View of device with cover and PCMCIA card removed
The box can be dismantled relatively easily by unclipping the top cover. The PCMCIA wireless network card can then be slid out of the bracket to allow access to the circuit below.
View of device with cover and PCMCIA card removed
This is an Intel PXA255 processor with many interesting peripherals integrated, although many of them are unused. It is impossible to access the pins on this chip because of the mBGA packaging. The developers manual is an invaluable source of information, especially if you are planning to create a bootloader for this device.
16MB of SDRAM is available at physical address 0xa0000000. This is provided by two IC42S16400 devices connected in parallel to form a 32bit data bus. They use memory partition 0.
2MB non volatile flash memory is used to hold the bootloader, kernel and initial ramdisk. It is connected to CS0 at physical address 0x00000000. This memory can be reprogrammed using a JTAG connector and JFlashMM (details).
The device has stereo audio output from a Sigmatel STAC9750 AC97 audio IC. This works in combination with the AC97 support in the processor. No SPDIF output is present in the WMA11b but the datasheet for this device shows it is possible to enable SPDIF output on pin 48 by pulling this pin low with a 1K-10K resistor. I added such a resistor but found there was still no output. I expect it needs to be enabled/configured in software (see the Extended Audio Control/Status register at 0x2A). The reference design below shows how an optical or coax digital output should be connected.
STAC9750 datasheet | STAC9750 reference design
Three LEDs are mounted on the front panel, labelled Power, Wireless and Ethernet. These are connected to some of the processors GPIO pins. Logic high turns the LEDs on, logic low turns them off. LED4 is unpopulated in this device but it is a simple task to fit one should it be required.
| LED | Label | GPIO pin |
|---|---|---|
| LED1 | Wireless | 0 |
| LED2 | Ethernet | 3 |
| LED3 | Ready | 5 |
| LED4 | 8 |
Ethernet is provided by an integrated MAC & PHY in the form of a Davicom DM9000 with an ISA style interface to the processor.
802.11b wireless using a prism chipset PCMCIA adapter.
Output to the TV is from a Focus TV-FS450 IC.
FS450 datasheet
Thanks to James Pitts for helping me find this
By
Andrew Wild
|
Visitor Statistics
|
Portugal Holiday
This file last modified
04/11/2005 10:03pm