Hey guys. What I have made is a compact, 1 wide PFF. "Whats a pulse flip flop?" you may ask. Well, it is basically a RSNOR hooked into a delay, then into a mux. IE: You push the button once, the pulse doesn't go through. You push it again, and it does. The output is from the top of the cell, not exactly practical, but it works :smile.gif: Useful for Space Invaders, or other games where it requires you to shoot something before another. Feedback would be excellent.
Well, say you want 2 lines of enemys, you send a pulse, it sets the RSNOR to open the mux. But the pulse doesn't go through to the next yet. But from whenever you push the button after that, it goes straight through.
I just finished building my Space invaders lite v.2 with 8 enemys on 2 rows.