设计一个简单的十字路*通灯。交通灯分东西和南北两个方向，均通过数码管和指示灯指示当前的状态。设两个方向的流量相当，红灯时间45s，绿灯时间40s，黄灯时间5s。-Design a simple traffic lights at a crossroads. Traffic lights at East-West and North-South in both directions, both through the digital control and the current status indicator instructions. Established a considerable traffic in both directions, the alarm time 45s, green time of 40s, yellow time 5s.