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TM4C123G Launchpad: Incapable of communicating with Putty

Robert Samuel
Intellectual 610 points

Hello, I am using a TM4C123G Launchpad.

Somehow while learning how to program it I managed to render it incapable of communicating with Putty.  I have tried to reset the board by using the process posted to me by Amit Ashara on Mar 15, 2015 at 7:22 AM with no success.

However, I am able to use the LM Flash Programmer to load a project, for example project0.bin, and have it successfully run.

The host PC is running Win7 with all the Stellaris drivers installed and working.  I see them on the Device Manager.  Also, I have second TM4C123G Launchpad that communicates and functions as expected with Putty.

Guidance on how to solve this problem will be greatly appreciated, and, if possible, an explanation of why I am having and created this problem.

Thanks! 

  • 0
    Guru 11940 points
    Have you tried to debug the non-working board ?

    Have you checked the signals of the VCP UART lines ?
    You should be able to measure the UART signals from the target to the on-board debug pod. (Check the schematics).
  • 0 in reply to f. m.
    Intellectual 610 points

    f. m. thank you for your suggestions.

    I'll will be on travel until the for the first week in August at which time I will test the VCP UART line signals.

    Is it possible for you to explain to me why the LM Flash Programmer will load the board while Putty will not communicate with it?

  • 0
    Guru 55913 points
    Hi Robert,
    I addition to f.m. comment please be sure to install virtual serial driver if not showing in device manager, assuming Win7^. LM flash can use the USB virtual CDM composite driver and will exist in same DVM if or when notified by Windows PNP manager it was detected. If the drivers are already installed not much happens other than connection confirmed on device tab.
  • 0 in reply to Robert Samuel
    Guru 11940 points

    Is it possible for you to explain to me why the LM Flash Programmer will load the board while Putty will not communicate with it?

    Assuming all the given information is correct (one of two identical board works, another not, you can flash the non-working board), and also the implicit informations are correct (drivers are correctly installed and working, COM port settings are matching), the VCP path is the difference.

    If you can flash/debug the board, it means the on-board debug pod (which happens to be the VCP-driving hardware as well) is working.

    And, assuming your target application is working, the UART lines from the target to the debug pod are left. However, I still don't rule out an application software issue on the target ...

  • 0 in reply to f. m.
    Guru 55913 points
    >The host PC is running Win7 with all the Stellaris drivers installed and working.

    Mine were too and then suddenly stopped without any real provocation.

    Petri not to long ago reminded me hidden devices sometimes don't show in device manager. Commands show orphaned virtual USB devices (greyed out) and simply delete them. The virtual serial COM driver will reinstall fixing the broken pipe. Windows team still has not fixed non persistent USB devices being orphaned from the XP platform days. Must be a nice job to let things like that fly under the radar.

    set devmgr_show_nonpresent_devices=1

    start devmgmt.msc
  • 0
    Guru 117855 points

    Robert Samuel said:
    Also, I have second TM4C123G Launchpad that communicates and functions as expected with Putty.

    Perhaps poster BP "missed" the above...   

  • 0 in reply to Genatco
    Intellectual 610 points
    Great guidance everyone, thank you. The explanations are all very helpful to me.

    There is one of BP101’s acronyms, DVM, I don't understand and can't find by Googling it. A definition will be helpful.

    As I mentioned in an earlier post I will not be back home to work on this until next week.

    Thanks again to all of you. Bob