SONIX SN8P2624 - 6.8 T0 Interrupt Operation

SN8P2624
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD Page 64 Version 0.3
6.8 T0 INTERRUPT OPERATION
When the T0C counter occurs overflow, the T0IRQ will be set to “1” however the T0IEN is enable or disable. If the
T0IEN = 1, the trigger event will make the T0IRQ to be “1” and the system enter interrupt vector. If the T0IEN = 0, the
trigger event will make the T0IRQ to be “1” but the system will not enter interrupt vector. Users need to care for the
operation under multi-interrupt situation.
¾ Example: T0 interrupt request setup.
B0BCLR FT0IEN ; Disable T0 interrupt service
B0BCLR FT0ENB ; Disable T0 timer
MOV A, #20H ;
B0MOV T0M, A ; Set T0 clock = Fcpu / 64
MOV A, #74H ; Set T0C initial value = 74H
B0MOV T0C, A ; Set T0 interval = 10 ms
B0BSET FT0IEN ; Enable T0 interrupt service
B0BCLR FT0IRQ ; Clear T0 interrupt request flag
B0BSET FT0ENB ; Enable T0 timer
B0BSET FGIE ; Enable GIE
¾ Example: T0 interrupt service routine.
ORG 8 ; Interrupt vector
JMP INT_SERVICE
INT_SERVICE:
… ; Push routine to save ACC and PFLAG to buffers.
B0BTS1 FT0IRQ ; Check T0IRQ
JMP EXIT_INT ; T0IRQ = 0, exit interrupt vector
B0BCLR FT0IRQ ; Reset T0IRQ
MOV A, #74H
B0MOV T0C, A ; Reset T0C.
… ; T0 interrupt service routine
…
EXIT_INT:
… ; Pop routine to load ACC and PFLAG from buffers.
RETI ; Exit interrupt vector