[flashrom] ft2232: TI Stellaris DevKit / Dediprog SF100 IF / SPI Chip

[Philipp Wiesner]

Hi

I had to flash a BIOS chip via SPI.
The board i was flashing was the mainboard of a 'iEi TANK-800-D525'
computer (it's a rugged industrial sff computer). I don't have access to
the machine ATM so I can't tell what the exact name of the board is, but
it's a custom mainboard only used in this computer AFAIK. It has a
SST25VF016B BIOS-chip (which is well supported) and an interface designed
for the Dediprog SF100 programmer, which essentially is a SPI interface
with an optional IO line. (Documentation is available online, for users as
well as for hardware developers, so the interface is well documented).

The programmer I used was a Texas Instruments DK-LM3S9B96 Stellaris
development kit. It has a JTAG-Interface, which is externally accessable
via pin header. The interface is provided by a FTDI ft2232 chip together
with some glue logic (essentially bus buffers, some logic). I had to make
some customizations to ft2232.c add support for this programmer. I had to
build a cable which connects the JTAG interface with the on-board SF100
interface.

Needless to say, I was successful.

I like to share as much of the knowledge I acquired as possible with the
community. The least thing I can do is send a patch with my modifications
for the TI development board. I still need to read the instructions on how
to prepare and send patches as I haven't done this in a long time.

IMHO other TI Stellaris development boards share the same JTAG interface
concept, but I can't name them. If someone has suggestions, I could check
those boards for compatibility (by schematics). BTW, vid=0x0403 (FTDI
default), pid=0xbcd9. In fact, a lot of USB-JTAG-Interfaces on development
boards should be capable of doing this.

The board needs to be flashed while completely off. At least I was not
successful using the optional IO-line to claim exclusive access to the chip
while in standby/running.

I'm going to send a follow-up if I have specific questions. In the meantime
you can ask questions if you think anything I did can be useful for you /
for everyone.

Kind regards,
P. Wiesner