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View Full Version : Teensy 3.1 does not show up in Windows Device Manager



tn00364361
03-19-2014, 10:58 AM
I got my black Teensy 3.1 about a month ago, and it worked pretty well, until yesterday. I plug my Teensy into my PC, but it didn't show up in the Device Manager. There's no COM port nor HID device detected. Then I borrowed my friend's green Teensy 3.1 and plug it into my PC, and his Teensy works just fine. Is there any way to verify whether my Teensy is broken?

stevech
03-19-2014, 04:32 PM
One way this can happen is if the last downloaded code is flawed and the CPU runs amok.
The solution is to compile a known good demo program that opens Serial.begin(), then download that by pressing the load button on the Teensy 3.x.

tn00364361
03-20-2014, 09:42 AM
It didn't work...
I first hit Verify to compiled the example code AnalogReadSerial, and hold the reset button to upload. Then the message showed up just like before:

Opening Teensy Loader...
Binary sketch size: 13,224 bytes (of a 262,144 byte maximum)
Estimated memory use: 3,456 bytes (of a 65,536 byte maximum)
Please press the RESET BUTTON on your Teensy to upload your sketch. Auto-reboot only works if the Teensy is running a previous sketch.

Am I doing wrong?

1676


One way this can happen is if the last downloaded code is flawed and the CPU runs amok.
The solution is to compile a known good demo program that opens Serial.begin(), then download that by pressing the load button on the Teensy 3.x.

stevech
03-20-2014, 04:45 PM
What should happen:
You click Verify to compile and build a .hex. Wait a second for that to finish.
Then tap the button on the teensy.You should see the Teensy.exe downloader window - and it should indicate download successful. There can be a 10 second delay before downloading, due to a known issue in Windows, if that's what you are using. This delay is not present most of the time, or after a fresh reboot of windows.

The serial port for interacting is a different USB connection than is temporarily established by the Teensy downloader. That serial port should appear when the downloaded known-good program begins to run.

tn00364361
03-21-2014, 06:51 AM
After the teensy.exe downloader window showed up and finished compiling, I pressed the button in my teensy, but it still remain silent. I tried several ways - tap, press and hold, reconnect then tap - all I got is the same result. I think maybe it's because I just accidentally burned it down without knowing...

PaulStoffregen
03-21-2014, 12:45 PM
Since your computer and USB cable work with another board, and you tried the trick of holding the button while plugging it in, I'd say all signs point to this Teensy being dead.

There are a couple quick voltage measurements that can sometimes identify if a Teensy has died. The 2 easy and obvious ones are VIN (5V) and 3.3V. These will tell if you board is getting USB power and if the 3.3V regulator is working (and nothing on the board is shorted out, causing it to drag down to something like 0.5V).

The other 2 points are Program and Reset. Both should normally be 3.3V. The pushbutton connects to Program and should always cause it to go to zero volts when pressed. The Mini54 chip listens to program and controls reset, which should also be at 3.3V normally and go to zero volts when Program goes low. If Reset is stuck low, it's a pretty good sign one of the chips as failed, but there's no easy way to figure out which one.

You already checked the USB cable, but for anyone finding this thread later, by far the most common cause of this sort of trouble is USB cables meant for cell phone charging. Many of those cables only have the 2 wires for power. They don't even bother putting the 2 data wires inside the cable, which makes it cheaper, but of course nothing can communicate through it.

Markus_L811
03-24-2014, 12:04 PM
The other 2 points are Program and Reset. Both should normally be 3.3V. The pushbutton connects to Program and should always cause it to go to zero volts when pressed. The Mini54 chip listens to program and controls reset, which should also be at 3.3V normally and go to zero volts when Program goes low. If Reset is stuck low, it's a pretty good sign one of the chips as failed, but there's no easy way to figure out which one.

Yep thats happend to mine Teensy 3.1 Reset is low, think he died in the night, in the morning today no connection happend. Bad day

PaulStoffregen
03-24-2014, 12:51 PM
@Markus - please email me directly, paul at pjrc dot com. If you got this directly from PJRC, I'll need your order number. Or if it came from a distributors, we'll need a copy of the invoice or receipt. I'll have a couple more questions. We might be able to get you a replacement.

tn00364361
03-25-2014, 07:41 AM
I've measured those pins:

VIN - 5.01V
3.3V - 3.27V
Program - 3.25V while not pressed, 0.00V while pressed
Reset - always stays 0.11V

Sad :(


There are a couple quick voltage measurements that can sometimes identify if a Teensy has died. The 2 easy and obvious ones are VIN (5V) and 3.3V. These will tell if you board is getting USB power and if the 3.3V regulator is working (and nothing on the board is shorted out, causing it to drag down to something like 0.5V).

The other 2 points are Program and Reset. Both should normally be 3.3V. The pushbutton connects to Program and should always cause it to go to zero volts when pressed. The Mini54 chip listens to program and controls reset, which should also be at 3.3V normally and go to zero volts when Program goes low. If Reset is stuck low, it's a pretty good sign one of the chips as failed, but there's no easy way to figure out which one.

buffalome
09-21-2014, 03:45 PM
There are a couple quick voltage measurements that can sometimes identify if a Teensy has died. The 2 easy and obvious ones are VIN (5V) and 3.3V. These will tell if you board is getting USB power and if the 3.3V regulator is working (and nothing on the board is shorted out, causing it to drag down to something like 0.5V).


Hi,

I have similar problem since the first time I connected teensy to pc. When I connected to pc, my pc tried to find HID driver and led on teensy was blinking. After a while, the led stopped and I got "device unplugged" message from pc. Then I disconnected the usb cable and connect again. The led blink only once and no more. My pc and teensy loader cannot detected it. I tried to change pc and usb cable but it did the same thing.

I tried to find solution then find this thread. I measured VIN and 3.3v but got 1.17v and 0.65v respectively. I really have no idea why it died since the first time. I also tried to troubleshoot (https://www.pjrc.com/teensy/troubleshoot.html) but not success.

So, is this mean my teensy has died since the first use? How can I prevent this situation to happen again?

Thank you,
Kitt


http://www.youtube.com/watch?v=LKRoNs9nsas

shokwaverider
04-26-2015, 01:44 PM
Paul: I have EXACTLY the same issues on 2 boards, but No LED lit. They seem dead and they have only ever been connected to a PC. I have sent you an email with details and both of my order numbers. I also included the HEX code an wiring diagrams.

I would appreciate some help as I am very reluctant to order a 3rd board just to have the same problems.

PaulStoffregen
04-26-2015, 04:21 PM
Paul: I have EXACTLY the same issues on 2 boards, but No LED lit.

I got your email, which has much more information. You're definitely not seeing exactly the same problem as the messages above, which aren't even the same as each other. I know the result is the same: a dead Teensy... but the underlying issues in these 3 messages are vastly different.

Your email has a photo with several wires soldered to the Teensy, which looks like quite a bit more than "only ever been connected to a PC".

I want to help you. I want to get this issue fully resolved. If there's any reason to believe the trouble is due to material or workmanship problems on our part (on a recently purchased board), I'm happy to send you a replacement.

But you've got to participate in finding the solution! When you simultaneously post here and send me private email, and when the two are very different, that really complicates things on my end. Saying here that you've only plugged the Teensy into a USB port, when there's clearly wires soldered in a photo in email really gives me 2 different narratives. Your email talks about soldering, which is completely different than your description here! I'm going to try to do the best I can with the conflicting info I have.....

From your email, you're getting zero volts on the PROGRAM pin and zero volts on the RESET pin, but you have proper 5V and 3.3V power. Clearly that's a very different problem than the power-related issues in message #10 above. Lots of people do lots of awesome creative stuff with Teensy, which can result in a lot of different problems. It's simply not helpful to find a forum topic with related problems and insist they're related, only because they have the same "dead" result. If anything, that's a huge distraction from figuring out what's going wrong.

From your email:



VUSB=5v

3.3v = 3.25v (Both of them)

Reset = 0.00v

Program=0.00v


Zero volts on the PROGRAM pin is almost certainly a sign the pushbutton has failed in a shorted state, or a wire or something else on the board has shorted the PROGRAM line to ground. It's also possible, but very unlikely, that the Mini54 chip could have failed somehow.

PROGRAM is supposed to have a pullup to 3.3V due to the Mini54 chip. When you press the pushbutton, it shorts PROGRAM to ground. That's what instructs the Mini54 to take control of the MK20. When it does that, it drives RESET low. Since you're also seeing RESET stuck low, my guess is the Mini54 is very likely working and doing exactly what it's supposed to do, which is keep RESET low while you continue holding the pushbutton down.

If you're willing to try troubleshooting, the thing to investigate is why PROGRAM is stuck low. My guess is something when wrong during soldering. Or maybe the pushbutton got damaged somehow (typically a physical failure in the button results in an open circuit).

You might also try connecting a fairly low value resistor, like 100 ohms, between PROGRAM and 3.3V. If there's a dead short, PROGRAM will remain at zero volts, even with 30 mA of current. If you have a voltmeter with sensitive mV scale, you might be able to see small changes in the voltage along the path the current takes, which can help suggest where the short might be.

shokwaverider
04-26-2015, 09:35 PM
There is no soldering issue, I have in fact removed all the wires for testing as I was going to send the boards back to you for testing, If you agree I still may do. I will try the tests as you suggest.

I just measured across both unit's switches and they are fine. Pressing them shorts them out as advised.

OK. When I put the resistor on it pulled up the program pin to 3.3v on The Oldest board and it started to work. I powered it on again and left the resistor off, it worked for about 2 or so minutes it stopped working and the Program pin fell low. If I use the resistor permanently it seems to stay working. I am testing it now.

Board 2 the latest one does not revive at all. When the resistor is removed the Program pin goes back to 0v.

shokwaverider
04-26-2015, 10:10 PM
Paul: After all the tests, the board I got Saturday is dead. Cannot seem to be revived.

The Oldest Board if I permanently install a 1k resistor between program and 3.3v it seems to stay working. I am using the Blinking programs. Teesny.exe sees the board when the button is pressed and life seems to be good. Does this mean the New board is Bad?

OK I spoke too soon with the 1k resistor after 5minutes it stopped. I now added the 100ohm resistor back in and it is working again I will let you know if it fails after a while.