用汇编语言给流水灯程序加一个外部中断暂停和启动

org 0000h
LJMP start
ORG 0003H
JNB P3.2, $
CPL TR1
RETI
start:
SETB TR1
SETB EX0
SETB EA
start1:
mov a, #0
mov p1, a ;LED全亮
acall delay
cpl a ;取反
mov p1, a ;LED全灭
acall delay
SJMP start1

delay:
mov r6, #20 ;子程序延时一秒
MOV TMOD, #10H
MOV TH1, #3CH
MOV TL1, #0B0H
LOOP1:
JBC TF1, LOOP2
AJMP LOOP1
LOOP2:
MOV TH1, #3CH
MOV TL1, #0B0H
DJNZ R6,LOOP1
RET

END