交通灯功能

1）对每个路口（主干道、次干道）的绿灯时间，及黄灯时间的设定。

2）设定参数掉电后不丢失（如果不使用EEPROM，此功能可以不实现）。

3）紧急按键功能，当按下该键时，所有路口变成红灯，相当于交警指挥特殊车辆通过。再按该键，恢复正常显示。-Traffic lights function

1) for each intersection (main road, the road) green time, and the yellow light time setting.

2) after power off set parameters is not lost (if not block using EEPROM, this function can not achieve).

3) emergency button function, when press the key, all become a red light intersection, the equivalent of special vehicles by the traffic police command. Press the key again, back to normal display.