? 键盘在单片机应用系统中，实现输入数据、传送命令的功能，是人工干预的主要手段。键盘分两大类：编码键盘和非编码键盘。(In the application system of single chip microcomputer, keyboard is the main means of manual intervention, which can realize the function of input data and command. The keyboard is divided in