[LinuxBIOS] In System Flash Programming [Was: BIOS Saver RD1]

Jeff Carr jcarr at linuxmachines.com
Tue Aug 16 02:04:23 CEST 2005

On 08/15/2005 01:59 PM, Ken Fuchs wrote:
> YH wrote:
>>The xeltek ISP Header + 280U can be used for in-system programming.
>>That could be useful, if your mb don't have flash socket and flash os
>>soldered in.

That's great; I just added it to the FAQ. The hardware development tools
links currently in the FAQ might be better off right on the main page.
Anyone seriously interested in helping linuxbios is going to need some
of those tools.

> This would require one or more (a lot of them for the Xeltek ISP
> Header) headers on the mainboard.  I couldn't find any information
> about the Xeltek ISP Header.  It seems like it might even work on an
> Enhanced Willem Universal Programmer.  It would be simpler to have a
> single larger header, if the Xeltec ISP Header (adapter) needs to be
> detached while the mainboard is operating.  I'd really prefer
> something that can remain attached while the mainboard is in
> operation.

Ya, there are such things floating around. I've seen in circuit
programmers before; this xeltek one looks like it may be hard to use.

> It would even be possible to use the JTAG connector to flash the
> system BIOS.  All Opteron mainboards must include "JTAG" circuits, but

You don't say!

> usually don't include the two JTAG headers.  Adding the headers is
> quite easy.  

Hmmm. two headers? Interesting.

> An open source Opteron JTAG flash programmer is probably
> won't happen any time soon, 

Holy (**& that's fantastic. It sure might happen soon! OK, I might be
getting ahead of myself. Are you sure the Opteron doesn't require a ITP
or similar debugging port? Or in other words: Can you single step/halt
the processor/dump registers using the JTAG port. Lets hope so;
otherwise you might not be able to do much via the JTAG port.

JTAG is a fantastic standard -- I'd expect it to be adopted for any new
chip entering the market.

> although it shouldn't be too difficult to
> do.  Anyone aware of an open source JTAG flash programmer of any kind?

Yes, there are at least two projects. I added a JTAG programming page to
the FAQ: http://linuxbios.org/index.php/JTAG/BSDL_Guide

So here are some questions then:

Do you know of any motherboards that leave the JTAG connections populated?

Do you have instructions for populating them on some motherboard I could
pick up?

Do you have links to the Opteron JTAG docs (these docs will tell you
what you can and can't do from the JTAG port)?

We will need the BSDL files for the Opteron. Now if only that was the
case for the Pentium M...

Have a nice day,

Here is output of talking to a Xilinx FPGA & CPLD using a $25 jtag cable
from linux with all free software: (that's why everyone is switching to
JTAG -- cheaper manufacturing software/hardware costs)

jtag> cable parallel 0x378 DLC5
Initializing Xilinx DLC5 JTAG Parallel Cable III on parallel port at 0x378
jtag> detect
IR length: 14
Chain length: 2
Device Id: 00000101000001000110000010010011
  Manufacturer: Xilinx
  Unknown part!
Device Id: 00010001010000101000000010010011
  Manufacturer: Xilinx
  Part:         xc3s1000_ft256
  Stepping:     0
  Filename:     /usr/share/jtag/xilinx/xc3s1000_ft256/xc3s1000_ft256
chain.c(110) Part 0 without active instruction
chain.c(133) Part 0 without active instruction
chain.c(110) Part 0 without active instruction
jtag> instruction SAMPLE/PRELOAD
jtag> shift ir
chain.c(110) Part 0 without active instruction

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