All depends on which microcontroller it is using. The Propeller microcontroller has multiple cores and specialized registers for video, so it can just dedicate

All depends on which microcontroller it is using. The Propeller microcontroller has multiple cores and specialized registers for video, so it can just dedicate independent core to video and bus control. An Arduino is certainly fast enough to bit bang video, and it could probably interleave bus control between servicing pixels, but the code and timing for that would get complex.