- One possibility is that your test harness might not be functioning properly, for this you can check the following documentation from MathWorks on how to create a test harness
- Check that the port settings in your harness test are properly configured to match the settings used by your hardware and MATLAB e.g. baud rate, data bits, parity etc.
- Verify the connection and ensure that the harness is properly configured to pass the messages between the hardware and the test environment.