Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 4 of 4

Thread: Teensy 3.5 not recognized

  1. #1
    Junior Member
    Join Date
    Nov 2019

    Teensy 3.5 not recognized

    Good morning

    I order a Teensy 3.5 a few months ago and finally got around to using it. I followed the installation manual to the letter and the Teensy loader application does not recognize my board, even when I press the button on the T3.5.

    The pre-loaded Blink program runs when I plug the board into USB (or power from 3.3v power supply). In Arduino, I try to upload a simple Hello World or Blink progam, wait a few seconds, then press the button on the T3.5. Blinking LED goes out and nothing else happens - the board is not recognized.

    I've swapped through four different USB cables, all known to be data-capable (one of which is brand new). I've performed combinations of reinstalling Arduino, rebooting and even removing the battery from my computer and repeating process again. Same result.

    Board is from PJRC straight out of the package. I soldered header pins to the board and was careful not to overheat any part of the board.

    Teensy 3.5
    Arduino 1.8.10
    Teensyduino 1.48
    Windows 10 (1803 Build 17134.1040)
    Screenshot attached of Arduino settings
    Picture attached of soldering

    Could there be an issue with this board? Any recommendations?

    Thanks for the help.


    Click image for larger version. 

Name:	Screenshot (3).png 
Views:	16 
Size:	70.4 KB 
ID:	18143Click image for larger version. 

Name:	20191108_094021.jpg 
Views:	18 
Size:	192.8 KB 
ID:	18144

  2. #2
    Junior Member
    Join Date
    Nov 2019
    Update: I figured out the problem and it was my USB cable. WOW!

    I can't believe that of my 4 cables (some of which I could have sworn came with an external harddrive), none of them had D+ and D- wires. The Teensy installation troubleshooting mentions to check the cable but perhaps this can be updated to make it extra clear. Verification of the cable is mandatory because I'll bet 90% of the population doesn't realize their cables at home are power-only!

    I used a micro-USB breakout to give better access to the small end of the cable. Then tested for continuity using a multimeter to determine which cables had all four wires. Simple. The technique is described here:

    So far, the Teensy is working great. Thanks for the great product!


  3. #3
    Senior Member+ defragster's Avatar
    Join Date
    Feb 2015
    Four out of FOUR is pretty amazing to have no data lines! With note of 4 tested I skipped the boilerplate 'Make sure you have a GOOD USB Data cable' …

  4. #4
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Quote Originally Posted by david337 View Post
    The Teensy installation troubleshooting mentions to check the cable but perhaps this can be updated to make it extra clear.
    Any ideas how we could make it more noticeable?

    On Teensy 4.0 we added a red LED, mainly motivated by the need to show a distinctive blink with these charge-only cables.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts