This is the worldwide first real Atmega328PB support package for Arduino! No hooks. Look at my uino-hardware Repo for Schematic of my Boards. This package lets you compile your code for the Atmel Atmega328PB Microcontroller. There is no additionally compiler needed. You can compile out of the box.
Arduino IDE 1.6.9 or higher which contains avr-gcc in Version 4.9.2
Copy this link into your Arduino IDE.
https://raw.githubusercontent.com/amoehl/uino-atmega328pb/master/package_atmega328pb_index.json
Run "Bord Manager" -> Contributed -> Atmega328PB -> Install
This Package currently supports only my own developed boards. More Information: https://github.com/amoehl/uino-hardware