说明：  基于AVR 8位系列单片机的ps/2协议实现程序，可以实现单片机模拟键盘与主机通讯，包括发送一字节，接收一字节，发送位，接收位等。
(Microcontroller-based AVR 8-bit families of ps/2 protocol program, you can simulate the keyboard and the host MCU communications, including sending a byte, receive a byte, sending bits, the receiver position and so on.)