用交叉串口线连接两块单片机进行双机通信，扫描到有键按下时，键值发送出去，另一块板收到后以0-F方式显示在数码管上。-With cross-serial cable to connect two pairs of aircraft communications microcontroller to scan that there are key is pressed, the key to send out another one after the board received 0-F are displayed in the digital pipe.