本程序设计需应用软件控制并运行接口电路，使连接在该接口上的红、绿、黄发光二极管按十字路*通红、绿、黄灯形式闪烁，并显示绿灯的倒计时时间。

　　　　程序一开始，四个方向的灯全为红灯，接着变为黄灯闪烁，然后东西方向为红灯，南北方向为绿灯并显示倒计时时间，倒计时间结束后，交通灯变成黄灯，闪烁几次后，东西方向变成绿灯，南北变成红灯，再变成黄灯，如此按交通灯的变化规则交替变化。

-This procedure required the design of application software to control and run the interface circuit to connect the interface of the red, green, yellow light-emitting diode according to a crossroads of traffic red, green, yellow form of flashing, and display the countdown time for the green light. Procedure, the four directions of all the red lights, then into a yellow light flashes, and then east-west direction for a red light, green light for north-south direction and display the countdown time between the end of the countdown, the traffic light into yellow light, blinking several times after the green light into an east-west direction, north and south into the red, and then into a yellow light, so the traffic light changes according to the rules of the turn changes.