SparkFun Forums

[mcannist]

Hi all.

I have a SparkFun Pro Micro 3.3V / 8 MHz bricked (all 3 LED are on when powered via USB cable).
I tried in several ways to upload the bootloader again to unbrick it but only got errors.

Here is a short description of the sequence of events/steps:

- Months ago I successfully worked on the Sparkfun Pro Micro and then on a Teensy 3.1 using the same dev environment with Arduino IDE 1.0.5.

- Recently I had to reinstall my laptop so I got the new IDE 1.6.5-r5 installed and successfully tested it with the Teensy.

- Then I wanted to test it with the Pro Micro but forgot to switch board on the menu and wiped the bootloader (!)

- the board is now behaving like described here: https://learn.sparkfun.com/tutorials/pr ... #ts-revive (USB device not recognized, all LED on)

- it is listed on device manager as in attachment dev_man_unknown_device.png

- when i realized it was bricked I also reminded that i did not install the Sparkfun add-on files. So I got from github the url for the IDE board manager and installed the SparkFun files using the new tool/procedure.

- I selected the proper board and version on the menu ( SparkFun Pro Micro 3.3V / 8 MHz )
- I selected the AVRISP mkII programmer ( see attachment ide_setup_to_burn_bootloader.png)

- I tried the revive procedure wiring the reset pin to use the "2x press procedure" and enter the 8 sec bootloader mode. The board actually goes to bootloader mode, but when I try to burn bootloader from the IDE as described I get an error: "avrdude: usbdev_open(): did not find any USB device "usb"
Error while burning bootloader."

- during the 8 sec bootloader mode the board is listed on device manager as in attachment dev_man_pro_micro.png

- this the error messag i get when trying to burn the bootloader:
"avrdude: usbdev_open(): did not find any USB device "usb"Error while burning bootloader"
(see attachment ide_error_message1.txt )

- I have an AVR Pocket programmer so I also tried wiring it and then use the other procedure described here: https://learn.sparkfun.com/tutorials/in ... bootloader

- being the vcc output at 5V i connected it to the RAW voltage input of the 3.3v Pro Micro

- i double checked all the wirings as suggested (see attachments wiring1.jpg and wiring2.jpg)

- in this case I selected the USBtinyISP programmer on the IDE menu ( see attachment ide_setup_for_pocket_programmer.png)

- I've seen some short traffic going on the AVR Pocket programmer and i've also seen the Pro Micro yellow and green led going off for a brief time. But then they switch on again and i get this other error message:
"avrdude: programmer operation not supported
avrdude: Using SCK period of 10 usec
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override this check."
(see attachment ide_error_message2.txt )

Does anyone in the forum have suggestions about what else I could check or try ?

thank you,
mario

[Ross Robotics]

Try to use some of the suggestions here, https://forum.sparkfun.com/viewtopic.php?f=32&t=31955

[mcannist]

Hi codlink.
Thank you for your suggestion.
I've already tried the steps in that thread but without any luck.
I also tried some slight changes using avrdude from the command line.

One thing I noticed is that, when using avrdude with the -F option, I get different signature values on every trial. ...and it is different from the one expected for the atmega32u4. Is the signature stored in the flash so that i could have written over that? If it is not in the flash then i could think of some communication issue that alters the read values when they go from the board to the programmer. Also, the programmer is new (never used before, bought it just in case). I'm still searching for info to understand if it is normal to have those led on when i power on the programmer through the usb cable (see picture in previous post attachment).

I also thought at issues with the logic levels voltage difference between the programmer (5V ?) and my Pro Micro at 3.3v. But then I read that "the atmega32u4 is 5v tolerant" in some post so they should work well together.

Solved !
On Saturday I decided to repeat the suggested steps with the double-tap reset procedure.
Still I was not able to upload within the 8 seconds.

Then I noticed an important detail that I actually didn't notice when reading the instructions: "...upload an empty sketch..."

I was uploading my program with the implicit build being performed by the IDE and, even without the verbose flag, the whole thing was just taking too much... The only way to shrink the time taken by the build/upload process is to use an empty sketch !!
Next time I will read three times before trying.... :whistle:

[prosise]

Empty.. Woohoo, thanks.. I was chasing my tail until I used an empty sketch.. Pcb is now a pro micro again.. Much appreciated. ..

Prosise

[mcannist]

Hello Prosise.
Happy to read this has been useful for you as well
Bye,
Mario