Troubleshoot the Raspberry Pi Serial Port
Missing or Garbled Data
When you try to exchange data with the serial device, the data is garbled or missing.
Creating a connection and writing data to a serial device does not provide any indication of success or failure.
The device is not connected to the Raspberry Pi™ serial port. Or, the connection to the serial device is not configured correctly.
To solve this issue, do the following:
Verify the physical connection between the Rx and Tx pins and their counterparts on the serial device.
Verify the serial port settings that the serial device requires. Clear the handle for the current serial connection. Create a new connection that uses the correct serial port settings.
Verify the data precision that the serial device requires. Write data using the correct serial port settings.