SN8P2200 Series
USB 1.1 Low-Speed 8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 61
Version 1.7
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 instruction save and
load
ACC
,
PFLAG
data into buffers and avoid main routine error after interrupt service routine finishing.
¾
Note: ”PUSH”, “POP” instructions save and load ACC/PFLAG without (NT0, NPD). PUSH/POP buffer is
an unique buffer and only one level.
¾
Example: Store ACC and PAFLG data by PUSH, POP instructions when interrupt service routine
executed.
ORG
0
JMP
START
ORG
8
JMP
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