I’m running into trouble with this part of the hookup guide:
https://learn.sparkfun.com/tutorials/qw … -and-linux
It doesn’t say much about linux. After a couple seconds of plugging in the device, it disappears from the IDE!
I tried ‘sudo apt-get purge modemmanager’, and that didn’t work.
I tried adding this: etc/udev/rules.d/77-mm-usb-device-blacklist-local.rules
ACTION!=“add|change”, GOTO=“mm_usb_device_blacklist_local_end”
SUBSYSTEM!=“usb”, GOTO=“mm_usb_device_blacklist_local_end”
ENV{DEVTYPE}!=“usb_device”, GOTO=“mm_usb_device_blacklist_local_end”
ATTRS{idVendor}==“1b4f” ATTRS{idProduct}==“9205”, ENV{ID_MM_DEVICE_IGNORE}=“1”
ATTRS{idVendor}==“1b4f” ATTRS{idProduct}==“9204”, ENV{ID_MM_DEVICE_IGNORE}=“1”
ATTRS{idVendor}==“1b4f” ATTRS{idProduct}==“9203”, ENV{ID_MM_DEVICE_IGNORE}=“1”
ATTRS{idVendor}==“1b4f”, ENV{ID_MM_DEVICE_IGNORE}=“1”
LABEL=“mm_usb_device_blacklist_local_end”
and that didn’t work.
Any ideas?
I’m using Linux Mint 19.3 Tricia
I also tried this on a mac, and the same thing happened. The board appeared, then disappeared.
Have you tried on a PC?
If you double click the reset button, does that make a COM port appear?
Did the board originally work and then stop working after uploading the first sketch?
Thanks for the response Chris.
Here’s what I’ve found.
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I don’t have easy access to a Windows PC at this time.
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When I double click the reset button, the /dev/ttyACM0 port come back for a few seconds, then disappears.
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Funny you should say that. I think it did download the first time because I saw tx/rx LEDs blinking the first time I tried to download a sketch. The IDE said the sketch downloaded, but the only output the sketch has is serial.println - no blinkin lights so I was unable to confirm. When I tried to download a second time, the /dev/ttyACM0 port was gone.
Thanks for your help!
OK that means you’ve uploaded to the board with the wrong board definition. The IDE defaults to the 3.3 volt board and you likely have a 5 volt board. When you upload a sketch with the wrong board definition, you ‘brick’ it, but it’s recoverable.
First thing you need to do is make sure you have the right board and voltage selected in the IDE.
The you need to follow the directions in the “How to Revive a “Bricked” Pro Micro” section of the [hookup guide.
It’s tricky to get the timing right so it might take several tries, but eventually this will recover your board.](Qwiic Pro Micro USB-C (ATmega32U4) Hookup Guide - SparkFun Learn)
Is it necessary to start another thread as I have the same issue?
My board is not bricked, that is, I can upload other sketch (once I get the reset/upload timing right)… The board is 3.3V with correct board selected i.e. 3.3 8Mhz…
Before the initially program was uploaded the board worked perfectly being recognised all the time, but once programmed it appears for a few seconds (assume boot sequence), then disappears… I should note the all test program works perfectly but without being able to send keyboard data it’s kinda useless…
Also tested on my Windows system and the same results except to note Windows appears to recognise the board after programming but it indicated it’s an unknown/unrecognised device or something to that effect…
Any ideas?
Mike
Michael,
They symptoms you’re describing are exactly consistent with a bricked board. Are you absolutely certain you have a 3.3 volt board and not the 5 volt? The symptoms for programming a 3.3 volt board as a 5 volt on OR a 5 volt board as a 3.3 volt one are identical.
I will double check… done, your absolutely right, I have 5 volts at VCC but it’s strange the pads are not shorted…
More when I fins out why… many thanks, I can stop pulling my hair out now 
Mike
Just to clarify, the LDO used on my board was marked as 4BMD which is 5 volt not a 3.3 volt LDO, so it makes no difference if the pads are shorted, it will always be a 5 Volts board. I also note the board was sold as a 3.3 volt device…
If your Pro Micro is not functioning as intended and it’s a 3.3 volt version, check your LDO…
