就是将上面的按键控制小灯的实验扩展成3 个按键对应3 个小灯，占用6 个数字I/O 接口,来实现对小灯的控制(It is to expand the above key control light experiments to 3 keys corresponding to 3 small lights, 6 digital I/O interface, to realize the control of the light.)