#include<reg51.h>
#define uchar unsigned char
#define uint unsigned int
sbit RED_A=P0^0; //东西向指示灯
sbit YELLOW_A=P0^1;
sbit GREEN_A=P0^2;
sbit RED_B=P0^3; //南北向指示灯
sbit YELLOW_B=P0^4;
sbit GREEN_B=P0^5;
//延时倍数，闪烁次数，操作类型
变量
uchar Time_Count=0,Flash_Count=0,Operation_Type=1;
//定时器0 中断函数
void T0_INT() interrupt 1
{
TL0=-50000/256;
TH0=-50000%256;
switch(Operation_Type)
{
  case 1: //东西向绿灯与南北向红灯亮 5s
    RED_A=0;YELLOW_A=0;GREEN_A=1;
    RED_B=1;YELLOW_B=0;GREEN_B=0;
    if(++Time_Count!=100) return; //5s（100*50ms）切换
    Time_Count=0;
    Operation_Type=2;
    break;
  case 2: //东西向黄灯开始闪烁，绿灯关闭
    if(++Time_Count!=8) return;
    Time_Count=0;
    YELLOW_A=~YELLOW_A;GREEN_A=0;
    if(++Flash_Count!=10) return; //闪烁
    Flash_Count=0;
    Operation_Type=3;
    break;  
  case 3: //东西向红灯与南北向绿灯亮 5s
    RED_A=1;YELLOW_A=0;GREEN_A=0;
    RED_B=0;YELLOW_B=0;GREEN_B=1;
    if(++Time_Count!=100) return; //5s（100*50ms）切换
    Time_Count=0;
    Operation_Type=4;
       break;   case 4: //南北向黄灯开始闪烁，绿灯关闭
    if(++Time_Count!=8) return;
    Time_Count=0;
    YELLOW_B=~YELLOW_B;GREEN_A=0;
    if(++Flash_Count!=10) return; //闪烁
    Flash_Count=0;
    Operation_Type=1;
    break;
}   
}
//主程序
void main()
{
TMOD=0x01;    //T0 方式 1
IE=0x82;
TR0=1;
while(1);
}