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Thread: Cannot connect PC to Teensy

  1. #1
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    Cannot connect PC to Teensy

    I've been using Duemilanove and Uno to program Atmel 328-PU chips for the purpose of creating test equipment for many years. I program on a very basic level due to not knowing much about computers, processors, or microcontrollers. I'm currently attempting to start working with Teensy for the first time but can't get started because my teensy and PC won't connect. When I check port assignments under Tools, no ports show up like with Arduino. What am I missing? I loaded Teensyduino twice with no improvement. Don't know what else to do.

  2. #2
    Senior Member+ KurtE's Avatar
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    Most of the Teensy boards ship with NO usb type of USB, so they don't initially show up.

    So what I will normally do is:

    Load up Arduino IDE, Select the board type of which teensy you have. Set USB Type=Serial both of these should be under the tools menu.

    Now load a simple program like the example: blink

    Now do an arduino verify/compile command and it should run the build and brings up the Teensy app...
    Now click the program button on your new teensy.

    You should hopefully see the teensy app connect to it, and program it, with the blink program and the pc should then assign it a Serial port number (depending which OS you are running on...)

  3. #3
    Senior Member PaulStoffregen's Avatar
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    Are you using Windows? Does your PC normally make a chime sound when a USB device is plugged or unplugged?

    Even if Teensy is blank (they are all supposed to ship with a LED blink program which shows up as RawHID) you should get a HID device (not serial, no COM port) after pressing the pushbutton (and the orange LED blinking should stop).

    If you get no USB devices detected at all, and no chime sounds on a Windows PC which normally chimes, that's a sure sign you have a charge-only USB cable. They're incredibly common, sold with all sorts of products which use USB to recharge batteries. These cables have only 2 wires for power and are completely missing the 2 wires for data.

  4. #4
    Senior Member PaulStoffregen's Avatar
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    Also, if you have Teensy 4.0 or 4.1 (can't tell which one you have), those newer boards have a restore process which is triggered by holding the button for 15 seconds. It can't do anything to fix a bad USB cable. But if you're wondering whether the hardware is good, seeing it go though that process can at least confirm the hardware is working.

    But if it's never communicated with your PC, and you see the orange LED slowly blinking when you plug it in, and the orange LED stops when you press the button, that's a pretty sure sign your Teensy is good and the problem is simply a charge only cable.

  5. #5
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    Can't connect PC to Teensy

    KurtE and PaulSoffregen - thanks so much to both of you for your responses. I tried your test, KurtE and nothing happened. When I disconnect the cable there is no chime so I believe Paul is correct. I'll have to track down an appropriate cable so I'll do that for now. Thanks so much guys!!!! I'll let you know how that works out.

  6. #6
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    I'm using Teensy 4.1.

  7. #7
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    I'm up and running!!! I happened to have another cable at hand which is good. Thank you gentlemen very much!!!

  8. #8
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    Quote Originally Posted by PaulStoffregen View Post
    Are you using Windows? Does your PC normally make a chime sound when a USB device is plugged or unplugged?

    Even if Teensy is blank (they are all supposed to ship with a LED blink program which shows up as RawHID) you should get a HID device (not serial, no COM port) after pressing the pushbutton (and the orange LED blinking should stop).
    I have a similar problem, and this thread helped fix it. I'm using windows7 x64, Teensy3.2. I have programmed several successfully, then suddenly had trouble. When I plugged it in, blink runs, and I see it has a port "hid#vid_16...(Teensy3.2)".. assigned. I click upload, then it stops working. Next time I try, it no longer has a port. I can't load anything, and it does not run blink or anything else. I managed to break two of them before finding this thread, and followed Kurt's method. I realized I had not pressed the button, and did not see it referenced as USB serial port, just the HID generic port. With a new teensy, compile blink, pressing the button assigns a USB serial com port (COM38 Serial) , and I can program it without problems. I found that just plugging it in and pressing the button does not work, I have to compile first and wait for the Reboot window to open.
    So Paul, it would be a great help if you could spell out a few details of what is happening here, why does pushing the button not start the USB serial driver if the Reboot window is not open?
    How one should "normally" proceed in the first few steps to reliably start uploading, assuming a good cable and proper drivers are loaded? I see different results depending on the sequence of actions, starting the IDE before/after plugging in, etc. I have not found a simple set of instructions to start this correctly, just explanations for when things go wrong.
    Also, I now have two teensy3.2 that don't work, can't be programmed, nothing broken but somehow I need to get back to the HID#vid port or reboot to serial com port. How to proceed?

  9. #9
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    Quote Originally Posted by Knoonan View Post
    How one should "normally" proceed in the first few steps to reliably start uploading, assuming a good cable and proper drivers are loaded?
    @PaulStoffregen
    Ok, newbie mistake, sorry. I found the page https://www.pjrc.com/teensy/first_use.html very helpful. But still some confusion.
    I still have two teensy3.2 that don't talk, and I don't understand why. I think I tried to program my user code while it was running blink, not Halfkay, did not press the button.
    Why does that brick the Halkay program? Does Halfkay run the serial IO to make the system recognize the port connection?

    How can I get Halkay back if the system doesn't recognize that the teensy is plugged in?

  10. #10
    Senior Member+ KurtE's Avatar
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    Sorry, I am not Paul ...

    But I thought I would mention a couple of things:

    That page: https://www.pjrc.com/teensy/first_use.html is very much oriented toward the original Teensy 1 and 2 boards that were AVR based.
    Halfkey stuff again is for the old AVR stuff (which is still old)

    Paul - would be good if the website had a few changes where pages like this are marked as such (please).

    With t3.2 you can not overwrite the bootloader, it is held in a different chip.

    As for things to try, again there is the stuff on the page: https://www.pjrc.com/teensy/troubleshoot.html

    Also unclear from your description, if these board are untouched or if you soldered anything to them. If anything connected, I would try with removing everything if possible... (I don't mean to unsolder pins or the like), but cables uplug except usb... Or if in breadboard remove...

    Also if you modified them, like cut the VIN/VUSB, then you need to make they have power...

  11. #11
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    I have ten of the boards, mostly untouched. I have bricked two of them, and correctly programed two of them. I will study the link you sent, have not seen that.
    2 have the power link cut, but I have a switch in my circuit to handle that. mostly I am exploring this issue with virgin boards , not connected to anything else.
    Thanks KurtE,
    Kent

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