Why does the Rabbit have multiple interrupt priorities?
A. The Z180 or Z80 has a single priority of interrupts plus the nonmaskable interrupt. The Rabbit has four levels of priority that the processor can operate at. There are three levels of priority associated with interrupts. This allows for super priority interrupts that can interrupt lower priority interrupts. This guarantees a fixed response time for at least one super priority interrupt, allowing very fast response to critical events. The interrupt priority of on-chip peripheral devices is programmable as it the priority of the external interrupt request pins.
