So I'm getting a "prefetch abort" exception on our arm9 system. This system does not have an MMU, so is there anyway this could be a software problem? All the registers seem correct to me, and the code looks right (not corrupted) from the JTAG point of view.
Right now I'm thinking this is some kind of hardware issue (although I hate to say it - the hardware has been fine until now).
What exactly is the exception you're getting?
Last time this happened to me, I went up the wrong creek for a while because I didn't realize an ARM "prefetch abort" meant the instruction prefetch, not data prefetch, and I'd just been playing with data prefetch instructions. It simply means that the program has attempted to jump to a memory location that doesn't exist. (The actual problem was that I'd mistyped "go 81000000" as "go 81000" in the bootloader.)
See also:
What's the address that the prefetch abort is triggering on. It can occur because the program counter (PC or R15) is being set to an address that isn't valid on your microcontroller (this can happen even if you're not using an MMU - the microcontroller's address space likely has 'holes' in it that will trigger the prefetch abort). It could also occur if you try to prefetch an address that would be improperly aligned, but I think this dpends on the microcontroller implementation (the ARM ARM lists the behavior as 'UPREDICTABLE').
Is the CPU actually in Abort mode? If it's executing the Prefetch handler but isn't in abort mode that would mean that some code is branching through the prefetch abort vector, generally through address 0x0000000c but controllers often allow the vector addresses to be remapped.