(IRQ) The name of an input found on many processors which
causes the processor to suspend normal instruction execution
temporarily and to start executing an interrupt handler
routine. Such an input may be either "level sensitive" -
the interrupt condition will persist as long as the input is
active or "edge triggered" - an interrupt is signalled by a
low-to-high or high-to-low transition on the input. Some
processors have several interrupt request inputs allowing
different priority interrupts.
