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Linux/TM4C1294NCPDT: ttyACM0 default configuration

Part Number: TM4C1294NCPDT

Tool/software: Linux

Hi,

We are attempting to interface a Raspberry PI running Raspbian Stretch to a board we designed using the TM4C1294 micro through a USB port using the default Virtual Com Driver.  On power up, text that our board sends out is being echoed back by the Raspberry PI before the application we are running on the Raspberry PI has a chance to start and turn off the echo.  The echoed back text is not recognized by the firmware on our board and it generates an error message that is sent out and also echoed back.  If our application does not start soon enough this snowballs and ends up locking up the port.  Is there any way to change the default configuration of the Virtual Com Driver so that it will not echo on power up?

We know we could modify our firmware to handle this, however we have already shipped hundreds of units with this board.  We will be supplying the Raspberry PI as part of a new add on feature that can be used with these old units and so we are hoping to find a solution that we can implement in the Raspberry PI only.

Thanks,

Scott

  • Hello Scott,

    I think I more or less understand the problem at hand but what I am not fully following is how you would like to solve the problem. Are you looking for a solution where the board with the TM4C is unchanged and operates as described, and just need help with trying to address how to handle the fix on the Raspberry PI?
  • Hi Ralph,

    That is correct.  We can't change the board or firmware.  So we are hoping there is something we can change in the Raspberry PI.  We have tried sending an STTY command from rc.local to turn off the echo, but it appears this occurs too late.  We are hoping there is something that can be done so that it starts up with echo off.  But we are new to Linux and so don't know much about how drivers are loaded, etc.

    Thanks,

    Scott

  • Hi Scott,

    I asked about and unfortunately since the Raspberry PI does not use a TI processor we can't help support it. If you end up trying to change the TM4C board, then please feel free to open up a thread then, but for the Raspberry PI you will need work the vendor who makes it to get support for the Linux changes. Best of luck, and sorry we couldn't help more.
  • No problem. I knew it was a long shot asking this question here, but thought I would try since it is related to the driver that communicates with the TM4C.

    Thanks,
    Scott