SONIX SN8P2624 - 6.10 Multi-Interrupt Operation

SN8P2624
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD Page 66 Version 0.3
6.10 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.
T0IRQ T0C overflow.
TC1IRQ TC1C overflow.
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 INTT0CHK ; Jump check to next interrupt
B0BTS0 FP01IRQ ; Check P01IRQ
JMP INTP01 ; Jump to INT1 interrupt service routine
INTT0CHK: ; Check T0 interrupt request
B0BTS1 FT0IEN ; Check T0IEN
JMP INTTC1CHK ; Jump check to next interrupt
B0BTS0 FT0IRQ ; Check T0IRQ
JMP INTT0 ; Jump to T0 interrupt service routine
INTTC1CHK: ; Check TC1 interrupt request
B0BTS1 FTC1IEN ; Check TC1IEN
JMP INT_EXIT ; Jump to exit of IRQ
B0BTS0 FTC1IRQ ; Check TC1IRQ
JMP INTTC1 ; Jump to TC1 interrupt service routine
INT_EXIT:
… ; Pop routine to load ACC and PFLAG from buffers.
RETI ; Exit interrupt vector