers is replaced
by the end bit of the response.
Table 4-13. Response R2
Bit Position
135
134
[133:128]
[127:1]
0
Width (bits)
1
1
6
127
1
Value
‘0’
‘0’
‘111111’
x
‘1’
start bit
transmission bit
reserved
CID or CSD register incl.
internal CRC7
end bit
Description
R3 (OCR register): response length 48 bits.
The contents of the OCR register are sent as a response to ACMD41.
Table 4-14. Response R3
Bit Position
47
46
[45:40]
[39:8]
[7:1]
0
Width (bits)
1
1
6
32
7
1
Value
‘0’
‘0’
‘111111’
x
‘1111111’
‘1’
start bit
transmission bit
reserved
OCR register
reserved
end bit
Description
R4 and R5: responses are not supported.
R6 (Published RCA response): code length 48-bit. The bits 45:40 indicate the index of the command to be
responded to—in that case it will be ‘000011’ (together with bit 5 in the status bits it means = CMD3). The 16 MSB
bits of the argument field are used for the published RCA number.
4-26
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
Table 4-15. R6 Response
Bit Position
47
46
[45:40]
Width (bits)
1
1
6
16
Value
‘0’
‘0’
x
x
start bit
transmission bit
Command
index
(‘000011’)
Description
[39:8] Argument Field
[7:1]
0
16
7
1
x
x
‘1’
CRC7
end bit
New published RCA [15:0] card status bits:
[31:16] of the card
23,22,19,12:0
(see Table 4-28)
4.11. Timings
All timing diagrams use the schematics and abbreviations listed in Table 4-16.
Table 4-16. Timing Diagram Symbols
S
Start Bit (= 0)
T
Transmitter Bit (Host = 1, Card = 0)
P
One-cycle Pull-up (= 1)
E
End Bit (=1)
Z
High Impedance State (-> = 1)
D
Data Bits
X
Don’t Care Data Bits (from Card)
*
Repeater
CRC
Cyclic Redundancy Check Bits (7 Bits)
Card Active
Host Active
The difference between the P-bit and Z-bit is that a P-bit is actively driven to HIGH by the card respectively host
output driver, while Z-bit is driven to (respectively kept) HIGH by the pull-up resistors RCMD respectively RDAT.
Actively-driven P-bits are less sensitive to noise. All timing values are defined in Table 4-17.
4.11.1. Command and Response
Both host command and card responses are clocked out with the rising edge of the host clock.
Card identification and card operation conditions timing
The timing for CMD2 and ACMD41 is given bellow. The command is followed by a period of two Z bits (allowing
time for direction switching on the bus) and then by P bits pushed up by the responding card. The card response to
the host command starts after NID clock cycles.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
4-27
Secure Digital (SD) Card Protocol Description
CMD
<------Host command ---->
<-NID cycles ->
S T
content
CRC E Z Z P * * * P S T
<--- CID or OCR --->
content
Z Z Z
Figure 4-12. Identification Timing (Card Identification Mode)
Assign a card relative address
The SEND_RELATIVE_ADDR (CMD 3) for SD Card timing is given bellow. Note that CMD3 command’s
content, functionality and timing are different for MultiMediaCard. The minimum delay between the host command
and card response is NCR clock cycles.
CMD
<---- Host command ---->
<-NCR cycles->
<-------- Response --------->
S T
content
CRC E Z Z P * * * P S T
content
CRC E Z Z Z
Figure 4-13 SEND_RELATIVE_ADDR Timing
Data transfer mode
After the card published it own RCA it will switch to data transfer mode. The command is followed by a period of
two Z bits (allowing time for direction switching on the bus) and then by P bits pushed up by the responding card.
This timing diagram is relevant for all responded host commands except and ACMD41 and CMD2.
CMD
<---- Host command ----> <-NCR cycles-> <-------- Response --------->
S T
content
CRC E Z Z P * * * P S T
content
CRC E Z Z Z
Figure 4-13. Command Response Timing (Data Transfer Mode)
Last Card Response—Next Host Command Timing
After receiving the last card response, the host can start the next command transmission after at least NRC clock
cycles. This timing is relevant for any host command.
CMD
<-------- Response -------->
<-NRC cycles->
<---- Host command ----->
S T
content
CRC E Z * * * * * * Z S T
content
CRC E
Figure 4-14. Timing Response End to Next CMD Start (Data Transfer Mode)
Last Host Command—Next Host Command Timing
After the last command has been sent, the host can continue sending the next command after at least NCC clock
periods.
CMD
<----- Host command ---->
<-NCC cycles->
<---- Host command ----->
S T
content
CRC E Z * * * * * * Z S T
content
CRC E
Figure 4-15. Timing of Command Sequences (All Modes)
4.11.2. Data Read
Note that the DAT line represents the data bus (either 1 or 4 bits).
Single Block Read
The host selects one card for data read operation by CMD7, and sets the valid block length for block oriented data
transfer by CMD16. The basic bus timing for a read operation is given in Figure 5-17. The sequence starts with a
single block read command (CMD17) which specifies the start address in the argument field. The response is sent
on the CMD line as usual.
4-28
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
CMD
DAT
<----- Host command ----->
<-NCR cycles->
<-------- Response --------->
S T
content
CRC E Z Z P * * * P S T
content
CRC E
<------- NAC cycles ------->
<- Read Data
Z Z Z **** Z Z Z Z Z Z P
**** ****
P S D D D ***
Figure 4-16. Timing of Single Block Read
Data transmission from the card starts after the access time delay NAC beginning from the end bit of the read
command. After the last data bit, the CRC check bits are suffixed to allow the host to check for transmission errors.
Multiple Block Read
In multiple block read mode, the card sends a continuous flow of data blocks following the initial host read
command. The data flow is terminated by a stop transmission command (CMD12). Figure 4-17 describes the timing
of the data blocks and Figure 4-18 describes the response to a stop command. The data transmission stops two clock
cycles after the end bit of the stop command.
CMD
DAT
<-- Host command --->
<-NCR cycles->
<---- Response ------>
S T
content
CRC E Z Z P * P S T
content
CRC E Z Z P P P P P P P P P P P P P
<--- NAC cycles ---->
<-- Read Data -->
<- NAC cycles ->
<- Read Data ->
Z Z Z *** Z Z Z Z Z Z P ****** P S
content
CRC E P * * * * * * P S D D D D D
Figure 4-17. Timing of Multiple Block Read Command
CMD
<----- Host command ----->
<-NCR cycles->
<-------- Response --------->
S T
content
CRC E Z Z P * * * P S T
content
CRC E
DAT
D D D
*******
D D D E Z Z
******************
Figure 4-18. Timing of Stop Command (CMD12, Data Transfer Mode)
4.11.3. Data Write
Single Block Write
The host selects one card for data write operation by CMD7. The host sets the valid block length for block-oriented
data transfer by CMD16.
The basic bus timing for a write operation is given in Figure 5-20. The sequence starts with a single block write
command (CMD24) that determines (in the argument field) the start address. It is responded by the card on the
CMD line as usual. The data transfer from the host starts NWR clock cycles after the card response was received.
The data is suffixed with CRC check bits to allow the card to check it for transmission errors. The card sends back
the CRC check result as a CRC status token on the DAT0 line. In the case of transmission error the card sends a
negative CRC status (‘101’). In the case of non-erroneous transmission the card sends a positive CRC status (‘010’)
and starts the data programming procedure. When a flash programming error occurs the card will ignore all further
data blocks. In this case no CRC response will be sent to the host and, therefore, there will not be CRC start bit on
the bus and the three CRC status bits will read (‘111‘).
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
4-29
Secure Digital (SD) Card Protocol Description
<-Host cmnd->
<- NCR ->
<-Card response >
CMD
E Z Z P * P S T Content CRC E Z Z P
****************
P P P P P P P P
<-NWR->
<- Write data ->
CRC status
<- Busy ->
DAT0
Z Z * * * * * * Z Z Z * * * Z Z Z Z P * P S content CRC E Z Z S Status E S L*L E Z
DAT1-3
Z Z * * * * * * Z Z Z * * * Z Z Z Z P * P S content CRC E Z Z X X X X X X X X X Z
Figure 4-19. Timing of the Block Write Command
Note that the CRC response output is always two clocks after the end of data.
If the card does not have a free data receive buffer, the card indicates this condition by pulling down the data line to
LOW. The card stops pulling down the DAT0 line as soon as at least one receive buffer for the defined data transfer
block length becomes free. This signaling does not give any information about the data write status, which must be
polled by the host.
Multiple Block Write
In multiple block write mode, the card expects continuous flow of data blocks following the initial host write
command.
As in the case of single block write, the data is suffixed with CRC check bits to allow the card to check it for
transmission errors. The card sends back the CRC check result as a CRC status token on the DAT0 line. In the case
of transmission error the card sends a negative CRC status (‘101’). In the case of non-erroneous transmission the
card sends a positive CRC status (‘010’) and starts the data programming procedure. When a flash programming
error occurs the card will ignore all further data blocks. In this case no CRC response will be sent to the host and,
therefore, there will not be CRC start bit on the bus and the three CRC status bits will read (‘111‘).
The data flow is terminated by a stop transmission command (CMD12). Figure 4-20 describes the timing of the data
blocks with and without card busy signal.
<-CardRsp->
CMD
E Z Z P
***************
P P P P P
***************
P P P P P P P P P
<-NWR-> <- Write data ->
CRC status <-NWR-> <- Write data ->
CRC status <- Busy -> <-NWR->
DAT
Z Z P * P S Data+CRC E Z Z S Status E Z P * P S Data+CRC E Z Z S Status E S L*L E Z P*P
Figure 4-20. Timing of the Multiple Block Write Command
The stop transmission command works similar as in the read mode. Figures 4-21 through 4-24 describe the timing
of the stop command in different card states.
<---- Host Command ---->
CMD
DAT
S T
content
< Ncr Cycles >
<----- Card response----->
P******P
S T
content
CRC E
<---------- Card is programming ---------->
D D D D D D D D D D E Z Z S L
*********************
<Host Cmnd>
CRC E Z Z P
S T
Content
E Z Z Z Z Z Z Z Z
Figure 4-21. Stop Transmission During Data Transfer from the Host
The card will treat a data block as successfully received and ready for programming only if the CRC data of the
block was validated and the CRC status token sent back to the host. Figure 4-22 is an example of an interrupted (by
a host stop command) attempt to transmit the CRC status block. The sequence is identical to all other stop
transmission examples. The end bit of the host command is followed, on the data line, with one more data bit, end
bit and two Z clock for switching the bus direction. The received data block, in this case is considered incomplete
and will not be programmed.
4-30
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Secure Digital (SD) Card Protocol Description
CMD
DAT
<---- Host Command ---->
< Ncr Cycles >
<----- Card response----->
S T
content
CRC E Z Z P
P******P
S T
content
CRC E
--Data block->
CRC Status1
Å------------Card is programming ----------Æ
D D D D D Z Z S Status E Z Z S L
* * * * * * ** * * * * * * * * * * * *
S T
<Host Cmnd>
Content
E Z Z Z Z Z Z Z Z
1) The card CRC status response was interrupted by the host.
Figure 4-22. Stop Transmission During CRC Status Transfer from the Card
All previous examples dealt with the scenario of the host stopping the data transmission during an active data
transfer. The following two diagrams describe a scenario of receiving the stop transmission between data blocks. In
the first example the card is busy programming the last block while in the second the card is idle. However, there
are still unprogrammed data blocks in the input buffers. These blocks are being programmed as soon as the stop
transmission command is received and the card activates the busy signal.
CMD
DAT
<---- Host Command ---->
< Ncr Cycles >
<----- Card response----->
S T
content
CRC E Z Z P * * * P S T
content
CRC E
<---------- Card is programming ---------->
S L
* * * * * * * * * * * * * * * * * * * * * * * ** ** * * * * * * * * *
<Host Cmnd>
S T
Content
L E Z Z Z Z Z Z Z Z
Figure 4-23. Stop Transmission Received After Last Data Block. Card is Busy Programming
CMD
DAT
<---- Host Command ---->
< Ncr Cycles >
<----- Card response----->
S T content
CRC E Z Z P * * * P S T
content
CRC E
<---------- Card is programming ---------->
Z Z Z Z Z Z Z Z Z Z Z S L
* ************************* *
<Host Cmnd>
S T
Content
L E Z Z Z Z Z Z Z Z
Figure 4-24. Stop Transmission Received After Last Data Block. Card becomes Busy
Erase, Set and Clear Write Protect Timing
The host must first tag the start (CMD32) and end (CMD33) addresses of the range to be erased. The erase
command (CMD38), once issued, will erase all the selected write blocks. Similarly, set and clear write protect
commands start a programming operation as well. The card will signal “busy” (by pulling the DAT line low) for the
duration of the erase or programming operation. The bus transaction timings are the same as given for stop tran
command in Figure 4-23.
Reselecting a Busy Card
When a busy card, which is currently in the dis state, is reselected it will reinstate its busy signaling on the data line.
The timing diagram for this command/response/busy transaction is the same as given for stop tran command in
Figure 4-24.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
4-31
Secure Digital (SD) Card Protocol Description
4.11.4. Timing Values
Table 4-17 defines all timing values. For more information, refer to Table 5-5 and 5.1.9.2 in Section 5.0, and the
applications note in Appendix A, “Host Design Considerations: NAND MMC and SD-based Products.”
Table 4-17. Timing Values
Min.
Max.
Unit
NCR
2
64
Clock Cycles
NID
5
5
Clock Cycles
NAC
2
See note.
Clock Cycles
NRC
8
-
Clock Cycles
NCC
8
-
Clock Cycles
NWR
2
-
Clock Cycles
NOTE: min [{(TAAC ∗ f ) + (NSAC ∗ 100)}, {(100ms ∗ f)}] where units = (clocks) and “f” is the clock frequency.
4-32
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
5. SPI Protocol Definition
5.1. SPI Bus Protocol
While the SD Card channel is based on command and data bit-streams, which are initiated by a start bit and
terminated by a stop bit, the SPI channel is byte oriented. Every command or data block is built of eight bit bytes
and is byte aligned (multiples of eight clocks) to the CS signal.
Similar to the SD Bus protocol, the SPI messages are built from command, response and data-block tokens. All
communication between host and cards is controlled by the host (master). The host starts every bus transaction by
asserting the CS signal low.
The response behavior in SPI Bus mode differs from the SD Bus mode in the following three ways:
•
•
•
The selected card always responds to the command.
An eight or 16-bit response structure is used.
When the card encounters a data retrieval problem, it will respond with an error response (which
replaces the expected data block) rather than time-out as in the SD Bus mode.
In addition to the command response, every data block sent to the card during write operations will be responded
with a special data response token. A data block may be as big as one card write block (WRITE_BL_LEN) and as
small as a single byte.1
5.1.1. Mode Selection
The SD Card wakes up in the SD Bus mode. It will enter SPI mode if the CS signal is asserted (negative) during the
reception of the reset command (CMD0). If the card recognizes that the SD Bus mode is required it will not respond
to the command and remain in the SD Bus mode. If SPI mode is required, the card will switch to SPI mode and
respond with the SPI mode R1 response.
The only way to return to the SD Bus mode is by power cycling the card. In SPI mode, the SD Card protocol state
machine is not observed. All the SD Card commands supported in SPI mode are always available.
The default command structure/protocol for SPI mode is that CRC checking is disabled. Since the card powers up in
SD Bus mode, CMD0 must be followed by a valid CRC byte (even though the command is sent using the SPI
structure). Once in SPI mode, CRCs are disabled by default.
CMD0 is a static command and always generates the same 7-bit CRC of 4Ah. Adding the “1,” end bit (bit 0) to the
CRC creates a CRC byte of 95h. The following hexadecimal sequence can be used to send CMD0 in all situations
for SPI mode, since the CRC byte (although required) is ignored once in SPI mode. The entire CMD0 sequence
appears as 40 00 00 00 00 95 (hexadecimal).
1)
The default block length is as specified in the CSD (512 bytes). A set block length of less than 512 bytes will
cause a write error. The only valid write set block length is 512 bytes. CMD16 is not mandatory if the default is
accepted.
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SPI Protocol Definition
5.1.2. Bus Transfer Protection
Every SD Card token transferred on the bus is protected by CRC bits. In SPI mode, the SD Card offers a non
protected mode which enables systems built with reliable data links to exclude the hardware or firmware required
for implementing the CRC generation and verification functions.
In the non-protected mode the CRC bits of the command, response and data tokens are still required in the tokens
however, they are defined as “don’t care” for the transmitters and ignored by the receivers.
The SPI interface is initialized in the non-protected mode. The host can turn this option on and off using
CRC_ON_OFF command (CMD59).
The CRC7/CRC16 polynomials are identical to that used in SD Bus mode. Refer to this section in the SD Bus mode
chapter.
5.1.3. Data Read
SPI mode supports single block and multiple block read operations (SD Card CMD17 or CMD18). Upon reception
of a valid read command the card will respond with a response token followed by a data token in the length defined
in a previous SET_BLOCK_LENGTH (CMD16) command (see Figure 5-1).
Next Command
From Host
to Card
Data from
Card to Host
From Card
to Host
DataIn
Command
DataOut
Command
Response
Data Block
CRC
Figure 5-1. Single Block Read Operation
A valid data block is suffixed with a 16-bit CRC generated by the standard CCITT polynomial:
x16+x12+x5+1.
The maximum block length is 512 bytes as defined by READ_BL_LEN (CSD parameter). Block lengths can be any
number between 1 and READ_BL_LEN.
The start address can be any byte address in the valid address range of the card. Every block, however, must be
contained in a single physical card sector.
In case of data retrieval error, the card will not transmit any data. Instead, a special data error token will be sent to
the host. Figure 5-2 shows a data read operation, which terminated with an error token rather than a data block.
5-2
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SPI Protocol Definition
Figure 5-2. Read Operation—Data Error
In the case of a Multiple Block Read operation, every transferred block has a 16-bit CRC suffix. The Stop
Transmission command (CMD12) will actually stop the data transfer operation (the same as in SD Bus mode).
Stop
Transmission
command
From host
to card(s)
From card
to host
DataIn
Data from
card to host
Command
Command
Response
DataOut
From card
to host
Data Block
CRC
Data Block
CRC
Response
Figure 5-3. Multiple Block Read Operation
5.1.4. Data Write
In SPI mode, the SD Card supports single block or multiple block write operations. Upon reception of a valid write
command (SD Card CMD24 or CMD25), the card will respond with a response token and will wait for a data block
to be sent from the host. CRC suffix and start address restrictions are identical to the read operation (see
Figure 5-4). The only valid block length, however, is 512 bytes. Setting a smaller block length will cause a write
error on the next write command.
From host
to card
DataIn
DataOut
From card
to host
Data from
host to
card
Start block
token
Command
Data
response
and busy
from card
Data Block
Response
New
command
from host
Command
Response
Busy
Figure 5-4. Single Block Write Operation
Every data block has a prefix or ‘start block’ token (one byte). After a data block is received the card will respond
with a data-response token, and if the data block is received with no errors, it will be programmed. As long as the
card is busy programming, a continuous stream of busy tokens will be sent to the host (effectively holding the
dataOut line low).
Once the programming operation is completed, the host must check the results of the programming using the
SEND_STATUS command (CMD13). Some errors (e.g., address out of range, write protect violation, etc.) are
detected during programming only. The only validation check performed on the data block and communicated to
the host via the data-response token is CRC and general Write Error indication.
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5-3
SPI Protocol Definition
In Multiple Block write operation the stop transmission will be done by sending ’Stop Tran’ token instead of ’Start
Block’ token at the beginning of the next block. In case of Write Error indication (on the data response) the host
shall use SEND_NUM_WR_BLOCKS (ACMD22) in order to get the number of well written write blocks. The data
token’s description is given in Section 5.2.4.
From host
to card
DataIn
DataOut
From card
to host
Start block
token
Data from
host to
card
Data
response
and busy
from card
Response
Stop tran
token
Data
Block
Data
Block
Command
Data from
host to
card
Data_Response Busy
Data_Response Busy
Busy
Figure 5-5. Multiple Block Write Operation
Resetting the CS signal while the card is busy does not terminate the programming process. The card releases the
dataOut line (tristate) and continue to program. If the card is reselected before the programming is done, the dataOut
line will be forced back to low and all commands will be rejected.
Resetting a card (using CMD0) will terminate any pending or active programming operation. This may destroy the
data formats on the card. It is the host’s responsibility to prevent it.
5.1.5. Erase and Write Protect Management
The erase and write protect management procedures in the SPI mode are identical to the SD Bus mode. While the
card is erasing or changing the write protection bits of the predefined sector list it will be in a busy state and will
hold the dataOut line low. Figure 5-6 illustrates a “no data” bus transaction with and without busy signaling.
From Host
to Card
From Host
to Card
From Card
to Host
DataIn
Command
From Card
to Host
Command
Response
DataOut
Response
Busy
Figure 5-6. “No Data” Operations
5.1.6. Read CID/CSD Registers
Unlike the SD Bus protocol (where the register contents are sent as a command response), reading the contents of
the CSD and CID registers in SPI mode is a simple read-block transaction. The card will respond with a standard
response token followed by a data block of 16 bytes suffixed with a 16-bit CRC.
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SPI Protocol Definition
The data time out for the CSD command cannot be set to the card TAAC since this value is stored in the CSD.
Therefore, the standard response time-out value (NCR) is used for read latency of the CSD register.
5.1.7. Reset Sequence
The SD Card requires a defined reset sequence. After power on reset or CMD0 (software reset), the card enters an
idle state. At this state, the only legal host commands are CMD1 (SEND_OP_COND), ACMD41
(SD_SEND_OP_COND), CMD59 (CRC_ON_OFF) and CMD58 (READ_OCR).
The host must poll the card (by repeatedly sending CMD1) until the ‘in-idle-state’ bit in the card response indicates
(by being set to 0) that the card completed its initialization processes and is ready for the next command.
In SPI mode, however, CMD1 has no operands and does not return the contents of the OCR register. Instead, the
host can use CMD58 (SPI Mode Only) to read the OCR register. It is the responsibility of the host to refrain from
accessing cards that do not support its voltage range.
The use of CMD58 is not restricted to the initialization phase only, but can be issued at any time. The host must poll
the card (by repeatedly sending CMD1) until the ‘in-idle-state’ bit in the card response indicates (by being set to 0)
that the card has completed its initialization process and is ready for the next command.
5.1.8. Clock Control
The SPI bus clock signal can be used by the SPI host to set the cards to energy-saving mode or to control the data
flow (to avoid under-run or over-run conditions) on the bus. The host is allowed to change the clock frequency or
shut it down.
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5-5
SPI Protocol Definition
There are a few restrictions the SPI host must follow:
•
•
•
The bus frequency can be changed at any time (under the restrictions of maximum data transfer
frequency, defined by the SD Cards).
It is an obvious requirement that the clock must be running for the SD Card to output data or response
tokens. After the last SPI bus transaction, the host is required to provide 8 (eight) clock cycles for the
card to complete the operation before shutting down the clock. Throughout this 8-clock period, the
state of the CS signal is irrelevant. It can be asserted or de-asserted. Following is a list of the various
SPI bus transactions:
−
A command/response sequence. Eight clocks after the card response end bit. The CS signal can be
asserted or de-asserted during these 8 clocks.
−
A read data transaction. Eight clocks after the end bit of the last data block.
−
A write data transaction. Eight clocks after the CRC status token.
The host is allowed to shut down the clock of a “busy” card. The SD Card will complete the
programming operation regardless of the host clock. However, the host must provide a clock edge for
the card to turn off its busy signal. Without a clock edge, the SD Card (unless previously disconnected
by de-asserting the CS signal) will force the dataOut line down, permanently.
5.1.9. Error Conditions
The following sections provide valuable information on error conditions.
5.1.9.1. CRC and Illegal Commands
Unlike the SD Card protocol, in SPI mode the card will always respond to a command. The response indicates
acceptance or rejection of the command. A command may be rejected in any one of the following cases:
•
•
•
•
•
•
•
It is sent while the card is in read operation (except CMD12 which is legal).
It is sent while the card is in Busy.
Card is locked and it is other than Class 0 or 7 commands.
It is not supported (illegal opcode).
CRC check failed.
It contains an illegal operand.
It was out of sequence during an erase sequence.
Note that in case the host sends command while the card sends data in read operation then the response with an
illegal command indication may disturb the data transfer.
5.1.9.2. Read, Write and Erase Time-out Conditions
The times after which a time-out condition for read operations occur are (card independent) either 100 times longer
than the typical access times for these operations given below or 100ms. The times after which a time-out condition
for Write/Erase operations occur are (card independent) either 100 times longer than the typical program times for
these operations given below or 250ms. A card shall complete the command within this time period, or give up and
return an error message. If the host does not get any response with the given time out it should assume the card is
not going to respond anymore and try to recover (for example; reset the card, power cycle, reject). The typical
access and program times are defined in the following sections.
For more information, refer to Table 4-17 in Section 4.0, Table 5-5 in Section 5.0 and the applications note in
Appendix A, “Host Design Considerations: NAND MMC and SD-based Products.”
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SPI Protocol Definition
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5-7
SPI Protocol Definition
Read
The read access time is defined as the sum of the two times given by the CSD parameters TAAC and NSAC. These
card parameters define the typical delay between the end bit of the read command and the start bit of the data block.
Write
The R2W_FACTOR field in the CSD is used to calculate the typical block program time obtained by multiplying
the read access time by this factor. It applies to all write/erase commands (e.g., SET (CLEAR)_WRITE_PROTECT,
PROGRAM_CSD (CID) and the block write commands).
Erase
The duration of an erase command will be (order of magnitude) the number of write blocks (WRITE_BL) to be
erased multiplied by the block write delay.
5.1.10. Memory Array Partitioning
Same as for SD Card mode.
5.1.11. Card Lock/Unlock
The Card Lock/Unlock feature is currently in the SanDisk SD Card.
5.1.12. Application Specific Commands
The Application Specific commands are identical to SD mode with the exception of the APP_CMD status bit (see
Section 3.5.5), which is not available in SPI.
5.1.13. Copyright Protection Commands
All the special Copyright Protection ACMDs and security functionality are the same as for SD mode.
5.2. SPI Command Set
The following sections provide valuable information on the SPI Command Set.
5.2.1. Command Format
All the SD Card commands are 6 bytes long and transmitted MSB first.
Byte 1
5-8
7
6
0
1
Bytes 2—5
5
0
Command
31
Byte 6
0
Command Argument
7
0
CRC
1
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
SPI Protocol Definition
Commands and arguments are listed in Table 5-2.
7-bit CRC Calculation: G(x) = x7 + x3 + 1
M(x) = (start bit)∗x39 + (host bit)∗x38 +...+ (last bit before CRC)∗x0
CRC[6...0] = Remainder[(M(x)∗x7)/G(x)]
5.2.2. Command Classes
As in SD mode, the SPI commands are divided into several classes (See Table 5-1). Each class supports a set of
card functions. An SD Card will support the same set of optional command classes in both communication modes
(there is only one command class table in the CSD register). The available command classes, and the supported
commands for a specific class, however, are different in the SD Card and the SPI communication mode.
Note that except the classes that are not supported in SPI mode (class 1, 3 and 9), the mandatory required classes for
the SD mode are the same for the SPI mode.
Table 5-1. Command Classes in SPI Mode
Card CMD Class
(CCC)
Class Description
Supported Commands
0 1 9 10 12 13 16 17 18 24 25 27 28 29 30 32 33 38 42 55 56 58 59
class 0
Basic
class 1
Not supported in SPI
class 2
Block read
class 3
Not supported in SPI
class 4
Block write
class 5
Erase
class 6
Write-protection (Optional)
class 7
Lock Card (Optional)*
class 8
Application specific
class 9
Not supported in SPI
class 10-11
Reserved
+ + + + + +
+ +
+ + +
+ + +
+ + +
+ + +
+
+ +
* The Lock Card command is supported in the SD Card.
5.2.2.1. Detailed Command Description
The following table provides a detailed description of the SPI bus commands. The responses are defined in Section
5.2.3. Table 5-2 lists all SD Card commands. A “yes” in the SPI mode column indicates that the command is
supported in SPI mode. With these restrictions, the command class description in the CSD is still valid. If a
command does not require an argument, the value of this field should be set to zero. The reserved commands are
reserved in SD Card mode as well.
The binary code of a command is defined by the mnemonic symbol. As an example, the content of the Command
field for CMD0 is (binary) ‘000000’ and for CMD39 is (binary) ‘100111.’
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5-9
SPI Protocol Definition
Table 5-2. Description of SPI Bus Commands
CMD
INDEX
SPI
Mode
Argument
Resp
Abbreviation
CMD0
Yes
None
R1
GO_IDLE_STATE
Resets the SD Card
CMD1
Yes
None
R1
SEND_OP_COND
Activates the card’s initialization process.
CMD2
No
CMD3
No
CMD4
No
CMD5
Reserved
CMD6
Reserved
CMD7
Command Description
No
CMD8
Reserved
CMD9
Yes
None
R1
SEND_CSD
Asks the selected card to send its card-specific
data (CSD).
CMD10
Yes
None
R1
SEND_CID
Asks the selected card to send its card
identification (CID).
CMD11
No
CMD12
Yes
None
R1b
STOP
_TRANSMISSION
CMD13
Yes
None
R2
SEND_STATUS
Asks the selected card to send its status register.
CMD14
No
CMD15
No
CMD16
Yes
[31:0] block length
R1
SET_BLOCKLEN
Selects a block length (in bytes) for all following
block commands (read & write).1
CMD17
Yes
[31:0] data address
R1
READ_SINGLE
_BLOCK
CMD18
Yes
[31:0] data address
R1
READ_MULTIPLE
_BLOCK
CMD19
CMD20
Reserved
Yes
[31:0] data address
R13
WRITE_BLOCK
CMD25
Yes
[31:0] data address
R1
WRITE_MULTIPLE_BLOCK
3)
4)
5-10
Continuously transfers data blocks from card to
host until interrupted by a STOP_
TRANSMISSION command.
No
CMD24
2)
Reads a block of the size selected by the
SET_BLOCKLEN command.2
Reserved
CMD21
...
CMD23
1)
Forces the card to stop transmission during a
multiple block read operation.
Writes a block of the size selected by the
SET_BLOCKLEN command.4
Continuously writes blocks of data until a stop
transmission token is sent (instead of ‘start block’).
The only valid block length for write is 512 bytes. The valid block length for read is 1 to 512 bytes. A set block
length of less than 512 bytes will cause a write error. The card has a default block length of 512 bytes. CMD16 is
not mandatory if the default is accepted.
The start address and block length must be set so that the data transferred will not cross a physical block
boundary.
Data followed by data response plus busy.
The start address must be aligned on a sector boundary. The block length is always 512 bytes.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
SPI Protocol Definition
CMD
INDEX
SPI
Mode
Argument
Resp
Abbreviation
Command Description
CMD26
No
CMD27
Yes
None
R1
PROGRAM_CSD
Programming of the programmable bits of the CSD.
CMD281
Yes
[31:0] data address
R1b
SET_WRITE_PROT
If the card has write protection features, this
command sets the write protection bit of the
addressed group. The properties of write protection
are coded in the card specific data
(WP_GRP_SIZE).
CMD294
Yes
[31:0] data address
R1b
CLR_WRITE_PROT
If the card has write protection features, this
command clears the write protection bit of the
addressed group.
CMD30
Yes
[31:0] write protect
data address
R1
SEND_WRITE_
PROT
CMD31
If the card has write protection features, this
command asks the card to send the status of the
write protection bits.2
Reserved
CMD32
Yes
[31:0] data address
R1
ERASE_WR_BLK_START
_ADDR
Sets the address of the first write block to be
erased.
CMD33
Yes
[31:0] data address
R1
ERASE_WR_BLK_END
_ADDR
Sets the address of the last write block in a
continuous range to be erased.
Reserved
CMD34
….
CMD37
CMD38
Yes
CMD39
No
CMD40
No
[31:0] don’t care*
R1b
CMD41 ...
CMD54
ERASE
Erases all previously selected write blocks.
Reserved
CMD55
Yes
[31:0] stuff bits
R1
APP_CMD
Notifies the card that the next command is an
application specific command rather than a
standard command.
CMD56
Yes
[31:0] stuff bits
[0]: RD/WR.3
R1
GEN_CMD
Used either to transfer a Data Block to the card or
to get a Data Block from the card for general
purpose/application specific commands. The size
of the Data Block is defined with
SET_BLOCK_LEN command.
CMD57
Reserved
CMD58
Yes
None
R3
READ_OCR
CMD59
Yes
[31:1] don’t care*
[0:0] CRC option
R1
CRC_ON_OFF
CMD60-63
* The bit places must be filled but the values are irrelevant.
1)
2)
3)
Reads the OCR register of a card.
Turns the CRC option on or off. A ‘1’ in the CRC
option bit will turn the option on, a ‘0’ will turn it off.
No
These features are not currently supported in the SanDisk SD Card.
32 write protection bits (representing 32 write protect groups starting at the specified address) followed by 16
CRC bits are transferred in a payload format via the data line.
RD/WR_: “1”=the host will get a block of data from the card. “0”=the host sends a block of data to the card.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
5-11
SPI Protocol Definition
Table 5-3 describes all the application specific commands supported or reserved by the SD Card. All the following
commands should be preceded with APP_CMD (CMD55).
Table 5-3. Application Specific Commands Used or Reserved by the SD Card–SPI Mode
CMD
INDEX
SPI Mode
ACMD6
No
ACMD13
Yes
Argument
Resp
Abbreviation
[31:0] stuff bits
R2
SD_STATUS
ACMD17
ACMD18
Command Description
Send the SD Card status. The status fields are
given in Table 4-21
Reserved
Yes
--
--
--
Reserved for SD security applications1
Reserved
ACMD19
to
ACMD21
ACMD22
Yes
[31:0] stuff bits
R1
SEND_NUM_WR_ BLOCKS
ACMD23
Yes
[31:23] stuff bits
[22:0]Number of blocks
R1
SET_WR_BLK_
ERASE_COUNT
ACMD24
Send the numbers of the well-written (without
errors) blocks. Responds with 32bit+CRC data
block.
Set the number of write blocks to be pre-erased
before writing (to be used for faster Multiple Block
WR command). “1”=default (one wr block)(2).
Reserved
ACMD25
Yes
--
--
--
Reserved for SD security applications1
ACMD26
Yes
--
--
--
Reserved for SD security applications1
ACMD38
Yes
--
--
--
Reserved for SD security applications1
Reserved
ACMD39
to
ACMD40
ACMD41
Yes
None
R1
SEND_OP_
COND
ACMD42
Yes
[31:1] stuff bits
R1
SET_CLR_CARD_
DETECT
[0]set_cd
ACMD43
...
ACMD49
Yes
--
--
--
ACMD51
Yes
[31:0] staff bits
R1
SEND_SCR
Activates the card’s initialization process.
Connect[1]/Disconnect[0] the 50KOhm pull-up
resistor on CD/DAT3 (pin 1) of the card. The pull-up
may be used for card detection.
Reserved for SD security applications.1
Reads the SD Configuration Register (SCR).
NOTES: (1) Refer to “SD Card Security Specification” for detailed explanation about the SD Security Features
(2) Command STOP_TRAN (CMD12) shall be used to stop the transmission in Write Multiple Block whether the preerase (ACMD23) feature is used or not.
5.2.3. Responses
There are several types of response tokens. As in the SD Card mode, all are transmitted MSB first.
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SPI Protocol Definition
5.2.3.1. Format R1
This response token is sent by the card after every command with the exception of SEND_STATUS commands. It
is 1 byte long, the MSB is always set to zero and the other bits are error indications. A ‘1’ signals error.
•
•
•
•
•
•
•
In idle state—The card is in idle state and running initializing process.
Erase reset—An erase sequence was cleared before executing because an out of erase sequence
command was received.
Illegal command—An illegal command code was detected.
Communication CRC error—The CRC check of the last command failed.
Erase sequence error—An error in the sequence of erase commands occurred.
Address error—A misaligned address, which did not match the block length was used in the
command.
Parameter error—The command’s argument (e.g., address, block length) was out of the allowed range
for this card.
The structure of the R1 format is shown in Figure 5-7.
7
0
0
In Idle State
Erase Reset
Illegal Command
Com CRC Error
Erase_Seq_Error
Address Error
Parameter Error
Figure 5-7. R1 Response Format
5.2.3.2. Format R1b
This response token is identical to R1 format with the optional addition of the busy signal. The busy signal token
can be any number of bytes. A zero value indicates card is busy. A non-zero value indicates card is ready for the
next command.
5.2.3.3. Format R2
This 2-bytes long response token is sent by the card as a response to the SEND_STATUS command. The format of
the R2 status is shown in Figure 5-8.
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SPI Protocol Definition
7
Byte 1
0 7
Byte 2
0
0
Card is Locked
WP Erase Skip, Lock/Unlock Cmd Failed
Error
CC Error
Card ECC Failed
WP Violation
Erase Param
Out of Range, CSD_Overwrite
In Idle State
Erase Reset
Illegal Command
Com CRC Error
Erase Sequence Error
Address Error
Parameter Error
Figure 5-8. R2 Response Format
The first byte is identical to response R1. The content of the second byte is described below:
•
•
•
•
•
•
•
Erase param—An invalid selection, sectors for erase.
Write protect violation—The command tried to write a write-protected block.
Card ECC failed—Card internal ECC was applied but failed to correct the data.
CC error—Internal card controller error.
Error—A general or an unknown error occurred during the operation.
Write protect erase skip—Only partial address space was erased due to existing WP blocks.
Card is locked—Supported by the SanDisk SD Card.
5.2.3.4. Format R3
This response token is sent by the card when a READ_OCR command is received. The response length is 5 bytes.
The structure of the first (MSB) byte is identical to response type R1. The other four bytes contain the OCR register.
39
3231
0
0
R1
OCR
Figure 5-9. R3 Response Format
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SPI Protocol Definition
5.2.3.5. Data Response
Every data block written to the card is acknowledged by a data response token. It is one byte long and has the
following format:
7 6
x x x 0
0
Status
1
The meaning of the status bits is defined as follows:
•
•
•
‘010’—Data accepted.
‘101’—Data rejected due to a CRC error.
’110’—Data Rejected due to a Write Error
In case of any error (CRC or Write Error) during Write Multiple Block operation, the host shall stop the data
transmission using CMD12. In case of Write Error (response ’110’) the host may send CMD13 (SEND_STATUS)
in order to get the cause of the write problem. ACMD22 can be used to find the number of well written write
blocks.
5.2.4. Data Tokens
Read and write commands have data transfers associated with them. Data is being transmitted or received via data
tokens. All data bytes are transmitted MSB.
Data tokens are 4 to 515 bytes long and have the following format:
For Single Block Read, Single Block Write and Multiple Block Read:
•
First byte: Start Block.
7
0
1 1 1 1 1 1 1 0
•
•
Bytes 2-513 (depends on the data block length): User data.
Last two bytes: 16-bit CRC.
For Multiple Block Write operation:
•
First byte of each block.
If data is to be transferred then—Start Block
7
0
1 1 1 1 1 1 0 0
If Stop transmission is requested—Stop Tran
7
0
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5-15
SPI Protocol Definition
1 1 1 1 1 1 0 1
Note that this format is used only for Multiple Block Write. In case of Multiple Block Read the stop transmission is
done using STOP_TRAN Command (CMD12).
5.2.5. Data Error Token
If a read operation fails and the card cannot provide the required data it will send a data error token, instead. This
token is one byte long and has the format shown in Figure 5-10.
7
0
0
0
0
Error
CC Error
Card ECC Failed
Out of Range
Card is Locked
Figure 5-10. Data Error Token
The four least significant bits (LSB) are the same error bits as in response format R2.
5.2.6. Clearing Status Bits
As described in the previous paragraphs, in SPI mode, status bits are reported to the host in three different formats:
response R1, response R2 and data error token (the same bits may exist in multiple response types—e.g., Card ECC
failed). As in the SD mode, error bits are cleared when read by the host, regardless of the response format.
5.3. Card Registers
In SPI Mode, only the OCR, CSD and CID registers are accessible. Their format is identical to their format in the
SD Card mode. However, a few fields are irrelevant in SPI mode.
5.4. SPI Bus Timing Diagrams
All timing diagrams use the schematics and abbreviations listed in Table 5-5.
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SPI Protocol Definition
Table 5-4. SPI Bus Timing Abbreviations
H
Signal is high (logical ‘1’)
L
Signal is low (logical ‘0’)
X
Don’t care
Z
High impedance state (-> = 1)
*
Repeater
Busy
Busy Token
Command
Command token
Response
Response token
Data block
Data token
All timing values are defined in Table 5-5. The host must keep the clock running for at least NCR clock cycles after
the card response is received. This restriction applied to command and data response tokens.
5.4.1. Command/Response
Host Command to Card Response−Card is Ready
CS
H H L L L
*******************
<-NCS->
***************
DataIN X X H H H H 6 Bytes Command H H H H H
<-NCR->
1 or 2 Bytes Response
DataOut Z Z Z H H H H * * * * * * * * H H H H H
L L L L H H H
<-NEC->
H H H H X X X
H H H H H
Z
Z
Figure 5-11. Host Command to Card Response−Card is Ready
Host Command to Card Response−Card is Busy
The following timing diagram describes the command response transaction for commands when the card responses
which the R1b response type (e.g., SET_WRITE_PROT and ERASE). When the card is signaling busy, the host
may deselect it (by raising the CS) at any time. The card will release the DataOut line one clock after the CS going
high. To check if the card is still busy it needs to be reselected by asserting (set to low) the CS signal. The card will
resume busy signal (pulling DataOut low) one clock after the falling edge of CS.
CS
H L L L
*******************
L L L L H H H L L L L L L H H
<-NCS->
<-NEC->
<-NDS->
<-NEC->
DataIN X H H H H 6 Bytes Command H H H H H H H H H H H H H X X X H H H H H H X X
<-NCR->
Busy
L Z Z Z Busy H H H H Z
DataOut Z Z H H H H * * * * * * * * H H H H Card Response
Figure 5-12. Host Command to Card Response−Card is Busy
Card Response to Host Command
CS
DataIN
L L L L L
*******************
H H H H H H ************* H H H H
<-NCR->
H
H
H
H
H
1
or
2
Bytes
Response
H
H H H
DataOut
L
L H H H H
6 Bytes Command
H H H X X X X
*****************
H H H H Z Z Z
Figure 5-13. Card Response to Host Command
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
5-17
SPI Protocol Definition
5.4.2. Data Read
The following timing diagram describes all single block read operations with the exception of SEND_CSD
command.
CS
DataIN
H L L L
<-NCS->
X H H H H
****************************
Read Command
DataOut Z Z H H H H
L
L
L H H H H
<-NEC->
H H H X X X X
H H H H H
*************************
<-NCR->
<-NAC->
H H H H Card Response H H H H Data Block H H H H Z Z Z
********
Figure 5-14. Single Block Read Timing
The following table describes Stop transmission operation in case of Multiple Block Read.
CS
DataIN
L L L L
<- NCS ->
X H H H H
********************
Stop Tran command
Data Transfer to host
DataOut
H H H H H
* * * * ** * * *
<- NCR ->
H H Card Response H
<2clk>
Figure 5-15. Multiple Block Read Timing
Reading the CSD Register
The following timing diagram describes the SEND_CSD command bus transaction. The timeout values for the
response and the data block are NCR (Since the NAC is still unknown).
DataIN
H L L L
<- NCS ->
X H H H H
DataOut
Z Z H H H H
CS
*******************
Read Command
********
H H H H H
***************
<- NCR ->
<- NCR ->
H H H H Card Response H H H H Data Block
L L L H H H H
<- NEC ->
H H H X X X X
H H H H Z Z Z
Figure 5-16. Reading the CSD Register
5.4.3. Data Write
The host may deselect a card (by raising the CS) at any time during the card busy period (refer to the given timing
diagram). The card will release the DataOut line one clock after the CS going high. To check if the card is still busy
it needs to be re-selected by asserting (set to low) the CS signal.
The card will resume busy signal (pulling DataOut low) one clock after the falling edge of CS.
CS
H L
*******************
L L L L L L L L H H H L
<-NCS->
<-NWR->
<-NEC-> <-NDS->
H H H Data Block H H H H H H X X X H
DataIN X H H H Write Command H H H H
<-NCR->
L Z Z Z
DataOut Z Z H H H * * * * * * * * H H H Card Resp H H H H H H H Data Resp Busy
L
L
H H H
Busy
Figure 5-17. Device Write Timing
5-18
L
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
H
SPI Protocol Definition
The following figure describes stop transmission operation in Multiple Block Write transfer.
CS
Data In
L L L L L L L L L L L L L L L L L L L L L L H H H L L L L
<NWR -> <1byte-> <NBR -> <NEC -> <- NDS->
Data Block H H H H H H H H H stop tran H H H
X X X H H H H
token
Data Out
H H H H Data Resp Busy H H H H H H H H H Busy(1) L Z Z Z Busy(1) H
(1) The Busy may appear within NBR clocks after Stop Tran Token. If there is no Busy, the host may continue to the next
command.
Figure 5-18. Stop Transmission Timing—Multiple Block Write
5.4.4. Timing Values
Table 5-5 shows the timing values and definitions. For more information, refer to Table 4-17 in Section 4.0,
Section 5.1.9.2, and the applications note in Appendix A, “Host Design Considerations: NAND MMC and SDbased Products.”
Table 5-5. Timing Constants Definitions
Min
Max
Unit
NCS
0
-
8 Clock Cycles
NCR
0
8
8 Clock Cycles
NRC
1
-
8 Clock Cycles
NAC
1
See Note
8 Clock Cycles
NWR
1
-
8 Clock Cycles
NEC
0
-
8 Clock Cycles
NDS
0
-
8 Clock Cycles
NBR
0
1
8 Clock Cycles
NOTE: min [{{(TAAC ∗ f) + (NSAC ∗ 100)} ∗ 1/8}, {(100ms * f) * 1/8}] where units = (8 clocks) and “f” is the clock
frequency.
5.5. SPI Electrical Interface
The SPI Mode electrical interface is identical to that of the SD Card mode.
5.6. SPI Bus Operating Conditions
Identical to SD Card mode.
5.7. Bus Timing
Identical to SD Card mode. The timing of the CS signal is the same as any other card input.
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Appendix A. Application Note
Host Design Considerations: NAND MMC and SD-based Products
Introduction
SanDisk’s MultiMediaCard (MMC) and Secure Digital (SD) Card have been designed into a wide variety of
consumer electronic products: MP3 players, cell phones, PDAs, digital still and video cameras, data loggers, and
more. Although these cards were designed to support this wide range of products, there are many options an
engineer needs to consider before designing a card slot into a product. Design considerations include how the end
product handles timeout delays, bus type selection, block mode selection, and other options. These can have a
major impact on the performance and compatibility of the product. This Application Note will review these options
and provide recommendations on the optimum way to manage them.
Timing
There are important timing issues for the engineer to consider when designing products that integrate the
MultiMediaCard and/or SD Card.
Timing specifications
Design engineers must meet the rise, fall, setup, hold, and other SD Card and MultiMediaCard bus timing
specifications. If they want to support MultiMediaCards in their design, the clock speed should be controllable by
the host. This is due to the MultiMediaCard's open-drain mode; the MultiMediaCard powers up in the open-drain
mode and cannot handle a clock faster than 400 Khz. Once the MultiMediaCard completes the initialization
process, the card switches to the push-pull mode. In the push-pull mode the MultiMediaCard can run at the
maximum clock speed.
Refer to www.mmca.org and www.sdcard.org for timing specifications published by MultiMediaCard and
SD Card Associations.
Read access and program times
Read access and program times are also very critical to the proper operation of a product design. If the time-out
values for read access and program time are not met, data read from and written to the card may be incorrect or
invalid. MultiMediaCard and SD Card manufacturers have different read and write time-out values, and the
designer must ensure that the product time-out value is not set below the maximum specification.
The maximum read and write time-out values for the MultiMediaCard and SD Card are shown in Table 1.
Table 1.
MultiMediaCard and SD Card Maximum Read/Write Time-out Values
Product
MultiMediaCard
Time-out Values
Typical
Maximum
Read
(TAAC + NSAC)
10 * (TAAC + NSAC)
Write
(TAAC + NSAC) * R2W_FACTOR
(TAAC) + NSAC) * R2W_FACTOR * 10
SD Card
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
A-1
Application Note
Read
(TAAC + NSAC)
100ms
Write
(TAAC + NSAC) * R2W_FACTOR
250 ms
The factors used in calculating the values in Table 1—TAAC, NSAC, and R2W_FACTOR—can be read directly
from the CSD register of the MultiMediaCard and SD Card.
The TAAC factor’s unit is time, and the NSAC factor has units of 100 clocks. You can convert TAAC units to
clock cycles by multiplying by the frequency of the clock and calculate the time-outs in units of clock cycles if
desired. Alternatively, given the frequency of the clock, you can convert the NSAC units to time and calculate the
time-outs in units of time.
The R2W_FACTOR is a read-to-write factor and has no units. A design engineer can use the time-out values
derived from the CSD register to make the design compatible with all MultiMediaCards and SD cards regardless of
customer brand.
Interface
The MultiMediaCard and SD Card support multiple busses. Both cards support the 1-bit SPI bus that includes bus
pins DATin, DATout, CLK, and CS. The SPI bus is generally found on Motorola and other major MCU
manufacturer products.
The SD Card also supports a 4-bit and a 1-bit SD bi-directional bus mode. SD bus pins are CLK, CMD, and DAT
in 1-bit mode and CLK, CMD, and DAT[0:3] in 4-bit mode.
The MultiMediaCard also supports the 1-bit bi-directional MMC bus mode that has CLK, CMD, and DAT bus pins.
The CMD and DAT pins are bi-directional on the SD 1-bit, SD 4-bit, and MMC 1-bit.
The maximum burst rate achievable with the SD Card and MultiMediaCard depends on the clock speed and bus
mode. The burst rate is the data transfer rate between the card’s buffer and host.
Table 2.
MultiMediaCard and SD Card Clock Speed and Burst Rate
Product
Maximum Clock Speed and Burst Rate
MultiMediaCard
Clock Speed
Burst Rate
SPI Bus mode
20 MHz
2.5 MB/s
MMC 1-bit mode
20 MHz
2.5 MB/s
SPI Bus mode
25 MHz
3.125 MB/s
SD 1-bit mode
25 MHz
3.125 MB/s
SD 4-bit mode
25 MHz
12.5 MB/s
SD Card
The write and read throughput rates of the SD Card and MultiMediaCard are slower than the burst rate because each
card includes the busy time to write data from the card’s buffers to its internal Flash RAM, and busy time to read
data from the internal Flash RAM to the card’s buffer. Since most designs use this write and read busy time to
complete other processes, choosing a 1- or 4-bit bus mode can have a 4x speed effect on the time spent servicing the
SD Card.
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Ordering Information and Technical Support
The example in Table 3 shows the difference between moving 512 bytes of data to and from a MultiMediaCard or
SD Card internal buffer using different bus modes.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
A-3
Application Note
Table 3.
MultiMediaCard and SD Card Clock Speed and Transfer Time
Product
Maximum Clock Speed and Time Req. to move 512 bytes
MultiMediaCard
Clock Speed
Time
SPI Bus mode
20 MHz
204.8 us
MMC 1-bit mode
20 MHz
204.8 us
SPI Bus mode
25 MHz
163.8 us
SD 1-bit mode
25 MHz
163.8 us
SD 4-bit mode
25 MHz
41 us
SD Card
Read/Write Mode Selection
Another major MultiMediaCard and SD Card design consideration is the use of Singleblock or Multiblock
command modes. Singleblock mode reads and writes data one block at a time; Multiblock mode reads and writes
multiple blocks until a stop command is received.
Multiblock mode takes advantage of the multiple internal block buffers present in all MultiMediaCards or SD
Cards. In Multiblock mode, when one block buffer gets full during write, the card gives the host access to the other
empty block buffers to fill while programming the first block. The card does not enter a busy state until all block
buffers are full.
In Singleblock mode, the card enters a busy state by forcing the DAT line low when the first block buffer is full and
remains busy until the write process is complete. During the busy state, the host cannot send any additional data to
the card because the card forces the DAT line low.
If speed is critical in a design, Multiblock mode is the faster and recommended mode. The more blocks that can be
written in Multiblock mode the better the performance of the design. Therefore when planning the design, ensure
that enough system RAM is designed in to support the multiblock capability. The performance gain will always
outweigh the cost of the extra RAM. However, if speed is not critical—for example, a data-logger design that
records only 512 bytes of data every minute—Singleblock mode is more than adequate.
Power and Clock Control
Power control should be considered when creating designs using the MultiMediaCard and/or SD Card. The ability
to have software power control of the cards makes the design more flexible and robust. The host will have the
ability to turn power to the card on or off independent of whether the card is inserted or removed. This can help
with card initialization when there is contact bounce during card insertion. The host waits a specified time after the
card is inserted before powering up the card and starting the initialization process. Also, if the card goes into an
unknown state, the host can cycle the power and start the initialization process again. When card access is
unnecessary, allowing the host to power-down the bus can reduce overall power consumption.
Clock control is another option that should be implemented in a MultiMediaCard or SD Card design. As mentioned
in the Timing section, if the design needs to support the MultiMediaCard, the clock should be lowered to 400 kHz
or less during initialization. When the initialization process is complete, the host can raise the clock speed to the
card’s maximum.
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Ordering Information and Technical Support
Initialization Algorithm
The initialization algorithm needs to be considered for products designed to support the MultiMediaCard and SD
Card or SD Card only. An SD socket is physically thicker which allows both types of cards to be inserted.
Therefore, the host needs to be able to detect which card is inserted into the socket.
When the SD initialization command is used first, it causes the MultiMediaCard to return an error that provides the
host with an identification of the card type. If the host is supporting both the MultiMediaCard and SD Card, it can
continue the initialization using the MMC commands. If the host does not support both cards, it issues an error
message instructing the user to insert an SD Card.
If the design uses a MultiMediaCard socket, the host can start the initialization with the MMC command. The host
does not need to detect which type of card is inserted because the SD Card will not physically fit into an MMC
socket.
File System Support
If a design needs to support a file system, such as SanDisk’s Host Developers Tool Kit (HDTK), additional
considerations are necessary.
Reading and writing to an SD Card and MultiMediaCard is generally done in 512 byte blocks, however, erasing
often occurs in much larger blocks. The NAND architecture used by SanDisk and other card vendors currently has
Erase Block sizes of (32) or (64) 512 byte blocks, depending on card capacity. In order to re-write a single 512 byte
block, all other blocks belonging to the same Erase Block will be simultaneously erased and need to be rewritten.
For example—writing a file to a design using a FAT file system takes three writes/updates of the system area of
FAT and one write/update of the data area to complete the file write. First, the directory has to be updated with the
new file name. Second, the actual file is written to the data area. Third, the FAT table is updated with the file data
location. Finally, the directory is updated with the start location, length, date and time the file was modified.
Therefore, when selecting the file size to write into a design, the size should be as large as possible and a multiple of
the Erase Block size. This takes advantage of the architecture.
Some designs update the FAT table for every cluster of the data file written. This can slow the write performance,
because the FAT table is constantly being erased and re-written. The best approach is to write all the file clusters
then update the FAT table once to avoid the performance hit of erasing and re-writing all the blocks within the
Erase Block multiple times.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
A-5
Appendix B. Ordering Information
To order SanDisk products directly from SanDisk, call 408-542-0595.
Secure Digital Card
SDSDB-16
SDSDB-32
SDSDJ-64
SDSDJ-128
SDSDJ-256
SDSDJ-512
SDSDJ-1024
16 MB
32 MB
64 MB
128 MB
256 MB
512 MB
1024 MB
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
B-1
Appendix C. SanDisk Worldwide Sales Offices
To order SanDisk products directly from SanDisk, call 408-542-0595.
SanDisk Corporate
Headquarters
U.S. Retail Sales
140 Caspian Court
Sunnyvale, CA 94089
Tel: 408-542-0500
Fax: 408-542-0503
http://www.sandisk.com
Americas
10 Flagstone
Trabuco Canyon, CA 92679
Tel: 949-589-8351
Fax: 949-589-8364
U.S. Industrial/OEM Sales
Northwest USA
2241 Fremont Dr., Suite B
Havasu City, AZ 86406
Tel: 928-505-4258
Fax: 928-505-4259
Southwest USA & Mexico
140 Caspian Court
Sunnyvale, CA 94089
Tel: 408-542-0730
Fax: 408-542-0410
North Central USA &
South America
134 Cherry creek Circle, Suite 150
Winter Springs, FL 32708
Tel: 407-366-6490
Fax: 407-366-5945
Northeastern USA & Canada
620 Herndon Pkwy. Suite 200
Herndon, VA 22070
Tel: 703-481-9828
Fax: 703-437-9215
Retail Account Sales
32500 Mills Rd.
Avon, OH 44011
Tel: 440-327-0490
Fax: 440-327-0295
International Retail Sales
European Retail Sales
Wilhelminastraat 10
2011 VM Haarlem
The Netherlands
Tel: 31-23-5514226
Fax: 31-23-5348625
Southern European Retail Sales
Centre Hoche Condorcet
3 Rue Condorcet—B.P. 9
91263 Juvisy Sur Orge Cedex
France
Tel: 33-169-12-16-04
Fax: 33-169-12-16-24
Japan Retail Sales
Umeda-Shinmichi Bldg. 10F
1-1-5 Dojima, Kita-ku
Osaka 530-0003
Tel: 81-6-6343-6480
Fax: 81-6-6343-6481
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
International
Industrial/OEM Sales
Europe
SanDisk GmbH
Karlsruher Str. 2C
D-30519 Hannover, Germany
Tel: 49-511-875-9131
Fax: 49-511-875-9187
Northern Europe
Videroegatan 3 B
S-16440 Kista, Sweden
Tel: 46-08-75084-63
Fax: 46-08-75084-26
Central and Southern
Europe
Rudolf-Diesel-Str. 3
40822 Mettmann, Germany
Tel: 49-210-495-3433
Fax: 49-210-495-3434
Japan
8F Nisso Bldg. 15
2-17-19 Shin-Yokohama,
Kohoku-ku
Yokohama 222-0033,
Japan
Tel: 81-45-474-0181
Fax: 81-45-474-0371
Asia/Pacific Rim
89 Queensway, Lippo Center
Tower I, Suite 3402
Admiralty, Hong Kong
Tel: 852-2712-0501
Fax: 852-2712-9385
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SanDisk Worldwide Sales Offices
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Appendix D. Limited Warranty
I. WARRANTY STATEMENT
SanDisk warrants its products to be free of any defects in materials or workmanship that would prevent them from functioning
properly for one year from the date of purchase. This express warranty is extended by SanDisk Corporation to its customers.
II. GENERAL PROVISIONS
This warranty sets forth the full extent of SanDisk’s responsibilities regarding the SanDisk Secure Digital Card. In satisfaction of
its obligations hereunder, SanDisk, at its sole option, will either repair, replace or refund the purchase price of the product.
NOTWITHSTANDING ANYTHING ELSE IN THIS LIMITED WARRANTY OR OTHERWISE, THE EXPRESS
WARRANTIES AND OBLIGATIONS OF SELLER AS SET FORTH IN THIS LIMITED WARRANTY, ARE IN LIEU OF,
AND BUYER EXPRESSLY WAIVES ALL OTHER OBLIGATIONS, GUARANTIES AND WARRANTIES OF ANY KIND,
WHETHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION, ANY IMPLIED WARRANTY OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR INFRINGEMENT, TOGETHER WITH ANY
LIABILITY OF SELLER UNDER ANY CONTRACT, NEGLIGENCE, STRICT LIABILITY OR OTHER LEGAL OR
EQUITABLE THEORY FOR LOSS OF USE, REVENUE, OR PROFIT OR OTHER INCIDENTAL OR CONSEQUENTIAL
DAMAGES, INCLUDING WITHOUT LIMITATION PHYSICAL INJURY OR DEATH, PROPERTY DAMAGE, LOST
DATA, OR COSTS OF PROCUREMENT OF SUBSTITUTE GOODS, TECHNOLOGY OR SERVICES. IN NO EVENT
SHALL THE SELLER BE LIABLE FOR DAMAGES IN EXCESS OF THE PURCHASE PRICE OF THE PRODUCT,
ARISING OUT OF THE USE OR INABILITY TO USE SUCH PRODUCT, TO THE FULL EXTENT SUCH MAY BE
DISCLAIMED BY LAW.
SanDisk’s products are not warranted to operate without failure.
III. WHAT THIS WARRANTY COVERS
For products found to be defective within one year of purchase, SanDisk will have the option of repairing or replacing the
defective product, if the following conditions are met:
A. The defective product is returned to SanDisk for failure analysis as soon as possible after the failure occurs.
B. An incident card filled out by the user, explaining the conditions of usage and the nature of the failure,
accompanies each returned defective product.
C. No evidence is found of abuse or operation of products not in accordance with the published specifications, or
of exceeding storage or maximum ratings or operating conditions.
All failing products returned to SanDisk under the provisions of this limited warranty shall be tested to the product’s functional
and performance specifications. Upon confirmation of failure, each product will be analyzed, by whatever means necessary, to
determine the root cause of failure. If the root cause of failure is found to be not covered by the above provisions, then the
product will be returned to the customer with a report indicating why the failure was not covered under the warranty.
This warranty does not cover defects, malfunctions, performance failures or damages to the unit resulting from use in other than
its normal and customary manner, misuse, accident or neglect; or improper alterations or repairs.
SanDisk reserves the right to repair or replace, at its discretion, any product returned by its customers, even if such product is not
covered under warranty, but is under no obligation to do so.
SanDisk may, at its discretion, ship repaired or rebuilt products identified in the same way as new products, provided such cards
meet or exceed the same published specifications as new products. Concurrently, SanDisk also reserves the right to market any
products, whether new, repaired, or rebuilt, under different specifications and product designations if such products do not meet
the original product’s specifications.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
D-1
Limited Warranty
IV. RECEIVING WARRANTY SERVICE
According to SanDisk’s warranty procedure, defective product should be returned only with prior authorization from SanDisk
Corporation. Please contact SanDisk’s Customer Service department at 408-542-0595 with the following information: product
model number and description, nature of defect, conditions of use, proof of purchase and purchase date. If approved, SanDisk
will issue a Return Material Authorization or Product Repair Authorization number. Ship the defective product to:
SanDisk Corporation
Attn: RMA Returns
(Reference RMA or PRA #)
140 Caspian Court
Sunnyvale, CA 94089
V. STATE LAW RIGHTS
SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL
DAMAGES, OR LIMITATION ON HOW LONG AN IMPLIED WARRANTY LASTS, SO THE ABOVE LIMITATIONS OR
EXCLUSIONS MAY NOT APPLY TO YOU. This warranty gives you specific rights and you may also have other rights that
vary from state to state.
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SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Appendix E. Disclaimer of Liability
SanDisk Corporation general policy does not recommend the use of its products in life support applications wherein
a failure or malfunction of the product may directly threaten life or injury. Accordingly, in any use of products in
life support systems or other applications where failure could cause damage, injury or loss of life, the products
should only be incorporated in systems designed with appropriate redundancy, fault tolerant or back-up features.
SanDisk shall not be liable for any loss, injury or damage caused by use of the Products in any of the following
applications:
−
Special applications such as military-related equipment, nuclear reactor control, and aerospace
−
Control devices for automotive vehicles, train, ship and traffic equipment
−
Safety system for disaster prevention and crime prevention
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Medical-related equipment including medical measurement device
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
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