Zoran Djurisic

A4U microcontrollers are fantastic, and it would be great having a proper support for it. I have recently added here a board and variant files for 128A4U. All the A4Us...

Arduino folks have the cores for Cortex M0+, M3 and M4 (that's your STM32). It seems to me that all the board manufacturers are providing just the boards.txt entry, and...

I've generated pins_arduino.h and boards.txt entry for 128A4U. Not 100% tested yet, but so far, code doing digitalWrites and TWI on port C works as expected. [128A4U.zip](https://github.com/XMegaForArduino/arduino/files/889100/128A4U.zip)

Yes, I do have a board (I've seen your initial work, but it did not go far enough for me, I needed one to work now). I won't be using...

I should probably mention that the same code, just including Wire and RTClib, compiles fine for, say, Mega2560, or Nano or ProMini on 328 chip