Debugging NIOS code in hardware while TIMER is running.

Welcome to the world of device driver debugging.

Basically the world doesn't stop to let you breakpoint/single step code.

General techniques:

1) printf - but that is often too slow and you generate too much data for any uart.

2) Allocate a trace array and write info to it. If you make each entry 16 bytes it will hexdump nicely, write a value that happens to be a 4 character string to the first entry to make them easier to identify.

3) Use a hardware monitor to trace all the bus cycles. You can use signaltap for this, but finding the correct nodes is 'interesting'. We monitored the accesses to the (tightly coupled) m9K memory blocks. I don't know if you can tap the address/data interface to the instruction and data caches.