Compaq Extension manual Alternative Gpio use for Sdio Interface, Sdio Pin description

5 Hardware extensions

5.2.1Alternative GPIO use for SDIO Interface

Pin A54 A63 A67 A85 A93

GPIO SDIO Pin GPIO SDIO GPI0 DATA0 B54 GPO1 CMD GPI1 DATA1 B57 GPO2 WP GPI2 DATA2 B63 GPO3 CD# GPI3 DATA3

GPO0 CLK

SDIO Pin description

Signal	Type	Description
SD_DATA[3:0]	I/O	SDIO Controller 0/1/2 Data: These signals operate
	CMOS3.3	in push-pull mode. The SD card includes internal pull-
		up resistors for all data lines. By default, after power-
		up, only SDn_DATA0 is used for data transfer. Wider
		data bus widths can be configured for data transfer.
SD_CMD	I/O	SDIO Controller 0/1/2 Command: This signal is
	CMOS3.3	used for card initialization and transfer of commands.
		It has two operating modes: open-drain for
		initialization mode, and push-pull for fast command
		transfer.
SD1_CLK	O	SDIO Controller 0/1/2 Clock: With each cycle of this
	CMOS3.3	signal a one-bit ransfer on the command and each
		data line occurs.
		This signal is generated by Intel SCH at a maximum
		frequency of:
		24 Mhz for SD and SDIO.
		48 Mhz for MMC.
SD0_WP	I	SDIO Controller 0/1/2 Write Protect: These signals
	CMOS3.3	denote the state of the write-protect tab on SD cards.
SD1_CD#	I	SDIO Controller 0/1/2 Card Detect: Indicates when
	CMOS3.3	a card is present in an external slot.

Copyright © COM Express™ Extension

17

Specification Rev 013