ZEUS Technical Manual

Detailed hardware description

 

 

SDIO

The SD card socket J22 is interfaced directly to PXA270’s MMC/SD/SDIO controller.

The MMC/SD/SDIO controller supports multimedia card, secure digital and secure digital I/O communications protocols. The MMC controller supports the MMC system, a low cost data storage and communications system. The MMC controller in the PXA270 processor is based on the standards outlined in the MultiMediaCard System Specification Version 3.2. The SD controller supports one SD or SDIO card based on the standards outlined in the SD Memory Card Specification Version 1.01 and SDIO

Card Specification Version 1.0 (Draft 4).

The MMC/SD/SDIO controller features:

•Data transfer rates up to 19.5Mbit/s for MMC, 1-bit SD and SPI mode data transfers, and up to 9.75Mbit/s for 1-bit SDIO.

•Data transfer rates up to 78Mbit/s for 4-bit SD data transfers, and up to 39Mbit/s for SDIO.

•Support for all valid MMC and SD/SDIO protocol data transfer modes.

This is a hot swappable 3.3V interface, controlled by the detection of a falling edge on GPIO53 when an SD card has been inserted, and a rising edge when an SD card is removed.

SD card write protection is connected to PXA270’s GPIO52, and card detect to GPIO53.

A variety of SDIO cards are available, such as a Bluetooth and IEEE802.11b (WiFi). More information can be found here: www.sdcard.org/sdio.

© 2007 Eurotech Ltd Issue D

39