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stellaris launchpad (LM4F120H5QR)

Grace Jones
Prodigy 20 points


My team has a stellaris launchpad (LM4F120H5QR). We were using Code Composer Studio to program our board. I was had loaded the usb_dev_serial example that was preloaded in code composer studio. I then switched from the USB power/ICDI to the USB connector device. During this the program crashed and now our stellaris will not connect with the computer. It says "failure to connect with target". The board is getting power but it is not being reconized by our computer. Is there some kind of manual reset tha can be done to reset the usb connection?? what do u recommend doing??

We tried running the ccs V5 eclipse  clean command but that did not work.

  • 0
    TI__Intellectual 2790 points

    Hello Grace Jones,

    If I understand you correctly, you had the Launchpad connected via the ICDI/Debug USB and had programmed the flash with a usb_dev_serial example from CCS. You then moved the cable from the ICDI/Debug connector to the Device connector and moved the PWR SELECT swtich to Device.

    At this point, CCS crashed? Was CCS in the debug perspective when you moved the cable?

    If you move the PWR SELECT switch to Debug and and plug in the USB cable to the ICDI/Debug connector, it is not recognized by CCS? Can you check to see if the PC detected and enumerated the Launchpad? Under Windows, you can check the Device Manager and look at the the "Ports" category. There should be a Stellaris COM Port or something similar listed there. If you are using Linux, you should be able to use 'lsusb' to see attached devices.  Be sure you are using the Debug connector port and verify that the PWR LED lights up with the cable attached.

  • 0 in reply to Stellaris Mitch
    Genius 5695 points

    fwiw...

    I had to re-solder the USB connectors on both my Stellaris Launchpad boards. I also had to replace USB cables. Both were causing non-contact and intermittent contact problems on my boards.

    Wasn't this issue raised before as well?

  • 0 in reply to Dave Robinson
    TI__Genius 17225 points

    Dave,

    Sorry for the problems you had with the Stellaris LaunchPad.  Initial production boards have a known sensitivity on the USB connectors.  The connectors surface mount pads are too far from the board edge.  This causes the flare on the outside of the connector to ride too high on the board edge resulting in a weak solder connection.  This problem has been resolved by modifying the PCB to move the connector further out to the board edge allowing connector to lay flatter during reflow.  

    I have only previously seen an issue with one cable.  We will be watchful for this and if the problem is widespread will investigate changing cable suppliers.

    Thank you for the report.

    Dexter