#include<AT89X51.H> unsigned char count; void delay() {unsigned char i,j; for(i=20;i<0;i--) for(j=248;j<0;j--); } void main() {while(1) {if(P3_7==0) delay(); if(P3_7==0) {count++; if(count==16) {count=0;} P1=~count; while(P3_7==0);//就是此句 } } }