点亮一盏灯

	ORG 0000H
	SJMP START
	ORG 0030H
START:  MOV SP,#60H
		MOV P0,#0FFH
	
MAIN:   CLR P0.7
		CALL DELAY
		SETB P0.7
		CALL DELAY
		SJMP MAIN
		
DELAY:  MOV R0, #250
   D2:  MOV R1, #250
   D1:  DJNZ R1, D1
        DJNZ R0, D2
		RET
		END