This is a configurable Atmel processor and support eight configurations:
7) ENHANCED_4M (Not supported yet)
I provide the links directly to GIT repository projects for easy update ( This is divided in multiple projects SOFTWARE/RTL/SCH... ).
The processor IP and several IO IP's and can be downloaded from here: https://github.com/dev-board-tech/hdl-core-mega-xmega
A complete implementation for a Atmega32U4 that completely emulate and add some more features to an arduboy :
HEX/BIN to mem file converter utility: https://github.com/dev-board-tech/intel-hex-to-rtl-mem
All details about this core on GIT