1基本部分

本实验模拟交通信号灯控制，一般情况下正常显示，有急救车到达时，两个方向交通信号灯全红，以便让急救车通过。设急救车通过路口时间为5秒，急救车通过后，交通恢复正常，本实验用单次脉冲申请外部中断，表示有急救车通过。

本实验红灯每次亮10秒，黄灯1.5秒闪烁三次，绿灯亮8.5秒，所有需要定时的时间都需要通过定时器定时。

2 提高部分

有急救车通过时，将表示东西南北状态灯信息通过串行口发送到上位机。（其中高四位表示东西向，首位为1，然后是红黄绿，低四位代表南北向，首位为0，然后是红黄绿）

-1 basic parts

The experimental simulation of traffic signal control, generally display properly, when the ambulance arrived, two direction traffic signal lamp Quanhong so that emergency vehicles through. Set up a first aid car through the intersection time is 5 seconds, the emergency vehicle passed, the traffic returned to normal, this experiment with a single pulse to apply for external interrupt, said there are emergency vehicles through.

This experiment red light every time 10 seconds, yellow light 1.5 seconds flashing three times, the green light 8.5 seconds, all the time required by the timer timing.

2 improve part

The ambulance has passed, will represent the four corners of the world to the host computer through the status information of the serial port to send. (where high four said something to the first one, then red, yellow, and green, low four representatives　the north and south to 0 first, then red, yellow, and green)