Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 10 of 10

Thread: Teensy 4 Not Appearing as USB Device

  1. #1

    Teensy 4 Not Appearing as USB Device

    Hello, yesterday I was doing some very basic software testing on the Teensy 4. I don't believe that I had it connected to anything other than USB. When I tried to run some code on it today it did not appear in the Arduino IDE or even in device manager. It also does not make the sound that normally plays when I connect a USB device to my computer. When I connect it to USB it begins to heat up, which indicates to me that it is running (the small square chip to the bottom left of the USB port heats up immediately, and the processor heats up more slowly).

    I have swapped USB cables, I have tried it on a different computer, and I have no difficulty uploading code to my Teensy 2.0++. I have also rebooted. Does anyone have an idea of what might have happened and how to fix it? I wasn't working with hardware so I don't feel like I fried it with inappropriate voltage. Please let me know if you have any insight. Thank you.

  2. #2
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    7,002
    If you press the button for 15 seconds, it will reset and load the default "blink".
    After that, you can flash it again (press the button)

  3. #3

    No luck!

    Thank you for your response! I plugged it in and held the button for 15 seconds and then hit it again. I did this 3 times, but no results. None of the onboard LEDs blink anymore. I was running [this](https://pastebin.com/TPfPipB1) code, which should be decently inoffensive. It might just be dead, but I can't think of how that code could have done that without some stray jolt of electricity. I have had it lock up when too much memory was allocated, but those times it was just a matter of holding the button while pressing upload. Is there anything else you can think of?

  4. #4
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    7,002
    Did it blink when you released the button after 15seconds? (I think the red LED is brighter after 15seconds for a brief moment)

  5. #5
    No LED action at all, even after holding for 15 seconds.

  6. #6
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    7,002
    Oh... not good

  7. #7
    RIP. Thanks for your help!

  8. #8
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Posts
    22,986
    Before you toss is, maybe try a different cable or measure the VIN voltage? Would be a shame to waste the Teensy if this is just a USB cable or connector problem.

  9. #9
    Yeah, I've tried 3 cables so far, but can you describe from where to where I am measuring voltage? From the 5v pin to ground?

  10. #10
    I've measured the voltage from 5V to ground and it is 5V. From 3.3 to ground it is .11V. I have to step out for a little bit, but thanks for the help.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •