Hi, a couple of weeks ago i bought a handheld gaming console containing a MMSP2 SoC. I have been playing around a little with JTAG and thought it could be fun to learn more about dual core debugging, but i have encountered some strange behaviour.
The MMSP2 chip contains 1x arm920 and 1x arm940 core, and the 920 is the 'main' CPU.
When i check the length of the IR it's always 4 bits long, so i assume there are no daisy chained TAP controllers there, and the IDCODE always say it's a 920.
Just playing around with the 920 works fine, but when i enable the clock to the 940 strange things begin to happen. It seems like all instructions i push into SC1 is also pushed into the
940 core, but the IR register length is still 4, and IDCODE still say 920.This is a problem ofcourse because when i want to continue execution, and i load the PC address and restart the core, both cores will start at the same address.
Is this a normal behaviour and is there a way to handle it? And, do anyone have any experience of the MMSP2 and could shed some light on this?
-- regards Bjorn