I've had my RPi for a little while now and I have successfully installed RetroPie and managed to configure most things to my liking so far. The only problem I'm having is I can't find any way to configure the Sega MasterSystem and Genesis control mappings. I'm currently using a PS3 controller but will switch to an Xbox 360 controller later if that matters. I've scoured the internet for any sort of information on the subject and I can't seem to find anything definitive. I might have passed by the answer unknowingly since I'm by no means an expert at Linux or terminal commands, I only started taking interest a few months back.
Any and all help would be appreciated, but I would please ask if you could explain layman term's.
Thanks in advance.