单片机通过中断和计算机进行通信，首先接收联机指令，然后接收计算机的相关控制指令。采用发送不同的字符给计算机，来对接收到的不同的计算机控制指令进行反馈，从而使单片机实时接收计算机的指令，实现视频信号的切换。

-Through the single-chip interrupt and computer communications, first receiving on-line instruction, then the receiving computer related control instructions. Using a different character to the computer, the received different computer control instruction feedback, so that the single chip computer real time receiving a computer instruction, realizes the switching of the video signal