说明：  LCD1602位数据线连接方式及驱动程序,以往我们都是用的8根数据线进行通信,但完全可以省下4根数据线,以节省单片机端口资源
(LCD1602-bit data line connections and drivers, we are all used in the past eight data lines to communicate, but it can save four data lines in order to save resources Singlechip port)