PROTEUS的简单例子

				FLAG			BIT 00H
							ORG 00H
				START:			JB P1.7,START
							JNB FLAG,NEXT
							MOV R2,#200
				DV:			CPL P1.0
							LCALL DELY500
							LCALL DELY500
							DJNZ R2,DV
							CPL FLAG
				NEXT:			MOV R2,#200
				DV1:			CPL P1.0
							LCALL DELY500
							DJNZ R2,DV1
							CPL FLAG
							SJMP START
				DELY500:		MOV R7,#250
				LOOP:			NOP
							DJNZ R7,LOOP
							RET
							END