中南大学单片机交通灯课程设计，程序实现功能：

1.在一个十字路口的一条主干道和一条支干道上分别装上一套红、黄、绿3种信号灯，

用钮子开关模拟十字路口的车辆检测传感器信号。在一般情况下，主干道上的绿灯常亮，而支干道总是红灯。

2.当检测到支干道上来车时（用按键开关模拟），主干道的绿灯转为黄灯，持续4S后，又变为红灯，同时支干道由红灯变为绿灯。

3.支干道绿灯亮后，或者检测到主干道上来了3辆（用3个钮子开关模拟），或者虽未来3辆车，

但绿灯已经持续了25s，则支干道立即变为黄灯，4s后转为红灯，同时主干道由红灯变为绿灯。

4.当有紧急情况时，如有120救护车，119救火时等情况，所有车让路，主干道支干道变红灯。-Central South University microcontroller traffic lights curriculum design, program functions: a crossroads of a main road and a branch roads were fitted with a set of red, yellow, green, three kinds of signal lights, toggle switch analog crossroads vehicle detection sensor signal. In the general case, the green light is on the main road, branch roads always red light. When the detected the branch roads up car to (key switch analog), the main road the green light to a yellow light, red light, and becomes continuous 4S, and branch roads by the red light turns green. 3. Branch roads green light, or detected by the main road up the three (3 Toggle Switches Analog), or the next three cars, but the green light has been going on 25s, branch roads immediately becomes yellow, 4s turns red, the same time the main road by the red light turns green. When the emergency, subject to 120 ambulances, 119 fire fighting, all car make way, the main road branch roads goes red.