 Actually, only few of them are used. Many of them are just mirrors. The ones used are:<br><br>&#036;c00000 - the data port (where you put data after programming the control port)<br>&#036;c00004 - the control port<br>&#036;c00008 - hv counter (when you read that, it returns the current H Line and VLine being rendered)<br>&#036;c00011 - PSG - this port is used to program PSG from the 68k. <br><br> 