[U-Boot-Users] BDI2000 and MPC8260
Jerry Van Baren
gerald.vanbaren at smiths-aerospace.com
Tue Sep 6 21:48:57 CEST 2005
Wolfgang Denk wrote:
> In message <431DB954.9030803 at smiths-aerospace.com> you wrote:
>
>>* Freescale seems to have stopped providing unfettered access to the
>>BSDL (Boundary Scan Description Language) interface to their processors.
>> For instance, the MPC8260 is not in the list:
>><http://www.freescale.com/webapp/sps/site/overview.jsp?nodeId=0162468rH3bTdGZj9NtRjM>
>
> We were never able to pass their NDA roadblocks when we asked for the
> necessary information to extend the BDM4GDB adapter for 82xx... :-(
Slightly different question, different answer ;-). The BSDL is
describing the processor I/O ring shift register, allowing the JTAG to
wiggle pins. What you are referring to is the COP (?) debugger
interface which is also accessed via JTAG but is proprietary. The BSDL
_is_ available as Rune pointed out. This allows you to program memory
(very slowly) by shifting an {address, data, chip select}, toggle the
write line, repeat ad nausium.
Note that you have to be careful with wiggling pins via JTAG: if you
inadvertantly set two pins that are connected together to be "output"
and set them to fighting, one of them will lose (generally the
processor). I would never do that, but know someone who did ;-).
[snip]
> Best regards,
> Wolfgang Denk
Thanks,
gvb
More information about the U-Boot
mailing list