按照RS-232C协议要求，利用单片机串行口，实现通信数据的自发自收功能。发送数据从键盘键入，接受数据送到七段LED显示器显示出来，观察键入数据与显示数据的一致性。-In accordance with RS-232C protocol requirements, the use of microcontroller serial port to achieve the spontaneous communication data received from the function. Send