数字I/O实验主要完成的功能：

在此实验中，SEED-DEC5416 首选进行初始化，包括对外设 UART、本身频率的设定及一些状态区的初始化。然后等待 SEED-MMI5402 发送命令；SEED－DEC5416 响应交通灯自动模式、交通灯手动手动模式、交通灯东西通、交通灯南北通、及交通灯的禁行与夜间模式的操作命令。同时还响应，对 SEED-DEC5416 的复位及两个单元之间的通讯故障。

-Digital I/O completion of the experiment the main features: In this experiment, SEED-DEC5416 preferred to initialize, including peripherals UART, their frequency settings and some of the initialization state of the district. SEED-MMI5402 and then wait to send commands　SEED-DEC5416 automatic mode in response to traffic lights, traffic lights manual manual mode, the traffic light east-west pass, pass traffic lights north and south, and traffic lights at night and cut-line mode command. At the same time, also responded to the SEED-DEC5416 reset and communication between two modules fault.