标准键盘相当于一个独立的I/O 设备,它是一个各按键在内部排列成若干行和列的开关矩阵,可在单片机控制下进行工作。图1所示是一个83键键盘,每当按下一个键钮,就等于接通一交叉点上的一个开关,于是产生一个信号,此信号由单片机处理转换成一个特殊码,即键盘扫描码,单片机每3至5毫秒将逐列扫描一次,扫描到某列时,就将该列接为0电位,如 The standard keyboard is equivalent to a separate I / O device. It is a switch matrix with each key arranged in rows and columns internally, and can work under the control of a singlechip. Figure 1 shows an 83-key keyboard. Each press of a key button is equivalent to turning on a switch at a cross point, resulting in a signal that is converted by the microcontroller into a special code, the keyboard scan code , SCM scan every 3 to 5 milliseconds column by column, scan to a column, the column will be connected to 0 potential, such as