Memory Map:
* $c00000 r/w VDP DATA
* $c00002 r/w VDP DATA
* $c00004 r/w VDP STATUS(read)/CTRL(write)
* $c00006 r/w VDP STATUS(read)/CTRL(write)
* $c00100-$c0012f -/w VDP REGS(write only)
* $c00130-$c0015f -/w EXT VDP REGS(write only)
* $c00200-$c0024f r/w VSRAM
* $c00300-$c0030f r/w DIPSW
* $d00000-$d0ffff r/w 64KB VRAM
* $d10000-$d1ffff r/w 64KB EXT VRAM
??Detailed I/O Map spec omitted??