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Original question:

TM4C123GH6PM: USB device not recognized by PC

TM4C123GH6PM: USB CDC device isn't showing as COM device in device manager (Stellaris Device Firmware Update)

Karim El-Rayes
Intellectual 730 points
Part Number: TM4C123GH6PM
Other Parts Discussed in Thread: EK-TM4C123GXL

Hello,

I'm using the "usb_dev_serial" example to create a USB-CDC device using TM4C123G MCU on a custom board (non-Launchpad board). The device manager is showing "Stellaris Device Firmware Update" instead a COM port device. I tried to uninstall the USB driver and install the CDC one located within the TivaWare directory (located in \ti\TivaWare_C_Series-2.1.4.178\windows_drivers) without any luck. Did anyone had such an issue before?.

For what it is worth, the same example works fine with the TM4C123G launchpad, showing a USB-CDC device in the device manager.

Thanks,

Karim

  • 0
    TI__Guru**** 169336 points

    Hi,

      It does not make sense to me that the usb_dev_serial example is enumerated as a "Stellaris Device Firmware Update" instead of a COM port. I just ran the usb_dev_serial and it enumerated properly as a COM port. See below. 

     It is only when I run the boot_usb under C:\ti\TivaWare_C_Series-2.2.0.295\examples\boards\ek-tm4c123gxl\boot_usb will it enumerate as a  "Stellaris Device Firmware Update". See below. So the question to ask is if you really load the usb_dev_serial into the flash. Is it possible that you load the wrong program?

    Here is what I will suggest you do.

    - reload the usb_dev_serial again into your custom board?

    - if you have another fresh custom board, load the usb_dev_serial and will you see the same problem as the first board?

  • 0 in reply to Charles Tsai
    Intellectual 730 points

    Though it doesn't make sense yet it happened, even after reprogramming the MCU multiple times with the same firmware. Still it showed "Stellaris ICDI Firmware Upgrade" device in the device manager. However, I found the workaround, I follow this post and installed "LMFlash Programmer" Tool: 

    https://e2e.ti.com/support/microcontrollers/other/f/908/t/400294?Device-Manager-shows-Stellaris-Device-Firmware-Upgrade-when-Tiva-C-TM4C123GXL-Launchpad-is-connected

    I clicked the "Update" button in the tool and VOILA....the device is "Stellaris Virtual Serial Port" in the device manager. No explanation why that happened to my custom board. On another note, that doesn't happen with the TM4C123G launchpad.

    Hope that helps people in the future.

    Cheers,

    Karim

  • 0 in reply to Karim El-Rayes
    TI__Guru**** 169336 points

    Hi Karim,

      Interesting on your finding. It is still something I cannot explain. However, glad that your problem is solved. 

  • 0 in reply to Charles Tsai
    Intellectual 730 points

    Hi Charles,

    Unfortunately it's not 100% resolved yet, only the driver portion on the PC side. The MCU is appearing now as a USB CDC device in the device manager as I mentioned, but no the MCU isn't functioning for some reason!!. All functions implemented in the firmware don't seem to run. Worth noting, the part number is TM4C123GH6PMI, which is different than the one on the LP (TM4C123GH6PMT7). Could this be the issue?.

    Thanks,

    Karim

  • 0 in reply to Karim El-Rayes
    TI__Guru**** 169336 points

    Hi Karim,

      It is the same usb_dev_serial that you run on the lanchPad as well as on your custom board, right? If it works on the launchPad then we can rule out the software issue. I think it has something to do with your board. The difference between TM4C123GH6PMI and TM4C123GH6PMT7 is that the later works up to 105C rather than 85C. As far as the usb_dev_serial is concerned these two parts don't matter. 

      I also think the program was running for some extend. It would not enumerate and recognized by the Windows manager if the firmware didn't run. Can you confirm you are running the usb_dev_serial from the TivaWare library or it is your own code. 

  • 0 in reply to Charles Tsai
    Intellectual 730 points

    Hi Charles,

    Sorry for spamming the thread and your inbox. Everything works fine now, I did a little change: I was using a Tiva C 1294 LP to program my board, but then switched to TM4C123G LP as a programmer instead. Now the "usb_dev_serial" and "blinky" examples that come with the TivaWare package work fine. Thanks for working on the issue with me.

    Cheers,

    Karim

  • 0 in reply to Karim El-Rayes
    TI__Guru**** 169336 points

    Hi Karim,

     Glad your problem is resolved now!