设计一个用于十字路口的交通灯控制器。

基本要求：

东西和南北方向各有一组红、黄、绿灯用于指挥交通，红、黄、绿的持续时间分别为25s，5s，20s。 当有紧急情况（如消防车）时，两个方向均为红灯亮，计时停止，当特殊情况结束后，控制器恢复原来状态，正常工作。 一组数码管，以倒计时方式显示两个方向允许通行或禁止通行的时间。

-Design a controller for a traffic light intersection. Basic requirements: north-south direction things and have a group of red, yellow, green light for directing traffic, red, yellow and green are the duration of 25s, 5s, 20s. When there is an emergency situation (such as fire engines), the two directions are the red light, time stops, when the end of special circumstances, the controller to restore the original state of work. A set of digital control, the countdown is displayed in both directions to allow access or prohibit the passage of time.