Question

A type of interrupt we did not cover in class is the hardware exception. This interrupt is generated by the CPU when the execution of an instruction produces a condition which prevents it from completing. Some examples are: an attempt to divide by zero an attempt to take the square root of a negative number an attempt to divide infinity by infinity a page fault With respect to hardware exceptions: What must be allowed to complete before the interrupt is serviced? What resources (CPU, buses, memory, etc.) is the ISR expected to use? What is the ISR typically expected to resume after the ISR runs? What must be saved before the ISR is run?

Answer 1

a. Five conditions must be true for an interrupt to be generated

1) device arm,
2) NVIC enable,
3) global enable,
4) interrupt priority level must be higher than current level executing, and
5) hardware event trigger.

d.As interrupts stop a currently running process, the state of which must be saved before the interrupt is handled, there is a lag between the interrupt being generated and the ISR being run.