[Jeff McCune]

Originally Posted by Apollo Clark

So, when does the processor check the interrupt registers?

I think you're missing the point of interrupts. It's not that the function is executed anywhere you're code is running. This is true, but this is just a side-effect of the real purpose of interrupts.

Interrupts provide a way for the harware to be notified of an *event* versus the hardware frequently checking if an event happened sometime in the past. You don't *have* to use interrupts for a simple digital switch, but you might as well. I'm a big fan of not wasting resources, if I have interrupts left over, I'll use them for a trivial task such as this. My logic is, why waste time checking something if I can be told when it happens.

Also, if this controler has "true" interrupts, then the hardware doesn't need to "check the registers." Asserting an interrupt pin on the chip will literally *interrupt* execution and force execution of the interrupt handler. Doesn't need to check anything.