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