A LED cube probably takes more or less all your processing power, so if you’re planning to have this as part of your design it would be safe to say that this should be done by a separate processor.
Before jumping into something like this --This project requires some programming concepts that are a little advanced, I would suggest just one LED. I know this seems a bit simplistic, but if you are new to microcontrollers, you will really need to start at the beginning. --A blinking LED is the “Hello World” of robots.