Secure Digital I/O Card Pinout

Secure Digital I/O Card Description

Secure Digital Input/Output [SDIO] is a flash based removable memory card. The card format may also be used for other device functions in addition to data storage. Secure Digital IO uses a 9-Pin connector [1 row of 9 pins]. SDIO is based on the Secure Digital SD card. SDIO is compatible with the SD memory card, and fits in the same socket.

SDIO Card pin locations and Secure Digital IO card drawing

The Secure Digital I/O card dimensions are: 24mm wide x 32mm long x 2.1mm thick.

There are two types of SDIO cards; a full-speed version, and a slow-speed version. The full-speed version will operate with a 1-bit and 4-bit SD transfer mode, both with a clock ranging from 0Hz to 25MHz. The 4-bit version operating at 25MHz has a transfer rate of 100Mbps. The slow-speed version will use the 1-bit mode and may have the 4-bit mode, but only operates at a transfer rate of between 0Hz and 400kHz. The slow-speed version is not intended for memory functions. The SDIO card support the SPI bus interface. The SDIO mechanical form factor is shown above; however a few gaps "lock notches" are not shown. The SDIO card may exceed 24mm in width after 37mm in length, and the width may be thicker then 2.1mm after 37mm in length.

Secure Digital I/O Card, Pin Out

Secure Digital I/O Pinout
Pin #
SD 4-bit Mode
SD 1-bit Mode
SPI Mode
1 CD/DAT[3] Data Line 3 N/C Not Used CS Card Select
2 CMD Command Line CMD Command Line DI Data Input
3 VSS1 Ground VSS1 Ground VSS1 Ground
4 VDD Supply Voltage VDD Supply Voltage VDD Supply Voltage
5 CLK Clock CLK Clock SCLK Clock
6 Vss2 Ground Vss2 Ground Vss2 Ground
7 DAT[0] Data Line 0 DATA Data Line DO Data Output
8 DAT[1] Data Line 1 / Interrupt IRQ Interrupt IRQ Interrupt
9 DAT[2] Data Line 2 /Read Wait RW Read Wait NC Not Used

The graphic below provides a comparison of the different removable memory card standards. Many of the different Memory Card standards have descriptions listed on this web site. The different standards based on card size are provided.
Refer to the Personal Computer Buses page for more information for different memory types, as listed here.

Different Flash Memory Stick Formats.

Comparison of Removable Memory Card sizes

The SD card, 32mm x 24mm
The miniSD card, 21.5 x 20mm
The microSD card, 15mm x 11mm
Slot adaptors may be purchased to allow a smaller SD
card type to plug into a larger type.

Arasan Chip Systems {SDIO Card Controller IC}

The MicroSD form factors picture is used under GNU License

SD Card Connector Manufacturers

This is a listing of OEM SD connector manufacturers.
In most cases the connector is a surface mount [SM] component;
mounting to the Printed Wiring Board [PWB] via SMT.

{shielded and unshielded SD card connectors,
Also Top Mount, Bottom Mount, Reverse Mount}

Tyco Electronics
{Standard Secure Digital SMD connector, top & bottom mount}

Wieson Technologies Co., Ltd. {SD P/P Internal Type}

Yamaichi Electronics {Secure Digital connector}

Comparison of SD Memory Card sizes
Comparison of SD Memory Card sizes
SD Card, miniSD Card, microSD Card

{Secure Digital IO Card Index}

PC motherboard

Distributor rolodex Electronic Components Electronic Equipment EDA CDROM Software Engineering Standards, BOB card Cabled Computer Bus Electronic Engineering Design Table Conversion DB9-to-DB25.
DistributorsComponents Equipment Software Standards Buses Design Reference

Modified 1/2/12
Copyright © 1998 - 2016 All rights reserved Larry Davis