HELP - I have two Teensy's with same COM Port Number

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mendez

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I have a weird issue with my Teensy's 3.6. I have two different boards and when I plug the first board to the PC; it will show COM Port 20; if I unplug the first board to plug the second board; then the second board will show as COM Port 20 too (same as the first board). Also, the serial numbers are the same too!

I haven't plug both boards at the same time. Any help will be appreciated.
 
Have either or both been programmed with a sketch from new? A sketch with USB Serial active? Even Blink?

If the IDE and TeensyLoader are used to install even a blink sketch with USB Serial they should properly report and be recognized.
 
They are recognized. Both boards have been programmed with a sketch without any issues. The only issue I have is that both have the same com port & serial numbers. In theory, they should be unique (each one with different com ports)
 
I bought them from you directly. I bought a couple of the MKL02 from your store to create my own teensy 3.6
 
They are recognized. Both boards have been programmed with a sketch without any issues. The only issue I have is that both have the same com port & serial numbers. In theory, they should be unique (each one with different com ports)

Interesting - that is quite right - they should be unique once they are ID'D. PJRC has process in place to assign unique Serial #'s.

Not seen this before on Windows - don't know OS in use? IDE and Teensyduino version ?

Some code could print the serial # from within a sketch (forum has links or steal it from the PJRC core). Looked the other day and TeensyLoader Verbose doesn't seem to expose a device Serial#.

With TyCommander (search Forum) installed it will present a UI with info about the COM port and Serial#

Perhaps another computer or rebooting this one.

One other thing might be to try the eat-3.6's 15 second Restore in turn plug each in start a timer with running second count: Hold Program button as 15 seconds pass and release. If anything unsettled the Teensy that will put the chip back to proper factory state - except there will not be any active sketch - and no USB presentation to PC - until reprogrammed.
 
I bought them from you directly. I bought a couple of the MKL02 from your store to create my own teensy 3.6

This cross-posted while sleeping on the last post. Any self made will not have a unique Serial # until burned into the MCU area. Mixing and matching may confuse the PC.
 
Yup, custom made boards will have a blank serial number (all 1s) in the MK66's "program once" memory. Easiest thing to do is edit usb_desc.c and put your own number into the code.

The serial number is *NOT* stored in the MKL02 chip.

Windows uses the serial number the distinguish between physical hardware and associate the COM port number.
 
Yup, custom made boards will have a blank serial number (all 1s) in the MK66's "program once" memory. Easiest thing to do is edit usb_desc.c and put your own number into the code.

The serial number is *NOT* stored in the MKL02 chip.

Windows uses the serial number the distinguish between physical hardware and associate the COM port number.

Oh OK, makes sense! Thanks. So, is there a way to assign a unique serial number automatically for mass produced boards? Or do I need to edit usb_desc.c each time I load a firmware to the board?
I will look into editing usb_desc.c

Thanks again!
 
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