Re: Debugging MIPS cpu with a probe, how?

[Johannes Stezenbach <js@linuxtv.org>]

On Tue, Aug 05, 2008, TriKri wrote:
> 
> I have an embedded system, a box, with a MIPS processor on it, which I need
> to debug (stop and start the processor, tell what instructions it has
> previously executed, etc.). I also have an EJTAG probe, which I have
> connected between the computer's usb and the box, and written software for
> it. The software can communicate with the probe, which in its own turn can
> communicate with the box through the tap (test access port), by giving the
> tap certain instructions. It can also, through the tap, feed the MIPS
> processor with instructions, and read/write data from processor registers.
> 
> The question is now, how can debug the processor? How do I stop it, do I
> have to send any certain instructions to it? How can I set a breakpoint
> (which I understand is a quite crucial point)? Can I use GDB with my
> software to help debug the processor and how do I do that?

I looked for Open Source EJTAG software a while ago and found
two projects which may be of interest to you:

http://svn.berlios.de/svnroot/repos/openocd/branches/mips/
http://www.totalembedded.com/open_source/jtag/mips32_ejtag/

But I didn't try to use any of it so far.


Johannes