Secure Digital I/O, SD Card

 

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.

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