SONIX SN8P2501D - T0 Interrupt Operation

SN8P2501D
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD Page 57 Version 1.5
6.7 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.
 Example: T0 interrupt request setup. Fcpu = 16MHz / 16.
B0BCLR
FT0IEN
; Disable T0 interrupt service
B0BCLR
FT0ENB
; Disable T0 timer
MOV
A, #20H
;
B0MOV
T0M, A
; Set T0 clock = Fcpu / 64
MOV
A, #64H
; Set T0C initial value = 64H
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
Example: T0 interrupt service routine as no RTC function.
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, #64H
B0MOV
T0C, A
; Reset T0C.
…
; T0 interrupt service routine
…
EXIT_INT:
…
; Pop routine to load ACC and PFLAG from buffers.
RETI
; Exit interrupt vector