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Thread: How did I kill the Teensy 3.0?

  1. #1
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    Question How did I kill the Teensy 3.0?

    I'm at a loss as to how I killed my Teensy 3.0. I had the Teensy 3.0 connected to a LSM303DLH compass and Ultimate GPS modules. The modules are on a breadboard with a separate regulated 5V power source (verified 5.03V) from a wall wart. I fed the modules with 5.0V and both have LDO regs to feed 3.3V/1.8V to their units and logic is all 3.3V. I connected the ground on Teensy to the ground on the breadboard power supply but power the Teensy from USB. See the photos. Links to the modules: https://www.sparkfun.com/products/10703
    http://www.adafruit.com/products/746

    I tested the GPS and compass separately with the module powered from the Teensy VIN with the Teensy powered by USB. After I connected both to the Teensy at the same time (powered each from the separate power supply), the Teensy stopped responding. So, the power supply connection must have killed the Teensy.

    I get 3.3V from the 2 pins on the Teensy. I do not get [HID 16c0:0478] in the syslog when connecting the Teensy. There was no magic smoke, but the Teensy 3.0 is dead. How did I overcurrent/overvolt the Teensy with just the common grounding and 3.3V connections?
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  2. #2
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    There are various software reasons for the Teensy 3 to not respond to USB, it is not necessarily a hardware problem. Remember, the USB device relies on software to run, it's not hardware USB like in the earlier Arduino boards. Have you disconnected everything and started over with just USB connected to Teensy3 (nothing else) and pressed the bootloader button on the Teensy3 while you have the Arduino environment up on your PC, does the programming window appear? And by the way, are you on Windows, or Mac, or Linux?

  3. #3
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    Quote Originally Posted by JBeale View Post
    There are various software reasons for the Teensy 3 to not respond to USB, it is not necessarily a hardware problem. Remember, the USB device relies on software to run, it's not hardware USB like in the earlier Arduino boards. Have you disconnected everything and started over with just USB connected to Teensy3 (nothing else) and pressed the bootloader button on the Teensy3 while you have the Arduino environment up on your PC, does the programming window appear? And by the way, are you on Windows, or Mac, or Linux?
    Yes, I've done the full Ctl+Alt+unplug. Full shutdown and start up has no change. Nothing happens when Teensy is plugged in, no response from pressing reset button, not recognized by the os as a usb device, nothing. I'm using linux. Cable is known good. It provides power to the Teensy and usb recognizes other devices plugged into this cable after unplugging Teensy. Changing ports and cables has no change. The Teensy is dead.

  4. #4
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    Did you ever see anything in the syslog for the teensy? for other devices? I'm only asking cause I think syslog is done differently by various distros. I seem to remember some logs changing, but unused files remaining.
    Last edited by linuxgeek; 03-29-2013 at 08:46 PM.

  5. #5
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    Quote Originally Posted by linuxgeek View Post
    Did you ever see anything in the syslog for the teensy? for other devices? I'm only asking cause I think syslog is done differently by various distros. I seem to remember some logs changing, but unused files remaining.
    Yes. The last instance occurred a few minutes before the Teensy died. This time corresponds to the last time I plugged it into the usb cable before I powered up the breadboard power supply. No entries since then.

  6. #6
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    Do not try this at home!

    I have the Teensy running now, sort of.

    DO NOT TRY THIS AT HOME!

    If I apply 3.3V to the program pin and program it through the teensy loader it works. Then, I must maintain 3.3V on the reset pin for the Teesny to operate normally. After programming or disconnecting from a power supply, applying and maintaining 3.3V on the reset pin makes the Teensy run normally (runs blinky sketch at least). However, without the 3.3V on the program pin, the Teensy loses serial communication on all (well, I checked Serial1 and Serial2) serial pins.

    My guess is that the LDO built into the mini54tan is fried and applying voltage to its 5.2 and/or 3.2 pins is allowing enough current in for it to operate. I'm trying to learn as much as I can about what caused the failure before frying another Teensy. My best guess now is that static discharge from when I pressed the program button took out the mini54tan's LDO.

    Any ideas or thoughts?

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