Continuing porting the Mosquino
project (ATmega644pa) to the 1.0 core, I finally decided to chase down the INT2 pin issue
that's been bothering me since 0022. Lo and behold... only INT0 and INT1 are handled, or even allowed, in WInterrupts.c.
In fact, it looks like somebody went to some length to remove all support for INT2 for the non-ginormous chips (e.g. #define EXTERNAL_NUM_INTERRUPTS 2 in wiring_private.h). Based on the trouble gone to, I assume this was done for some kind of important reason. Does anyone have a clue what that reason is/was?
Does use of the INT2 pin break horribly on some old Arduino board / AVR flavor (chip erratum) / avr-gcc version?
Was a lead developer hurting for a couple bytes Flash/RAM and decided 2 interrupts were enough?
Could it really have just been an oversight after all?
I have re-added it and it seems to work fine on my board, but I'm curious if I'm undoing someone's significant research and some bizarre issue will come to bite later.