ORG 00H
AJMP MAIN
ORG 0030H
MAIN:
K BIT P3.0
JIAN:JB K,NIE

M:LCALL DELAY
JB K,JIAN
MOV P1,#0FEH
AJMP MAIN
NIE:MOV P1,#0FFH
AJMP M
DELAY:
MOV R1,#20
D1:MOV R2,#20
D2:MOV R3,#248
DJNZ R3,$
DJNZ R2,D2
DJNZ R1,D1
RET
END