Teensy 4.0 won't connect to PC

enxa

Member
Hi all,

I have a Teensy 4.0 which, as far as I know, has no code on it yet as I am yet to upload anything to it.

However, when I do plug it into my PC, the LED simply blinks twice every few seconds and the pushbutton doesn't seem to do anything.

I've tried a few different USB cables and different USB ports on my PC too, but no luck.
Windows doesn't seem to recognise it at all.

I've tried searching around and can't seem to find much information for 2 blinks

Could the board be dead?

Thanks in advance
 
Just to add some more info,

I've checked the cables I bought from amazon, and they are listed as being data cables too.

If I load up the Blink example sketch and verify that, the teensy loader pops up

But it never recognises me pressing the button

And pressing the button repeatedly does seem to stop the LED from flashing
 
The button is a Programming button.
The Teensy ships with the blink program installed.
If it blinks when powered up from new then you know it is working.
 
Hi,

Thanks for your reply

I understand this, but I can't get windows to recognise it at all, nor the Arduino software

I was just using the blink sketch as an example, this is not what I want on the teensy. I want to upload my own sketch.

Thanks
 
I've checked the cables I bought from amazon, and they are listed as being data cables too.

As seen on this forum, the most common cause of the Teensy not being recognized is cable problems. Even though you checked the listing, trying a different cable might still prove beneficial.

Mark J Culross
KD5RXT
 
As noted, the Button puts the Teensy into Program mode.

In this mode the PC generally won't recognize this unique mode.

Having the IDE open and doing a Verify to get a working HEX file will open the Teensy Loader that is prepared to connect to the Teensy in Program mode.

Teensy Loader has: ' Help / Verbose Info ' menu option that will open a window indicating when a Teensy is seen and messages transferred.

In this condition plugging a Teensy in and pressing the Button should result in the 'Verbose' window showing messages.

If nothing shows in that window the cable or USB port are not performing as expected to connect to the computer as required.

Assuming the Teensy still running factory blink when plugged in?

With Teensy Loader open as above: Try unplugging the Teensy and Hold the Button while plugging in the USB cable and release the button a second later. Any response?
 
Hi, thanks for your response.

Yes it is still running the factory blink, I've not managed to upload anything to the teensy yet.

Unplugging the teensy, holding the button and re-plugging in does not provide a response in the logs.

But the verbose window does show the following when trying to upload the code:


Code:
15:50:43.390 (post_compile 1): Begin, version=1.57, high-res time
15:50:43.613 (loader): Teensy Loader 1.57, begin program
15:50:43.707 (loader): File "C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\Blink.ino.hex", 20480 bytes
15:50:43.709 (loader): File "Blink.ino.hex". 20480 bytes
15:50:43.726 (loader): Listening for remote control on port 3149
15:50:43.726 (loader): initialized, showing main window
15:50:43.800 (loader): remote connection 1280 opened
15:50:43.801 (loader): remote cmd from 1280: "comment: Teensyduino 1.57 - WINDOWS (teensy_post_compile)"
15:50:43.802 (post_compile 1): Sending command: comment: Teensyduino 1.57 - WINDOWS (teensy_post_compile)
15:50:43.802 (loader): remote cmd from 1280: "status"
15:50:43.804 (loader): HID/win32:  vid:1852 pid:7022 ver:0001  usb:0/140000/0/C/C
15:50:43.806 (loader): HID/win32:  vid:046D pid:C332 ver:0302  usb:1C0002/0/0/4/4/3/4
15:50:43.806 (loader): HID/win32:  vid:05AC pid:024F ver:0121  usb:1C0002/0/0/4/4/4/5
15:50:43.807 (loader): HID/win32:  vid:046D pid:C332 ver:0302  usb:1C0002/0/0/4/4/3/4
15:50:43.808 (loader): HID/win32:  vid:05AC pid:024F ver:0121  usb:1C0002/0/0/4/4/4/5
15:50:43.808 (loader): HID/win32:  vid:046D pid:C332 ver:0302  usb:1C0002/0/0/4/4/3/4
15:50:43.809 (loader): HID/win32:  vid:04D8 pid:00DF ver:0101  usb:0/140000/0/D/F
15:50:43.810 (loader): HID/win32:  vid:05AC pid:024F ver:0121  usb:1C0002/0/0/4/4/4/5
15:50:43.810 (loader): HID/win32:  vid:046D pid:C332 ver:0302  usb:1C0002/0/0/4/4/3/4
15:50:43.813 (loader): remote cmd from 1280: "dir:C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\"
15:50:43.813 (post_compile 1): Status: 1, 0, 0, 0, 0, 0, C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\, Blink.ino.hex
15:50:43.813 (post_compile 1): Sending command: dir:C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\
15:50:43.814 (post_compile 1): Sending command: file:Blink.ino.hex
15:50:43.814 (loader): remote cmd from 1280: "file:Blink.ino.hex"
15:50:43.820 (loader): File "C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\Blink.ino.hex", 20480 bytes
15:50:43.821 (loader): File "Blink.ino.hex". 20480 bytes
15:50:43.825 (loader): remote cmd from 1280: "status"
15:50:43.830 (post_compile 1): Status: 1, 0, 0, 0, 0, 0, C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\, Blink.ino.hex
15:50:43.830 (post_compile 1): Sending command: auto:on
15:50:43.830 (loader): remote cmd from 1280: "auto:on"
15:50:43.831 (post_compile 1): Disconnect
15:50:43.843 (loader): remote connection 1280 closed
15:50:46.005 (loader): Verbose Info event
15:51:03.206 (loader): file changed
15:51:03.213 (loader): File "C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\Blink.ino.hex", 20480 bytes
15:51:03.216 (loader): File "Blink.ino.hex". 20480 bytes
15:51:03.216 (post_compile 2): Begin, version=1.57, high-res time
15:51:03.224 (loader): remote connection 1344 opened
15:51:03.227 (post_compile 2): Sending command: comment: Teensyduino 1.57 - WINDOWS (teensy_post_compile)
15:51:03.229 (loader): remote cmd from 1344: "comment: Teensyduino 1.57 - WINDOWS (teensy_post_compile)"
15:51:03.234 (loader): remote cmd from 1344: "status"
15:51:03.240 (loader): remote cmd from 1344: "dir:C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\"
15:51:03.241 (post_compile 2): Status: 1, 1, 0, 0, 0, 0, C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\, Blink.ino.hex
15:51:03.241 (post_compile 2): Sending command: dir:C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\
15:51:03.244 (loader): remote cmd from 1344: "file:Blink.ino.hex"
15:51:03.244 (post_compile 2): Sending command: file:Blink.ino.hex
15:51:03.252 (loader): File "C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\Blink.ino.hex", 20480 bytes
15:51:03.257 (loader): File "Blink.ino.hex". 20480 bytes
15:51:03.265 (loader): remote cmd from 1344: "status"
15:51:03.273 (post_compile 2): Status: 1, 1, 0, 0, 0, 0, C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\, Blink.ino.hex
15:51:03.273 (post_compile 2): Disconnect
15:51:03.298 (loader): remote connection 1344 closed
15:51:03.369 (post_compile 3): Begin, version=1.57, high-res time
15:51:03.370 (loader): remote connection 1344 opened
15:51:03.374 (loader): remote cmd from 1344: "comment: Teensyduino 1.57 - WINDOWS (teensy_post_compile)"
15:51:03.375 (post_compile 3): Sending command: comment: Teensyduino 1.57 - WINDOWS (teensy_post_compile)
15:51:03.379 (loader): remote cmd from 1344: "status"
15:51:03.386 (loader): remote cmd from 1344: "dir:C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\"
15:51:03.387 (post_compile 3): Status: 1, 1, 0, 0, 0, 0, C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\, Blink.ino.hex
15:51:03.387 (post_compile 3): Sending command: dir:C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\
15:51:03.391 (post_compile 3): Sending command: file:Blink.ino.hex
15:51:03.391 (loader): remote cmd from 1344: "file:Blink.ino.hex"
15:51:03.400 (loader): File "C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\Blink.ino.hex", 20480 bytes
15:51:03.404 (loader): File "Blink.ino.hex". 20480 bytes
15:51:03.412 (loader): remote cmd from 1344: "status"
15:51:03.420 (post_compile 3): Status: 1, 1, 0, 0, 0, 0, C:\Users\enxa\AppData\Local\Temp\arduino_build_608556\, Blink.ino.hex
15:51:03.420 (post_compile 3): Disconnect
15:51:03.442 (loader): remote connection 1344 closed
15:51:03.442 (post_compile 4): Running teensy_reboot: "C:\Program Files (x86)\Arduino\hardware\teensy\..\tools\teensy_reboot.exe" teensy_reboot.exe "-board=TEENSY40" "-port=COM3" "-portlabel=COM3" "-portprotocol=serial"
15:51:03.447 (loader): remote connection 1344 opened
15:51:03.465 (reboot 5): Begin, version=1.57, high-res time
15:51:03.465 (reboot 5): location = COM3
15:51:03.465 (reboot 5): portlabel = COM3
15:51:03.465 (reboot 5): Serial device COM3 will be tried first
15:51:03.465 (reboot 5): portprotocol = serial
15:51:03.465 (reboot 5): LoadLibrary cfgmgr32 ok
15:51:03.465 (reboot 5): LoadLibrary ntdll ok
15:51:03.466 (reboot 5): nothing new, skipping HID & Ports enum
15:51:03.466 (reboot 5): usb scan found 0 devices
15:51:03.469 (loader): remote connection 1424 opened
15:51:03.475 (reboot 5): Disconnect
15:51:03.490 (loader): remote connection 1424 closed
15:51:03.495 (loader): remote connection 1344 closed


Seems like it just can't find any usb devices?
 
The IDE prints the following:

Code:
Memory Usage on Teensy 4.0:
  FLASH: code:8820, data:3048, headers:8608   free for files:2011140
   RAM1: variables:3776, code:7120, padding:25648   free for local variables:487744
   RAM2: variables:16512  free for malloc/new:507776
No Teensy boards were found on any USB ports of your computer.
Please press the PROGRAM MODE BUTTON on your Teensy to upload your sketch.

And also, when compiling, the flashing on the teensy stops, so it must know it's there?!
 
And also, when compiling, the flashing on the teensy stops, so it must know it's there?!

Well that really is a very strange result, because everything else points to no USB communication happening at all. The verbose info in msg #7 shows no USB activity which could be from any Teensy. From verbose info, nothing actually occurred on your PC that could have told Teensy to stop running the blink program.

Just to be clear, the LED absolutely is supposed to stop blinking if you press the pushbutton on Teensy.

Since you're using Windows, first confirm whether your system makes chime sounds when you plug and unplug USB devices. If not, I'm sure there's some way to turn those sounds on. Maybe people who use Windows could comment. Or it's probably findable with Google or other search.

When you first plug in the cable, you should hear the USB connect chime. When you press the button on Teensy, you should hear the USB disconnect chime. And when you release it, you should hear the USB connect chime again. You could also watch Windows Device Manager, but it's tricky since Teensy appears as Human Interface Device in some modes and Ports in others. The chime sounds are so much simpler.

Charge-only cables are by far the most common problem. Dodgy cables that work with 12 Mbit/sec boards like Arduino Zero but fail at 480 Mbit/sec Teensy 4 are rare, but we've seen them occasionally on this forum. Except that you've said the LED stops blinking, everything else looks exactly like a charge only cable without data wires. It's probably time to go find a known-good cable. I should mention, we've seen the charge-only cable problem over and over on this forum. Sometimes people have found 4 or even 5 leftover cables in a drawer which all turned out to be charge only. They're incredibly common. Make sure you find a known good cable.
 
@enxa: you may want to download USBtreeview.
That tool will clearly show whether your Teensy is connected over USB.

With the Blink sketch running:
UTV1.png

When you press the Program button:
UTV2.png

A long shot: did you insert the USB cable far enough into the Teensy USB connector? I am able to insert the USB cable half way such that the Blink sketch is running but not showing on USBtreeview.
You should insert the USB cable gentle but not too gentle...

Paul
 
Just as an update, I ordered a new Teensy 4.0, plugged it in, and it all worked fine first time.
Must have been dead for some reason. Will try and work out why, but my problem is solved!

Thanks everyone for the help
 
Hello,
got similar issue,
yesterday evening i was programming the T4 and today morning it does not enumerate in PC as com port (I was using double serial).
What i have noticed was that voltage on 3V3 dropped to atound 1,2 V after some seconds and the MXRT chip gets pretty hot :(
The reset to blink program does not happen as the voltage drops prior 15 s.

It does the same thing whether its seated on breadboard or not so perhaps i have damaged the chip by static electricity as i was carrying it in my plastic notebook bag this morning :) i mean :(
 
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