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Thread: Teensy 3.2 just randomly died?

  1. #1
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    Teensy 3.2 just randomly died?

    Hey, about a month ago I bought a Teensy 3.2 and shoved it into a project, it was just doing FFT on adc0, reading analog values on some pots on adc1 and reading some button state on a digital input, as well as driving some adressable leds
    When I woke up this morning it was just dead, like, dead dead.
    Took it out of the project and plugged it into my computer, nothing. 5V arrive at the teensy, 3.3V are present on the 3.3V rail.
    It's been working perfectly fine for a month in that exact configuration. It got its power via USB from my computer, the LEDs got power from a seperate supply, common ground, seperate voltage rails.

    They don't just randomly die, do they?
    Any ideas what might be wrong with it?

  2. #2
    Senior Member+ KurtE's Avatar
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    Some of the others who are more the EE types may have more complete answers.

    When you say dead dead. What do you mean? When you plug it in, does your PC see any device? Have you tried some of the hardware debug things like, bring up arduino with a simple sketch like blink, and try to program it? If that does not work, what happens if you hold in the program button as you plug it into your PC? then release it and try to program it?

    If nothing, when it is plugged in to pc, does anything get hot? Have you checked it over looking for any thing obviously wrong? Example on one of my Edison boards, it stopped working, and I could see a pit in one of the IC chips which blew...

    What could go wrong? Not sure how your addressable leds are connected? What type? Many of the leds like neopixels want +5v to drive them, do you have something to convert the voltage? Sometimes an IO pin can try to source to much current, like if the IO pin is shorted, which can cause problems. This can be helped by using a resistor from the IO pin to the device, as a way to limit the current.

    Again hopefully some others may have additional ideas.

  3. #3
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    yeah, sorry for being a bit brief. I was driving SK6812 with the Teensy on 4 pins (3,4,5,6) between the Din pin of the first led and the digital pin of the Teensy was a 470 Ohm resistor.
    The SK6812 prefer 5V signals but they work fine on 3.3V,
    Nothing on it gets hot.
    It doesn't matter what I do with the button, holding it down and plugging it in, pressing it while it is plugged in, different usb ports - the thing just doesn't get detected, not even showing up in the device manager.
    It did not break while plugging it in either, it was connected all night (like for the past month).
    When i pressed the button (simple tactile switch) this morning though, it did not power up the leds like I expected, it just did nothing.

  4. #4
    Senior Member PaulStoffregen's Avatar
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    Have you tried disconnecting everything from the Teensy?

  5. #5
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    Yes, i pulled it out of the project and plugged it into a different µUSB lead on my desk

  6. #6
    Senior Member PaulStoffregen's Avatar
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    There's a simple way to check if the MKL02 chip is still alive. You need to monitor the voltage on the Program pin and Reset pin (bottom side, "R" pad). Normally, both are supposed to be 3.3V due to weak pullups. When you press the button, it shorts Program to ground. If the MKL02 chip is alive, it's supposed to be watching and it will pull the Reset signal to ground while you're holding Program low. This behavior can at least verify if that chip is still alive.

    Very hard to know what happened here, even with this sort of diagnostic. These boards don't just die for no reason. There's always some reason, but after the hardware is damaged by some unknown cause, it can be difficult or impossible to figure out what really happened.

  7. #7
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    The program pin pulls low when I press the button, the Reset signal stays high when I press the button, so I suppose the MKL02 chip is dead?

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