Teensy 4.0 Not flashing

C

clcarey

Member
Hello,

I have a couple of teensy 4.0s that I am attempting to flash with new software. My computer fails to see them in bootloading mode.
My computer can see the teensies until they enter bootloading mode at which point it fails to recognize them. The LED continuously blinks red which from other posts seems to indicate that no USB communication is happening whatsoever.
I believe this is a computer issue, particularly given a recent microsoft update. Any thoughts on settings etc that may have caused this, or any troubleshooting steps.

The attached photos show zadig's interaction with a teensy before and after pressing the teensy button (using zadig to view the interface not attempting to install a usb driver)
 

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Can the Teensy Loader see it? That looks like the bootloader USB ID.
The RED LED by USB goes on with button push?
 
As far as I can tell no the teensy loader cant see it, as it my interface says no teensy detected.
And yes the red LED by the USB blinks after pressing (off while held) but still doesnt connect.
For additional reference I am using the platformio plugin for clion as my interface
 

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Could you install the Arduino IDE, preferably version 1.18.19, and then Teensyduino.
Then see if you can program the Teensy's.
A lot of people seem to have problems with PlatformIO.
Personally I use Visual Micro with Microsoft Visual Studio. So much better than the Arduino IDE and without the problems that PlatformIO brings.
 
The most common problem is power only USB cables. They're incredibly common in drawers & boxes of leftover cables. We've had people report "tried another" cable only to find 5 of them in a leftovers box were all from some cheap products that used USB for power only!

Before you waste a lot of time on software and drivers, please make sure you're using a cable which actually has the wires for data.

Also please be aware Teensy uses HID protocol by default and always in bootloader mode. All 3 operating systems come with HID drivers by default. No special driver or device settings are needed. You absolutely should NOT install any libusb and WinUSB drivers associated with Teensy's ID numbers! Doing so could cause Windows to be unable to use it normally with the normal HID driver.
 
I am certain that the cable I am using works, as it is epoxied in place and has worked many times before on this computer, and is working on other computers.
I have not installed any other USB driver, I just used zadig as it is the easiest method I am aware of to view information regarding USB ports.
Are there other troubleshooting steps I can explore, while other computers work I can't exactly borrow one indefinitely for this project.
 
clcarey said:
red LED by the USB blinks after pressing
Click to expand...
Paul can confirm - but this blinking says the Device is not finding a Host.
It should go to Solid Red with a good cable connected to a ready Host.

Can confirm that a GOOD cable can go BAD - works one minute then no longer working and a fresh cable does.
p#1 suggests it was connected at one point where 'zadig' showed the port.
Then zadig accurately shows the device ID when in Bootloader mode.

Also worth noting that the T_4.0 uses 480 Mbps USB that can fail to work where a lower speed device can reliably connect when the cable is not 'good enough'.
 
defragster said:
Can confirm that a GOOD cable can go BAD - works one minute then no longer working and a fresh cable does.
Click to expand...
I should have been more clear, i have also used other cables, and after this problem occured i have verified the ability for the cables to flash a teensy with another PC.
defragster said:
Also worth noting that the T_4.0 uses 480 Mbps USB that can fail to work where a lower speed device can reliably connect when the cable is not 'good enough'.
Click to expand...
The cable i am using is rated for 480 Mbps, i wouldn't expect there to be a problem, as again it works with other PCs.
PaulS said:
You may want to have a look at USBtreeview. This is the tool I use a lot for that purpose.
Click to expand...
I will take a look at this platform, thank you.
 
Teensy 4.x has a feature to wipe the flash and put a known-good LED blink program in. That program communicates as RawHID, not Serial. Arduino IDE should detect it.

To do the wipe, hold the pushbutton on Teensy for 15 seconds. You'll see a quick blink of the red LED after 13 seconds. You have a 4 second window starting at that moment, where releasing the button triggers the full erase and restore. The process is slow, over 1 minute on Teensy 4.1. Let it slowly run. When finished the red LED will turn off and the orange LED should blink again.

If the cable is working, your PC should detect a new HID device and Teensy should appear in the Tools > Ports menu.

However, I will also repeat what others have said. If you do a normal quick press (or long press more than 17 seconds) to go into bootloader mode, the red LED is supposed to stay on constantly. It gives a slow blink if absolutely no USB communication has been heard, not even the initial part of detecting a new device. That slow red LED blink exists because bad USB cables are such a common problem. Even if this cable was previously good, if you're seeing that slow blink on the red LED while in bootloader mode, it means Teensy has not heard any USB communication. A bad cable or hub is the only plausible explanation, since the USB host controller driver will always attempt to at least identify the device, because at that early stage it has no idea what driver will need to be loaded.
 
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