QWIIC Pro Micro disappeared from Windows Device Manager

Qwiic System
1

First, QWIIC daisy chain worked well (1a)-(2)-(3)-(4)

(1a) DEV-15795 Pro Micro USB-C

(2) LCD-14532 OLED module

(3) DEV-15164 Openlog

(4) SEN-15219 Pulse Oximeter

Next,

(5) BOB-16281 RTC Module

was added to form daisy chain (1a)-(5)-(2)-(3)-(4).

Although an Arduino sketch was successfully loaded to (1a), it was the first and the last time (1a) accepted sketch.

COM4 port of (1a) has disappeared from my Windows Device Manager, and was never retrieved even with RESET sequences described in the Pro Micro USB-C Hookup Guide.

This phenomena was found to be repeatable, because another Pro Micro USB-C (1b) has died in the same way.

COM4 port of (1b) has disappeared from my Windows Device Manager two minutes after (1b) accepted sketch for the first time.

Could you find the root cause of this phenomena and effective way to recover Pro Micro USB-C?

2

The Arduino Pro Micro has a AVR ATmega32u4 which, unlike most other Arduinos, has its own built-in USB interface. This can, on occasion, cause some problems where the Micro gets into problems. I’ve had many cases with connection problems after loading bad sketches. I’ve found that this can get resolved with good timing of a compile/upload (best use an innocuous sketch like “blink” for this) and hitting the reset button on the board, but sometimes it will take several attempts.

I have several Pro-Micros and use them as main development board. I had one that I thought I’d bricked (played around with sleep modes and fuses and wasn’t careful enough) and I finally got that working by putting a new bootloader onto it. At the time I used an Arduino UNO to program the bootloader, but now have a USB-ASP that can do the same. Do you have either of these? In that case, there are several sites on the Internet with good descriptions (including pictures) of how to do this.

3

Thanks for the posts.

SV-Zanshin is spot on about the 32U4 being a little finicky when it comes to COM port issues and getting bricked easily.

We do have a troubleshooting guide on how to revive a bricked 32U4 device that you can check out here: https://learn.sparkfun.com/tutorials/qw … ng-and-faq

The “reset bootloader” section is very specific and like SV-Zanshin states it may take a few attempts to get the reset button press timing correct.

Try it out, let us know if you still run into issues. If you plan on using devices with this processor you may want to familiarize yourself on how to un-brick them.