signal1:
MOV A,#11011110B 
MOV P1,A
CLR A
CALL delayL 
MOV A,#11101110B 
MOV P1,A
CLR A
CALL delayS 
CALL signal2 
signal2:
MOV A,#11110011B 
MOV P1,A
CLR A
CALL delayL
MOV A,#11110101B 
MOV P1,A
CLR A
CALL delayS
CALL signal1
delayL:
MOV R3,#20H
DJNZ R3,$
RET
delayS:
MOV R3,#10H
DJNZ R3,$
RET