User manual

ZEUS user manual
Issue E
36
Expansion interfaces
There are three expansion interfaces on the ZEUS: SDIO, PC/104 and CompactFlash.
PC/104 and CompactFlash interfaces are connected to the PC card memory controller of
the PXA270 with the use of some ‘glue logic’ implemented in a CPLD (Xilinx XC9536XL).
There is a CPLD Firmware version/issue register that can be accessed at the address
0x12000000.
CPLD ver/issue register [REG0]
Byte lane Most significant byte Least significant byte
Bit
15 14 13 12 11 10 9 8 [7:4] [3:0]
Field - - - - - - - - VER[3:0] ISSUE[3:0]
Reset X X X X X X X X Current Version Current Issue
R/W - - - - - - - - Read Only
Address 0x12000000
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
.