Serial disappearing after failed upload

N

nagra

Member
My Teensy 4.1 is no longer visible under Tools | Port

This happened as I uploaded my Sketch; I'm trying to remember what happened: I recall the LED came on and stayed on for some time like it was stuck there. I'm not sure if I unplugged the USB cable while it was on.

Now in OSX's System Information, the board shows up as:

SE Blank RT Family :

Product ID: 0x0135
Vendor ID: 0x1fc9 (NXP Semiconductors)
Version: 1.01
Speed: Up to 480 Mb/s
Manufacturer: NXP SemiConductors Inc
Location ID: 0x01100000 / 1
Current Available (mA): 500
Current Required (mA): 100
Extra Operating Current (mA): 0
Click to expand...

normally it shows up as:

USB Serial:

Product ID: 0x0483
Vendor ID: 0x16c0
Version: 2.80
Serial Number: 13172460
Speed: Up to 480 Mb/s
Manufacturer: Teensyduino
Location ID: 0x01100000 / 1
Current Available (mA): 500
Current Required (mA): 100
Extra Operating Current (mA): 0
Click to expand...
 
Does it show up in Teensy Loader if you press the pushbutton on Teensy. Every Teensy is made a button dedicate to entering Program mode to give you a way to recover from loading bad data.

This "SE Blank" can happen for because the flash memory is completely blank or doesn't contain enough data that looks like a program to even try to boot up. If you have a dodgy USB cable or if something goes wrong on your PC during uploading, you could end up with a the memory blank. Simply pressing the pushbutton should recover. Or you can try holding the pushbutton while plugging the cable in (though that was a bigger issue with older Teensy versions).

You can also get this error if Teensy has been physically damaged in a way that breaks the connection between the flash memory chip and main processor. From the CPU's point of view, if the flash chip isn't connected that looks basically the same as if it has no data at all.
 
Hey guys, thanks for the help.

When the problem happened I pressed the pushbutton of the Teensy but it didn't help.
Then I restarted Teensyduino and then rebooted my computer.

I didn't try pressing the pushbutton again... I just did and I saw the Teensy Loader activate and upload the Sketch. Once that was done, the board showed up in Teensyduino's Tools | Port.

(PS: I never tried holding the pushbutton for 15 seconds)
 
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