说明：  通过矩阵键盘向液晶1602中写入数据（16个按键分别代表1234567890ABCDE其中第16个按键作用是清屏光标返回）
(Through the matrix of the keyboard to the LCD 1602 in the write data (16 keys represent the first of which 1234567890ABCDE key role of 16 ching-screen cursor to return))