Experience with the Micro ATmega32U4-MU?

Hi Everyone, first post on the forum so please forgive me if I’m asking in the wrong forum or breaking any rules I missed. I’m a complete noob so I might be asking a really silly question, but here goes :slight_smile:

I’m currently designing my first custom board and will be using at least 77 keys. In order to keep the matrix simple and clean I would like to use an MCU that has enough pins to wire the rows and cols up without too much wire juggling.

The arrangement is 12 cols by 7 rows so just beyond what the trusty Pro Micro ATmega32U4 can handle with its 18 pins (without the LED mod to open up 2 additional). After some searching I found the Micro ATmega32U4-MU from RobotDyn which looks like it should be compatible, not too big and have enough pins for the project exposed.

Does anyone have any experience with this controller? Would it indeed be code compatible with qmk firmware?

Thank you!

Yup, the 32u4 is mainstay within keyboard PCB design, and all breakout boards are pretty much identical as far as their functional elements are concerned. As long as the actual controller is supported by QMK, the board should work.

Shameless self promotion if you’re interested in building your PCB from scratch:


Thank you! Your video series was actually what finally pushed me to consider doing my own design from scratch. :slight_smile: Thank you so much for putting those together they are truly helpful.

I’ve built a lot of kits but the whole world of CAD and PCB design is new to me so lots to learn.

However, I have my own custom design ready in Fusion 360 and have 3d printed it and tested it with actual switches (though no wiring). I also have the matrix sketched and ready to go but was planning on hand-soldering a prototype just to make sure I’m on the right path.