Yes, its Genesis 6 button Pads that used microcontroller. Sega Master system had basically an atari standard port, Genesis 3 button pads added select signal fo

Yes, its Genesis 6 button Pads that used microcontroller. Sega Master system had basically an atari standard port, Genesis 3 button pads added select signal for swapping two pages (alternating between a/b c/start), finally 6 button controller added third page, but to trigger it you needed to pulse select line 3 times, and this was deemed to complex for discrete logic, hence microcontroller in 6 button pads.