Hi guys!!
I have been working the last months on a QMK version that uses a chinese/generic "bluepill" STM32F103C8T6. Thanks to Xydane (here in GH) who oriented me very well and showed me it's repository, I was able to keep working on it.
That's quite a powerful and cheap microcontroller for a keyboard (around 2$), I made a 70% layout and if someone is interested in creating more layouts, or adding functionanilities is welcome.
Maybe when the QMK pronton-c is finished has a similar firmware (probably better hahahaha) due to it is an ARM microcontroller too.
I made it to be easy to add more layouts and revisions. It has dual color backlight based on layers and capslock light.
I haven't used it on a real keyboard and, pluged into my laptop, somewhere in the top row (printscreen or start) make it hang the computer, but really I'm not very versed on C programming and microcontrollers, it has been everything about error/try.
I hope you enjoy it and improve it/use it.
https://github.com/qmk/qmk_firmware/tree/master/keyboards/handwired/bluepillOriginal post from Xydane:
https://geekhack.org/index.php?topic=93537.0;topicseen