设计一个简单自动控制的交通灯控制系统。具体要求，在道路十字路口的两个方向各设一组红绿指示灯，显示顺序为，其中一个方向是绿灯、黄灯、红灯，另一个方向是红灯、绿灯、黄灯；设置一组数码管，以倒计时的方式显示允许通过或禁止通过的时间，其中绿灯、黄灯、红灯的持续时间分别为80s/6s/40s。(Design a simple and automatic traffic light control system. The specific requirements in the two direction of the road crossroads, each with a set of red and green indicator light, display order, one direction is green, yellow light, red light, the other direction is a red light, green light, yellow light; set up a group of digital tube, with a countdown display allows or prohibited by the the duration of time, green light, yellow light, red light was 80s/6s/40s.)