Hello,
First, thank you for your work on this project.

As your wiki says in the Pin description :

`12V 	B8 	B8 	Supply voltage, always on. 9 to 24V are fine. `

But at 24V, the ADC_button signal will rise to 4.29V from calc, but the pin PC4 on the STM32F103 is not 5V tolerant. Do I miss a protection on your schematic ? Max supply value seams to be under 18.45 V.

I will test FOCCCI on a 28V LVDC project, and I look for alternate references for non-28V tolerant components. I will submit them when I will test them.