©Copyright 2000-2007 SD Card Association

SDIO Simplified Specification Version 2.00

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

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SDI Technologies SDIO Card manual Table of Contents