This file contains ambiguous Unicode characters that may be confused with others in your current locale. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to highlight these characters.
功能说明：首先通过串口打印“Hello World!"；然后等待上位机发送，并将接收到的上位机发送内容原封不动的发送回上位机。。