Interrupt Vectors: Int0 - Eir,00H/Int1 - Eir,08H - Rabbit 3000 User Manual

7.9.2 Interrupt Vectors: INT0 - EIR,00h/INT1 - EIR,08h

When it is desired to expand the number of interrupts for additional peripheral devices, the
user should use the interrupt routine to dispatch interrupts to other virtual interrupt rou-
tines. Each additional interrupting device will have to signal the processor that it is
requesting an interrupt. A separate signal line is needed for each device so that the proces-
sor can determine which devices are requesting an interrupt.
The following code shows how the interrupt service routines can be written.
; External interrupt Routine #0 (programmed priority could be 3)
int2:
push ip ; save interrupt priority
ipset 1 ; set to priority really desired (1, 2, etc.)
; insert body of interrupt routine here
;
pop ip ; get back entry priority
ipres ; restore interrupted routine's priority
ret ; return from interrupt
92 Rabbit 3000 Microprocessor