This is the source code for a Gamecube/N64 controller to USB adapter firmware meant to run on raphnet.net Multiuse PCB-X.
The project homepage is located at: http://www.raphnet.net/electronique/multiuse_pcbX/index.php
The project is released under the General Public License version 3.
You will need a working avr-gcc toolchain with avr-libc and standard utilities such as make. Just type 'make' and it should build just fine. Under Linux at least.
The makefile has a convenient 'flash' target which sends a command to the firmware to enter the bootloader and then executes dfu-programmer (it must of course be installed) with the correct arguments.