AVR-Chat

>
>Its the kind of thing that could be hard to track down. I don't know
>of a way for a routine to extract the vector which called it. Write
>such a routine and substitute for the default. Otherwise one is stuck
>writing a unique IRQ service routine for each and every IRQ vector.
>Do something unique in each routine and you'll know which is getting
>dispatched.

Put a panic loop between the vector table and the main code?

Here:
         ;bang I/O pin
         rjmp here


I use a routine called "Pong" a lot, which outputs a byte as PWM, 
where all byte values take the same time.
0s are narrow, 1's are wide.
For something like this, I'd load a unique value into TEMP, and call 
PONG on each ISR, so the output shows the int train.
You need a DSO or logic analyzer to catch it though.