说明：  基于8051通过串口测试4*4矩阵键盘，通过键盘按键发送A-F字符到串口调试助手。本程序可通过加LCD1602接受串口发送过来的数据。
(Based on 8051 through the serial port test 4* 4 matrix keyboard, the keyboard keys send characters to the serial debug AF assistant. This program can be sent by Canada LCD1602 received over the serial port data.)