熙熙攘攘的街头，人流车水有条不紊地行进着，靠的是交通灯的指挥作用，交通灯的绿、红、黄灯交替工作着，指挥着交通，维持着秩序。
　　　 课程设计采用单片机AT89C51为中心器件来设计交通灯，从而模拟十字路口交通灯的各种状态显示。设计由单片机AT89C51，LED八位数码显示管等组成。软件上采用C语言编程实现。主要编写了主程序，数码管显示程序和延时程序，经模拟，实现交通灯的功能。操作简单，设计简单易懂，但由于采用的是纯延时，因此会有一定的误差，但不影响总体效果。
　　　　在遇紧急情况时，可通过按键控制交通灯全亮红灯，从而解决紧急情况的交通问题。(Bustling streets, traffic cars, water methodically moving, relying on the command of the traffic lights, traffic lights green, red and yellow lights alternating work, directing traffic, maintaining order.
The curriculum design uses the single chip microcomputer AT89C51 as the central device to design the traffic lights, thus simulates each kind of status display of the intersection traffic lights. Design by SCM, AT89C51, LED, eight bit digital display tube and so on. The software is programmed with C language. Mainly written in the main program, digital display procedures and delay procedures, by simulation, to achieve traffic lights function. The operation is simple, the design is simple and easy to understand, but because of the adoption of pure delay, there will be some errors, but it does not affect the overall effect.
In case of emergency, the traffic lights can be controlled by a button to complete the red light, thus solving the traffic problems in an emergency.)