使用python实现串口上位机的功能，可自动侦测PC有效串口号，选择串口波特率、校验位。同时可实现接收数据存储在TXT文件中。(Python is used to realize the function of serial port host computer. It can automatically detect PC valid serial port, select serial port baud rate and check bit. At the same time, the receiving data can be stored in the TXT file.)