? 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 into two major categories: the coded keyboard and the non - coded keyboard.)