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Thread: Can't program Teensy LC after flashing

  1. #1
    Junior Member
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    Nov 2014
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    Can't program Teensy LC after flashing

    So I'm prepared to chalk this one up to me experimenting with dangerous magic. But, I was under the impression this couldn't happen. I am experimenting with the Mecrisp Stellaris Forth compiler on several platforms. I noted from their documentation that it should work with a Teensy 3. So I compiled the HEX file, plugged in my teensy, opened the HEX file in the app, and pressed the button on the Teensy.

    It didn't seem to work. Then I turned it over and realized it's a Teensy LC, not a 3 (sorry, my fault, should have been more observant). It's a different uC, and the Mecrisp project is specifically building for the MK20DX256. Oh well, figured I'd just put back a "blink" firmware and move on to some other board for playing with mecrisp.

    But now I can't write anything to it. I've tried it on my Linux box and my Mac -- whether I press the program button before plugging it in, or press it when the teensy loader pops up, it doesn't seem to matter.

    Is it possible to program a HEX file with the Teensy loader that will brick the board? I've seen a couple threads on here about bricking it by going around the bootloader firmware, but now I'm concerned I found a way to kill it.

    Is there any way to recover my Teensy LC?

  2. #2
    Senior Member PaulStoffregen's Avatar
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    Nov 2012
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    Could you email this hex file to me? paul at pjrc dot com I'll program it onto a Teensy LC here and see what happens.

    It definitely is possible to program hex files that do wrong USB stuff. That's why we have the recovery process where you hold the button when plugging in the cable, to prevent the wrong code from getting a chance to run.

    https://www.pjrc.com/teensy/troubleshoot.html

  3. #3
    Junior Member
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    Nov 2014
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    Quote Originally Posted by PaulStoffregen View Post
    Could you email this hex file to me? paul at pjrc dot com I'll program it onto a Teensy LC here and see what happens.

    It definitely is possible to program hex files that do wrong USB stuff. That's why we have the recovery process where you hold the button when plugging in the cable, to prevent the wrong code from getting a chance to run.

    https://www.pjrc.com/teensy/troubleshoot.html
    Email sent -- ultimately, if it's borked, I'll just order some more. Not that I *don't* want to know what happened :-). Thanks Paul!

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