Our PCB uses an ATmega2560 chip and uses most of the pins, including some that are not defined in the standard
pins_arduino.h module, since that module only provides for the pins that are brought out to headers on the Arduino Mega2560 PCB.
We have a modified
pins_arduino.h module that has all pins defined, but it doesn't get included in the Arduino IDE compile. It was cataloged in the same directory as the standard module (that we renamed
original). The path where the modified module is stored is
C:/Arduino/hardware/arduino/avr/variants/mega, where the original was also located.
In the sketch, we added
#include "pins_arduino.h" as well as
#include <pins_arduino.h>, but neither seemed to have included the modified module, so the extra pins are not accessible. Putting the module in the same library as the sketch didn't help either.