I'm sorry if such a topic already exists but i couldn't find anything about it(and i have read "Interrupts for Dummies"

).
i was trying to understand the default code and i have a few questions about using interrupts.
in the user_routines_fast.c there's a function called interrupt handler, but i can't seem to find what triggers it within the code. is there some section of the code that interrupts the regular processor activity and calls this function or does the processor do it itself. if so, is it the master processor or the user processor?