protues8.6右侧led灯不亮是为什么

ORG 0000H
LJMP MAIN
ORG 0003H
LJMP INT_0
ORG 0100H
MAIN: SETB EA
SETB EX0
SETB IT0
MOV R3,#0
MOV P2,R3
HERE: SJMP HERE
ORG 0200H
INT_0: CLR EA
PUSH PSW
PUSH ACC
INC R3
MOV P2,R3
POP ACC
POP PSW
SETB EA
RETI
END