Teensy 3.5 initially worked, but now not recognized by Win 10. COM port strangeness?

[JBeale]

Just received one T3.5 and one T3.6 from the Kickstarter. Both worked fine upon initial connection to my Win10 laptop. Using Arduino 1.6.12 and Teensyduino 1.31-beta1 I programmed both with the "Sdinfo" sketch from the SdFat-Beta project set to use SDIO and it printed out info on my SD cards as expected. I put them away, then I got another sd card I wanted to check out and found that the T3.5 device is not recognized as a USB device by Windows 10, it just doesn't exist. This was using the same cable as before. I also swapped cables but no go. I haven't soldered pins or attached anything to this board yet, just the microUSB cable and the uSD card. It is the same with or without the SD card.

I tried my T3.6 again and that worked fine, showing up on COM5. Then I disconnected the T3.6 and noticed that the Arduino GUI under "Toolsort" still showed the COM5 device as available. I'm pretty sure in the past, when I disconnected a Teensy it would disappear from the listing of available COM ports. What changed? When I try to open the serial window after disconnect I see "Error opening serial port 'COM5'. (Port not found)" however it is still showing in Toolsort. If I close the Arduino GUI and then reopen, then now the "Port" item is all greyed out and no COM port is available, as I would expect with no physical devices connected.

Seems like an Arduino bug, or maybe Windows?

UPDATE: tried the T3.5 board again. Still not recognized as a COM port upon initial connection, but this time pressing the program button triggered the Teensy loader and it was programmed. Arduino says it is now COM6. Closed the serial window and re-opened, now get an error "no serial port name defined". Closed and reprogrammed, now it works fine still on COM6. Hmmm.

 

[defragster]

T_3.5's report serial number fine at any speed - so the com port should stick - if acting right - unlike a T_3.6 over 120 MHz.

Are you at default 120 MHz?

TYQT is a better SerMon (Sees all Teensy by device not COM#) - but since it isn't tied to drop Serial (unless integrated) - it hides the device from TeensyLoader unless you click Serial Off. TYQT works better when ' Tools / Integrate ' is done - that replaces TeensyLoader - then close Teensy Loader and see if it shows anything else or works right.

IDE remember COM # even after they are gone - very confusing - if you connect 5 or it moves 5 times they all show it seems and you have to guess the active one, IDE SerMon is a waste of life energy (on Windows at least)see above.

I have an odd acting T_3.6 I'm going to post about . . .

 

[cow_n_berg]

UPDATE: tried the T3.5 board again. Still not recognized as a COM port upon initial connection, but this time pressing the program button triggered the Teensy loader and it was programmed. Arduino says it is now COM6. Closed the serial window and re-opened, now get an error "no serial port name defined". Closed and reprogrammed, now it works fine still on COM6. Hmmm.

This just worked for me. The Teensy did not make it all the way to a USB Serial Device. Thanks!