The Arduino LLC set out to accomplish some very specific goals with the Arduino, and one of these was to make programming Arduinos as simple as possible for beginners. Most hardware interactions involve digitalRead() and digitalWrite() or some variation on those two functions. These are useful functions, but they’re an abstraction—there’s that word again—from how the ATmega really communicates with the outside world.
So far as the ATmega1284P (or any other ATmega used in Arduinos that I’m aware of) knows, there is no such thing as pin 1 (in the Cestino’s case.) It knows that pin only as ...
