Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
The gui isn't letting me map keys to buttons - I can map controller buttons to key strokes but I think the 5200 emulator is looking for input from a keypad and not a keyboard - I'm really new to this, so I'm probably missing something simple.
@gpmcty You probably figured this out a long time ago but the config file is in the /opt/retropie/configs/atari800/ folder.