SD Specifications
Part E1
SDIO Simplified Specification
Version 2.00
February 8, 2007
Technical Committee
SD Card Association
©Copyright 2000-2007 SD Card Association
SDIO Simplified Specification Version 2.00
i
Revision History
Date Version Changes compared to previous issue
April 3, 2006 1.10 Simplified Version Initial Release
February 8, 2007 2.00 (1) Added method to change bus speed (Normal Speed up to 25MHz
and High Speed up to 50 MHz)
(2) Operational Voltage Requirement is extended to 2.7-3.6V
(3) Combine sections 12 (Physical Properties) and 13 (Mechanical
Extensions) and add miniSDIO to the new section 13 (Physical
Properties)
(4) Add Embedded SDIO ATA Standard Function Interface Code
(5) Reference of Physical Ver2.00 supports SDHC combo card.
(6) Some typos in Ver1.10 are fixed.
©Copyright 2000-2007 SD Card Association
SDIO Simplified Specification Version 2.00
ii
Release of SD Simplified Specification
The following conditions apply to the release of the SD simplified specification ("Simplified Specification") by
the SD Card Association. The Simplified Specification is a subset of the complete SD Specification which is
owned by the SD Card Association.
Publisher:
SD Association
2400 Camino Ramon, Suite 375
San Ramon, CA 94583 USA
Telephone: +1 (925) 275-6615
Fax: +1 (925) 886-4870
E-mail: office@sdcard.org
Copyright Holder:
The SD Card Association
Notes:
This Simplified Specification is provided on a non-confidential basis subject to the disclaimers below. Any
implementation of the Simplified Specification may require a license from the SD Card Association or other
third parties.
Disclaimers:
The information contained in the Simplified Specification is presented only as a standard specification for SD
Cards and SD Host/Ancillary products and is provided "AS-IS" without any representations or warranties of
any kind. No responsibility is assumed by the SD Card Association for any damages, any infringements of
patents or other right of the SD Card Association or any third parties, which may result from its use. No
license is granted by implication, estoppel or otherwise under any patent or other rights of the SD Card
Association or any third party. Nothing herein shall be construed as an obligation by the SD Card
Association to disclose or distribute any technical information, know-how or other confidential information to
any third party.
©Copyright 2000-2007 SD Card Association
SDIO Simplified Specification Version 2.00
iii
Conventions Used in This Document
Naming Conventions
Some terms are capitalized to distinguish their definition from their common English meaning. Words not
capitalized have their common English meaning.
Numbers and Number Bases
Hexadecimal numbers are written with a lower case “h” suffix, e.g., FFFFh and 80h.
Binary numbers are written with a lower case “b” suffix (e.g., 10b).
Binary numbers larger than four digits are written with a space dividing each group of four digits, as in 1000 0101
0010b.
All other numbers are decimal.
Key Words
May: Indicates flexibility of choice with no implied recommendation or requirement.
Shall: Indicates a mandatory requirement. Designers shall implement such mandatory requirements to
ensure interchangeability and to claim conformance with the specification.
Should: Indicates a strong recommendation but not a mandatory requirement. Designers should give strong
consideration to such recommendations, but there is still a choice in implementation.
Application Notes
Some sections of this document provide guidance to the host implementers as follows:
Application Note:
This is an example of an application note.
©Copyright 2000-2007 SD Card Association
SDIO Simplified Specification Version 2.00
iv
Table of Contents
1. General Description ................................................................................................................................. 1
1.1 SDIO Features .................................................................................................................................... 1
1.2 Primary Reference Document ............................................................................................................. 1
1.3 Standard SDIO Functions.................................................................................................................... 1
2. SDIO Signaling Definition........................................................................................................................ 2
2.1 SDIO Card Types ................................................................................................................................ 2
2.2 SDIO Card modes............................................................................................................................... 2
2.2.1 SPI (Card mandatory support) ..................................................................................................... 2
2.2.2 1-bit SD Data Transfer Mode (Card Mandatory Support) ............................................................. 2
2.2.3 4-bit SD Data Transfer Mode (Mandatory for High-Speed Cards, Optional for Low-Speed)......... 2
2.3 SDIO Host Modes ............................................................................................................................... 2
2.4 Signal Pins .......................................................................................................................................... 3
3. SDIO Card Initialization............................................................................................................................ 4
3.1 Differences in I/O card Initialization ..................................................................................................... 4
3.2 The IO_SEND_OP_COND Command (CMD5)................................................................................. 10
3.3 The IO_SEND_OP_COND Response (R4)........................................................................................11
3.4 Special Initialization considerations for Combo Cards....................................................................... 12
3.4.1 Re-initialize both I/O and Memory .............................................................................................. 12
3.4.2 Using a Combo Card as SDIO only or SD Memory only after Combo Initialization.................... 12
3.4.3 Acceptable Commands after Initialization .................................................................................. 12
3.4.4 Recommendations for RCA after Reset ..................................................................................... 12
3.4.5 Enabling CRC in SPI Combo Card............................................................................................. 14
4. Differences with SD Memory Specification.......................................................................................... 15
4.1 SDIO Command List ......................................................................................................................... 15
4.2 Unsupported SD Memory Commands............................................................................................... 15
4.3 Modified R6 Response ...................................................................................................................... 16
4.4 Reset for SDIO.................................................................................................................................. 16
4.5 Bus Width.......................................................................................................................................... 16
4.6 Card Detect Resistor......................................................................................................................... 17
4.7 Timings.............................................................................................................................................. 17
4.8 Data Transfer Block Sizes ................................................................................................................. 18
4.9 Data Transfer Abort ............................................................................................................
............... 18
4.9.1 Read Abort ................................................................................................................................. 18
4.9.2 Write Abort ................................................................................................................................. 18
4.10 Changes to SD Memory Fixed Registers .......................................................................................... 18
4.10.1 OCR Register............................................................................................................................. 19
4.10.2 CID Register............................................................................................................................... 19
4.10.3 CSD Register ............................................................................................................................. 19
4.10.4 RCA Register ............................................................................................................................. 19
4.10.5 DSR Register ............................................................................................................................. 19
4.10.6 SCR Register ............................................................................................................................. 19
4.10.7 SD Status ................................................................................................................................... 19
4.10.8 Card Status Register .................................................................................................................. 19
5. New I/O Read/Write Commands............................................................................................................ 21
5.1 IO_RW_DIRECT Command (CMD52) .............................................................................................. 21
5.2 IO_RW_DIRECT Response (R5) ......................................................................................................22
5.2.1 CMD52 Response (SD modes).................................................................................................. 22
5.2.2 R5, IO_RW_DIRECT Response (SPI mode) ............................................................................. 23
5.3 IO_RW_EXTENDED Command (CMD53) ........................................................................................ 24
5.3.1 CMD53 Data Transfer Format .................................................................................................... 25