急救车与交通灯）（1）南北与东西方向，每个方面由红黄绿三个灯控制（2）南北向：　红（30秒），黄（5秒），绿（25秒）　　　东西向： 红（35秒），黄（5秒），绿（25秒）　　　上述基本参数可以根据实际情况自行调整，灯的变化规律与实际路口规律相同，绿灯在最后5秒钟时，黄灯亮，然后红灯亮，不允许两个方面同时亮绿灯。（3）绿灯的时间显示在数码管上进行显示。（4）可以通过一个开关控制，当开关信号为0时，整个交通灯全灭提高要求：（1）设计一个紧急控制开关信号，当紧急开关信号为1时，两个方向的灯全为红灯。紧急开关撤消后，按照开关按下之前的状态继续运行（其参数要保存）。（2）设计一个夜间行车开关，当开关按下后，两个方向都只有黄灯闪烁，其它灯熄灭。（3）设计两个方向的亮时时间可调。-emergency vehicles and traffic lights) (1) North and South and east-west direction, each with three yellow-green from red lights control (2) to the north and south : red (30 seconds), yellow (5 seconds), Green (25 seconds) to things : red (35 seconds), yellow (5 seconds) Green (25 seconds) above basic parameters can be adjusted to the actual situation, the light changes with the actual law of the same intersection, the green light in the final five seconds, the yellow light is on, and then a red light, bright, not two fronts simultaneously bright green. (3) the green light at the time displayed on the digital display control. (4) can be controlled by a switch, when the switch signal to 0, the whole prospect of traffic lights to improve requirements : (1) Design an emergency control switch