按键控制流水灯 左 右

（一）使用灌电流方式，P1口或P2外接8个发光二极管。编程序，控制发光二极管按一定的频率（2～5赫兹）循环点亮。
ORG 00H
START:
MOV A, #0FEH
MOV R6,#0
MOV R1,#8
AJMP MAIN
ORG 0013H
CJNE R6,#1,INT_1
SJMP INT_11
MAIN:
MOV SP,#60H
MOV P2, A
SETB IT1
SETB EA
SETB EX1
SJMP $
INT_1:
RL A
MOV P2,A
CALL DELAY1S
DJNZ R1,INT_1
MOV R1,#8
MOV A, #0FEH
MOV R6,#0
INC R6
RETI
INT_11:
RR A
MOV P2,A
CALL DELAY1S
DJNZ R1,INT_11
MOV R1,#8
MOV A, #0FEH
MOV R6,0
RETI
DELAY1S:
MOV R3,#0A7H
DL1:
MOV R4,#0ABH
DL0:
MOV R5,#1H
DJNZ R5,$
DJNZ R4,DL0
DJNZ R3,DL1
NOP
RET
END