程序如下:用P1口做输出
ORG 0200H
START: MOV R0,#0F8H
MOV R1,#80
LOOP1: MOV P1,R0
MOV A,R0
RL A
MOV R0,A
ACALL DELAY
DJNZ R1,LOOP1
MOV R1,#80
LOOP2: MOV P1,R0
MOV A,R0
RR A
MOV R0,A
ACALL DELAY
DJNZ R1,LOOP2
LJMP START
DELAY: MOV R2,#0
D1: MOV R3,#0
DJNZ R3,$
DJNZ R2,D1
RET
END