This may be a totally dumb question based on the very very low level of coffein in my head this evening and therefore not being able to recognize the (may be) obvious ... nonetheless: Here comes the question:
With ATMega328-based boards there are quite a few GPIO-pins with some alternate functions like one UART, one SPI etc...most sketches out there are based on this design.
For my Nixie clock I need a lot more GPIOS (I dont want to multiplex the tubes, because this does radically shorten their lifetime (or gives you very dim glow)) so I bought a board based on the ATmega2560 (no USB though).
How are the pins named? Where can I find for example the file with the definition/configuration for a ATmega2560 based board which -- for example -- explain the compiler, that there is no GPIO D911? What configuration prohibits to read data from UART#7?
Is there any documentation, which explains, what is available (and name it syntactically correct)?
I mean...beside the 600++ pages of the ATmega2560 datasheet, which is not THAT Arduino compatible?
Thanks a lot for any help in advance ! Cheers mcc