GPF (Troy Davis) has posted this following news about his port of the Gameboy Advance Emulator Visual Boy Advance to the Deamcast, heres what he posted in a DCEmu Forum Topic
Little update.
I have added controller support when playing a game, I still have to implement controller support in the menus.
Need some suggestions on what the keys should be mapped as.
Currently I have the joystick mapped to directions. Left trigger is left shoulder button, Right trigger is right shoulder button. GBA – ‘A” key is the X button on the dreamcast, and the GBA – ‘B” key is the A button on the dreamcast, Start button – Start and finally the select key is the Y button on the dreamcast.
Thanks,
Troy
More info Here