实现对十字路口红绿灯的控制，含有外部中断，应对十字路口的突发情况。-To achieve the control of traffic lights at the crossroads, containing external interrupt, to deal with the intersection of the unexpected situation.

交通灯的中断正常使用以及出现重要突发情况的人工操作-Traffic lights interrupt normal use and the emergence of an important emergency situation of manual operation