SN8P2740 Series
ADC, OP-amp, Comparator 8-Bit Micro-Controller
6.5 PUSH, POP ROUTINE
When any interrupt occurs, system will jump to ORG 8 and execute interrupt service routine. It is necessary to save
ACC, PFLAG data. The chip includes “PUSH”, “POP” for in/out interrupt service routine. The two instructions save and
load ACC, PFLAG data into buffers and avoid main routine error after interrupt service routine finishing.
Note: ”PUSH”, “POP” instructions save and load ACC/PFLAG without (NT0, NPD). PUSH/POP buffer is
an unique buffer and only one level.
Example: Store ACC and PAFLG data by PUSH, POP instructions when interrupt service routine
executed.
ORG
JMP
0
START
ORG
JMP
8
INT_SERVICE
ORG
10H
START:
…
INT_SERVICE:
PUSH
…
; Save ACC and PFLAG to buffers.
…
POP
; Load ACC and PFLAG from buffers.
RETI
…
; Exit interrupt service vector
ENDP
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