51单片机交通灯，编程实现4盏LED的模拟交通灯，1、正常情况下，东西、南北方向轮流点亮交通灯;

好的，针对你的问题，以下是51单片机交通灯的编程实现：

#include <reg51.h>

sbit led_north_south_green = P1^0;  //南北方向绿灯
sbit led_north_south_yellow = P1^1; //南北方向黄灯
sbit led_north_south_red = P1^2;    //南北方向红灯
sbit led_east_west_green = P1^3;    //东西方向绿灯
sbit led_east_west_yellow = P1^4;   //东西方向黄灯
sbit led_east_west_red = P1^5;      //东西方向红灯

void delay(unsigned int x) //延时函数
{
    unsigned int i, j;
    for (i = x; i > 0; i--)
        for (j = 110; j > 0; j--);
}

void main()
{
    while (1)
    {
        led_north_south_green = 1; //南北方向绿灯亮
        led_north_south_yellow = 0;
        led_north_south_red = 0;
        led_east_west_green = 0;
        led_east_west_yellow = 0;
        led_east_west_red = 1; //东西方向红灯亮
        delay(5000);           //绿灯亮5秒钟
        led_north_south_green = 0;
        led_north_south_yellow = 1; //南北方向黄灯亮
        led_north_south_red = 0;
        led_east_west_green = 0;
        led_east_west_yellow = 1; //东西方向黄灯亮
        led_east_west_red = 1;
        delay(2000); //黄灯亮2秒钟
        led_north_south_green = 0;
        led_north_south_yellow = 0;
        led_north_south_red = 1; //南北方向红灯亮
        led_east_west_green = 1; //东西方向绿灯亮
        led_east_west_yellow = 0;
        led_east_west_red = 0;
        delay(5000); //绿灯亮5秒钟
        led_north_south_green = 0;
        led_north_south_yellow = 1; //南北方向黄灯亮
        led_north_south_red = 0;
        led_east_west_green = 0;
        led_east_west_yellow = 1; //东西方向黄灯亮
        led_east_west_red = 1;
        delay(2000); //黄灯亮2秒钟
    }
}

以上代码实现了4盏LED的模拟交通灯，正常情况下，南北方向和东西方向轮流点亮交通灯。代码中用到了延时函数来控制灯的亮灭时间。建议在测试时使用仿真器或者直接连接硬件进行调试。