#include<reg52.h>sbit LED_Yellow = P0^1; //单片机 P0.1 脚
 sbit LED_Green = P0^2; //单片机 P0.2脚void Delay();
void main(){
 while(1){
 Delay(); //随便一个延时程序
 LED_Yellow = 0; //黄灯亮
 LED_Green = 1; //绿灯灭
 Delay ();
 LED_Yellow = 1; //黄灯灭
 LED_Green = 0; //绿灯亮
 }
 }void Delay()
 {
 unsigned char h, i, j, k;
 for (h = 5; h > 0; h–)
 for (i = 4; i > 0; i–)
 for (j = 116; j > 0; j–);}