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LAUNCHXL-F28379D: How to enable connection to FTDI driver without a hardware reset?

Adam Jones
Intellectual 460 points
Part Number: LAUNCHXL-F28379D

I've been using the LAUNCHXL-F28379D for over a year now, and there is one oddity that I haven't been able to figure out.

Regardless of the host OS, if I plug the LaunchXL into the computer and immediately try to communicate with it, it will never work. However, if, while connected, I press the reset button the LaunchXL, then data will work in both directions. I can see from the FTDI LEDs that data is being received from the computer, but I've verified that the F28379D cannot read it.

I've thought this could possibly be because I've set my baud rate to 921600 on SCI. However, whatever terminal or serial port software I use also sets the same baud rate when opening the port.

Is there something I'm missing? Is there a way to "reset" the FTDI chip from the host end? 

  • 0
    Intellectual 460 points
    I've verified that if I add code to regularly send from the launchxl (could be a string, or just a linefeed), that the FTDI chip will grab the correct baud and send this through to the OS with a "cold connection" (plugging straight into USB without rebooting F28379D). However, although the FTDI rx LED lights up when sending the data from the computer to the launchxl, nothing is received by the F28379D. This is strange.
  • 0 in reply to Adam Jones
    Intellectual 460 points
    Update, and for future reference.

    When I added a pause of at least 0.1 seconds after boot before initializing the SCI and sending the first bytes, the FTDI chip is able to correctly detect the baud and allow bi-directional communication upon a "cold connection".
  • 0 in reply to Adam Jones
    TI__Guru** 113755 points
    Hi Adam,
    Glad to see you were able to resolve the issue and also posted the solution which will be useful for others.

    Regards,
    Vivek Singh