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Thread: Teensy 4.0 not showing up as 16c0:0486 but 1fc9:0135

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  1. #1
    Junior Member
    Join Date
    Jan 2021

    Teensy 4.0 not showing up as 16c0:0486 but 1fc9:0135

    This is my first post here. So hello everyone! I am happy to become part of this great community.

    I have a problem with my T4.0 not showing up as ttyACM.
    I have multiple Teensy LCs and both a Teensy 4.0 and a Teensy 4.1 and running a Manjaro Linux machine.
    When connecting the boards to USB they all correctly identify as "16c0:0486 Van Ooijen Technische Informatica Teensyduino RawHID" and the udev rules add the ttyACM.
    But when I connect the T4.0 it identifies as "1fc9:0135 NXP Semiconductors SE Blank RT Family".

    The only thing I did to the T4.0 was soldering the Audio Shield Rev D. But I didn't check the T4.0 before.
    Could there be an issue with my soldering? Or is there an issue with the Teensy itself?

    Thanks in advance

  2. #2
    Senior Member+ KurtE's Avatar
    Join Date
    Jan 2014
    Note: the Teensy boards will not show up as a USB Serial device, unless you program them to do so.

    What I typically do with a new teensy, is to load up a simple sketch like the example blink,
    Set the Device as to what type of Teensy and USB type of Serial (default) I am going to program, then click the verify button in Arduino... This should build the sketch and then bring up the teensy app. Once that app is up, I then press the program button on the teensy, and you should see the Teensy sketch go through and program the new teensy. At which point it should load up as a proper teensy.

    However if you still have problems I would check your soldering to make sure there are no solder bridges and the like. And if that still does not work...

    Note again if you program a Teensy as for example USB Type of Raw Hid, it will not show up as ttyACM it will show up in a different place in the device tree. It has been awhile since I played much with Linux, so don't remember where.

  3. #3
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Quote Originally Posted by konrad View Post
    Could there be an issue with my soldering?
    Yes, very likely.

    Look for problems near pin 8. If stray solder got onto the pins of that little chip near pin 8, it would cause this sort of problem.

    And just to be clear, this problem almost certainly means the main processor isn't able to access that little flash chip anymore. So most of the normal troubleshooting (like the 15 second button press) won't work if the hardware can't access its flash memory.

    If the board hasn't ever been programmed, when you fix the problem it will probably boot right up as 16c0:0486 (RawHID) and the orange LED will blink.

  4. #4
    Junior Member
    Join Date
    Jan 2021
    Thanks KurtE and Paul for your very helpful avices!

    It's my bad. I am using Makefiles (like with my other Teensy LC project) so I copied the one from cores/teensy4 forgetting that I incorporated changes from teensy-template's Makefile to allow compilation of the complete project.
    So the same as

    As you suggested I managed to get blink running again using the Arduino IDE.
    So at least my soldering skills are alright

    Thanks again for you help!

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