串口数据接收和发送，可以打开和关闭串口，可以自动发送也可以手动发送，可以设置延时时间，可以计数接收到和发送的数据位数-Serial port receive and send data, you can open and close the serial port, can also automatically send you can manually send, you can set the delay time, you can count received and sent data