自制一个单片机最小系统，包括串口下载、复位电路，采用内部定时器定时控制南北、东西的交通信号灯（采用LED模拟），交通信号灯由红、黄、绿灯组成，东西、南北模拟路口由12路LED组成，其中南北、东西均采用并联方式连接，双向均有倒计时牌-Homemade a single chip minimize system, including serial download and reset circuit, the inside timer timing control north and south, and things of traffic lights (using LED simulation), the traffic lights from red, yellow, and green composition, thing, north and south simulation by 12 road intersection LED, including north and south, and things are used parallel connection, two-way all have countdown card