SN8P2711A
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 72
Version 0.1
6.11 MULTI-INTERRUPT OPERATION
Under certain condition, the software designer uses more than one interrupt requests. Processing multi-interrupt
request requires setting the priority of the interrupt requests. The IRQ flags of interrupts are controlled by the interrupt
event. Nevertheless, the IRQ flag “1” doesn’t mean the system will execute the interrupt vector. In addition, which
means the IRQ flags can be set “1” by the events without enable the interrupt. Once the event occurs, the IRQ will be
logic “1”. The IRQ and its trigger event relationship is as the below table.
Interrupt Name
Trigger Event Description
P00IRQ
P0.0 trigger controlled by PEDGE.
P01IRQ
P0.1 falling edge trigger.
TC0IRQ TC0C
overflow.
TC1IRQ TC1C
overflow.
ADCIRQ ADC
converting
successfully.
For multi-interrupt conditions, two things need to be taking care of. One is to set the priority for these interrupt requests.
Two is using IEN and IRQ flags to decide which interrupt to be executed. Users have to check interrupt control bit and
interrupt request flag in interrupt routine.
¾
Example: Check the interrupt request under multi-interrupt operation
ORG
8
; Interrupt vector
JMP
INT_SERVICE
INT_SERVICE:
…
; Push routine to save ACC and PFLAG to buffers.
INTP00CHK:
;
Check
INT0 interrupt request
B0BTS1
FP00IEN
; Check P00IEN
JMP
INTP01CHK
; Jump check to next interrupt
B0BTS0
FP00IRQ
; Check P00IRQ
JMP
INTP00
; Jump to INT0 interrupt service routine
INTP01CHK:
;
Check
INT0 interrupt request
B0BTS1
FP01IEN
; Check P01IEN
JMP
INTTC0CHK
; Jump check to next interrupt
B0BTS0
FP01IRQ
; Check P01IRQ
JMP
INTP01
; Jump to INT1 interrupt service routine
INTTC0CHK:
; Check TC0 interrupt request
B0BTS1
FTC0IEN
; Check TC0IEN
JMP
INTTC1CHK
; Jump check to next interrupt
B0BTS0
FTC0IRQ
; Check TC0IRQ
JMP
INTTC0
; Jump to TC0 interrupt service routine
INTTC1CHK:
; Check TC1 interrupt request
B0BTS1
FTC1IEN
; Check TC1IEN
JMP
INTADCHK
; Jump check to next interrupt
B0BTS0
FTC1IRQ
; Check TC1IRQ
JMP
INTTC1
; Jump to TC1 interrupt service routine
INTADCHK:
; Check ADC interrupt request
B0BTS1
FADCIEN
; Check ADCIEN
JMP
INT_EXIT
; Jump to exit of IRQ
B0BTS0
FADCIRQ
; Check ADCIRQ
JMP
INTADC
; Jump to ADC interrupt service routine
INT_EXIT:
…
; Pop routine to load ACC and PFLAG from buffers.
RETI
; Exit interrupt vector
