了解485通信在DSP中的应用，运行此程序后，然后打开串口调试工具，发送一字节，通过串口线和适配器后，DSP收到一字节，然后在转发回去给PC。-About 485 in the DSP application, run this program, then open the serial port debugging tool, send a byte through the serial cable and adapter, DSP receive a byte, and then trans