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。-A self-made microcomputer minimum system, including serial download, reset circuit, using the internal timer control things north and south, traffic signal lamp (using the LED simulation), traffic signal lights　red, yellow, green, composed, things north and south by 12 Road intersection simulation LED composition, wherein, both north and south what is in parallel connection, two-way are countdown card. A self-made microcomputer minimum system, including serial download, reset circuit, using the internal timer control things north and south, traffic signal lamp (using the LED simulation), traffic signal lights　red, yellow, green, composed, things north and south by 12 Road intersection simulation LED composition, wherein, both north and south what is in parallel connection, two-way are countdown card.