View Full Version : Teensy3 stopped responding

12-11-2012, 06:59 AM
Hi, I just got my Teensy3. It was working really nicely and had it hooked up to a 3.3v IMU, and everything seemed to be running smoothly.
Then suddenly everything stopped.

Now when I plug in the teensy3 the system does not recognize it at all, and it appears as dead as a dodo.

Clicking the button does nothing and the Teensy downloader does not respond to it.

Is there anyway to diagnose what happened? Can the bootloader get corrupted? can it be fixed? or is it just a very sensitive device? I only had it a few days!


12-11-2012, 05:37 PM
does the DC-DC convertor still work ? (do you get 3.3V on the pin after pin 23 when powered from USB, when powered from vin)

12-11-2012, 06:11 PM
No I get about 0.7v on the 3.3v pin, and the CPU gets quite warm.

12-12-2012, 12:27 PM
If you completely disconnect the Teensy from the rest of your system and power it only by the USB, what do you get on the 3.3 volt pin?

If it returns to 3.3 volts, then the Teensy is probably fine and the external circuitry is drawing too much power or connected incorrectly.

If it's still 0.7 volts on the 3.3 volt pin with nothing else connected, then the unpleasant news is something went terribly wrong and destroyed the Teensy.

12-12-2012, 09:29 PM
Hmm well I get 0.7v when nothing else is connected. So I guess it is fried :( I wonder why? Nothing else on the board was damaged, the IMU still works and it is 3.3v as well, and the total current draw was probably around 10-20ms.

Oh well, so much for me testing out an ARM. I have had a regular Teensy doing the same thing for a while and no problems there. This chip mist be way more sensitive or fragile.

12-13-2012, 01:08 AM
[QUOTE= I have had a regular Teensy doing the same thing for a while and no problems there. This chip mist be way more sensitive or fragile.[/QUOTE]
or the 3.3v Teensy 3 didnt like the 5v that drove the Teensy 2 ;-)

12-13-2012, 02:55 AM
It wasn't being powered by 5v, it was powered from the USB. and the IMU was 3.3v also.

12-13-2012, 08:28 PM
If you want to continue discussing *why* this happened, with any hope of ever gaining any understanding, you're going to have to be much more specific about exactly how you connected everything. A photo of the actual wiring would be a start. Which IMU product you used would also be a good piece of information, which I couldn't see above. Any other parts you used, again, should be clearly identified (unless you want everyone reading to keep guessing in the dark). Small details matter.

The USB voltage is 5 volts. Teensy 3.0 has a regulator on the chip which converts it to 3.3 volts. The "VIN" pin provides the 5 volts directly from the USB. If you connect that to any other pin on Teensy 3.0, damage is likely. When designing 3.0, I debated whether to provide a VIN pin at all, because it does give you a path to destroying the board if you're not careful. But there are so many projects that need the direct 5 volts. In fact, FreeIMU and others have a 3.3 volt regulator but need 5 volts input.

So, if your purpose here is to say Teensy 3.0 is fragile, there is indeed a 5 volt output meant for powering other stuff (or providing 3.7 to 5.5 volts from a battery or other power source, to the power the board, if the jumper pads are cut apart) which can destroy the board if accidentally shorted to other pins. Teensy 2.0 doesn't have anything like that, so it is more robust.

If your purpose is to meaningfully discuss what went wrong, causing your Teensy 3.0 to be destroyed, so far you've given so little specific information that nobody can know. Please, if you're going to continue this conversation, at least post a photo of your actual wiring, and specific info about the exact components you used.

12-14-2012, 01:20 AM
Unfortunately I cannot photo it as I dismantled it to test the individual components.

The Teensy3 has female headers soldered in (like the arduino). The IMU and motor control board are on a separate proto board, the connections are via male to make proto wires.

There was no connection the the Vin pin so no chance of shorting (part of why I use female headers on the Teensy). The IMU is this one from Pololu http://www.pololu.com/catalog/product/1268,
as it as dual 5v and 3.3v I connected the Teensy 3.3v to the Vdd pin if the IMU. Vin is left unconnected so no 5v there. In fact there is no 5v anywhere on the protoboard.

The motor controller is this one http://www.pololu.com/catalog/product/1213 The 12v and motor connections are made directly to the screw terminals on the board so do not go anywhere near the proto board or Teensy, and the 12v is totally isolated from the protoboard. The only connections from the Teensy3 to the motor driver board are IN1, IN2, D2/PWM and ground. Vdd is connected to the 3.3v rail only to pull up the various enable pins.

The motors are these http://www.pololu.com/catalog/product/1443 and the magnetic encoders are connected to 3.3v and a couple of Teensy pins to count the quadrature pulses.

The total draw on the 3.3v would be 10mA for the IMU and 10Ma each for the encoders so no more the 30Ma.

As the Teensy is not mounted on the protoboard, and neither are the motor connections, I see little possibility of shorts, and there is no 5V on the system at all, other than on the Teensy3 itself.

I tested all the other components and they still work fine, if there had been a catastrophic short of 12v then the IMU and motor controller would have fried.

So I am not sure why the Teensy3 died, hence the reason for me saying it seems a little "fragile". In my experience the IMUs are the first to go as they seem extremely fragile and sensitive to higher voltages and spikes.

If the internal 3.3v converter died, is it possible I could power it from an external 3.3v connected to the 3.3v pin if I isolate the USB 5v?

I would like to know why it died, before I get another, so I can decide where I can use one. For now I'll go back to using my Teensy2++.