Teensy not found

C

ChrisCurl

Active member
I am using Arduino 2.3.2, Teensy 1.59.0, Debian 12 Linux, with a Teensy 4.0 I recently received (from my daughter - she bought in on Amazon).

I get this message, and I don't know how to fix it.

Teensy should be selected from "teensy ports" rather
than "Serial ports" in Arduino's Tools > Port menu

The only port shown is /dev/ttyS0

It also says to press the PROGRAM MODE BUTTON, which I did, and nothing.

Is my Teensy dead?

Please help
 
Last edited:
The most common problem for Teensy not detected is use of a power-only cable. They're incredibly common in drawers of leftover USB cables.

On Linux, the 2nd most common problem is not having the udev rules file installed. But lacking udev rules usually results in inability to access, or strange problems with usage. Not detected at all happens with a bad cable.


ChrisCurl said:
Is my Teensy dead?
Click to expand...

Every brand new Teensy ships with the LED blink program loaded. If it hasn't been programmed yet, you should see the orange LED near pin 13 blinking slowly. If someone has programmed it, of course it will do whatever their program does.

When you press the pushbutton, the user program stops running and Teensy goes into bootloader mode. If the orange LED was blinking, it should stop. if you hold the pushbutton, no LEDs should light as long as you keep pressing. When you release it, you should see the red LED near the USB connector turn on. This change in LED behavior after pressing the pushbutton is a strong confirmation your Teensy is still working.

The red LED does a slow steady blink if absolutely no USB communication (not even your PC detecting the USB device) has been heard while in bootloader mode. If you see that on the red LED, it's a sure confirmation you have a power-only cable.
 
I should have mentioned that I also have a RPI Pico and, with it connected to the same cable, the Pico shows up as (/dev/ttyACM0), and the Serial Monitor comes up and behaves as expected.

I'll try a different cable anyway. The red LED does not turn on after pressing the PROGRAM MODE button.
 
Something is wrong. The red LED should turn on after pressing the Program button.

But please understand Teensy uses HID protocol in programming mode, not Serial. So if you look only for a /dev/ttyACM device, you'll miss Teensy when it's using non-Serial protocols.

On Linux, best to run "tail -f /var/log/syslog" so you can see the kernel's messages about detecting USB devices.
 
It must be bricked. I tried a different cable that I know to be good (it also worked exatly as expected with the Pico), and still nothing from the Teensy. Not even the red LED when I release the program-mode button.

Time to buy a new Teensy I guess. :(

BTW, it turns out my system doesn't have a /var/log/syslog; it is Debian-12 (bookworm). Instead, it has a program "journalctl -f" program that appears to have the same behavior.
 
Last edited:
So I measured the voltages on the pins when plugged into the USB port. The voltage between 5V <--> GND has 5.18V. The voltage betwen 3V <--> GND jumps around in the low mV range.
 
So I too am having this problem.

I have a 3.2 which was working fine on that project but I wanted to swap it out with a 4.0 from another project from a different project which was also running fine. I connect the 3.2 to my computer and it recognizes it but it will not allow me to select the Teensy Port. I cut all the wires from each, removed all the wires & soldering from the 4.0 in preparation to re-wire into my 3.2 project. Same problem with the 4.0, it won't allow me to select the port at all. I doesn't recognize that its attached to my computer.

  • I am using the same serial cable I've used for dozens of projects. I tried a new cable, which works with other boards but not the 3.2 nor the 4.0. I tried all my USB ports, nada.
  • I am on Windows 11 Home
  • I am using Arduino IDE 2.3.2 and have Teensy Loader 1.59 installed
  • I have uninstalled TL 1.59 and reinstalled it
  • I have uninstalled the boards and reinstalled the boards
  • I have the USB Port set to Serial
  • I have pushed the Program Mode button many times
  • I have rebooted my computer many times.
  • I have tried to reset the 4.0 board by holding down the reset button for 15 seconds until the red light appears, it never lights
  • I have done all of the above on a second computer I have and nada
I'm at a loss of what to do next.
  • Teensy4.png
 
TopHatRaver said:
I doesn't recognize that its attached to my computer.
Click to expand...
Well, that could mean 2 things: either your USB cable is broken or your Teensy is dead.
With your Teensy connected to your PC with the USB cable, can you measure what the voltage is on Teensy 4.0 pin "Vin" (should be ~5Vdc) and pin"3.3V" (should be ~3V3) ? Arduino IDE running or not, is not relevant for this voltage measurement.

Paul
 
You must log in or register to reply here.
Back
Top