说明：  51单片机模拟PS2键盘，当接收到触发信号时，向PC发送特定键值，从而达到预期的目的，可以用在很多工控场合。本程序已经通过开机自检，可以在设备管理器里面看到。
(51 single-chip analog PS2 keyboard, when receiving the trigger signal to the PC to send a specific key, so as to achieve the intended purpose, can be used in many industrial applications. This program has passed POST, you can see inside the device manager.)