-- | On the arduino, digital pin numbers are in 1-to-1 match with
-- the board pins. However, ANALOG pins come at an offset, determined by
-- the capabilities query. Users of the library refer to these pins
-- simply by their natural numbers, which makes for portable programs
-- between boards that have different number of digital pins. We adjust
-- for this shift here.
getInternalPin :: Pin -> Arduino IPin
getInternalPin (MixedPin p)   = return $ InternalPin p
getInternalPin :: Pin -> Arduino IPin
getInternalPin (MixedPin p)   = return $ InternalPin p
getInternalPin (MixedPin p)   = return $ InternalPin p