Memory Map
Official Memory Map
The "official" memory map published by Mattel is included below.
| Memory Range | Accessibility | Device |
|---|---|---|
| $0000-$003F | RW, VBlank Period 1 | STIC Registers |
| $0100-$01EF | RW | Scratchpad RAM |
| $01F0-$01FF | RW | PSG Registers |
| $0200-$035F | RW | System RAM |
| $1000-$1FFF | R | Executive ROM |
| $3000-$37FF | R, VBlank Period 2 | Graphics ROM |
| $3800-$39FF | RW, VBlank Period 2 | Graphics RAM |
Additional Memory Aliases
Note that the official memory map shown above is actually incomplete, due to the fact that the STIC and the Graphics RAM chip incompletely decoded addresses that were placed on the address bus.
| Memory Range | Accessibility | Device |
|---|---|---|
| $3A00-$3BFF | RW, VBlank Period 2 | Graphics RAM |
| $3C00-$3DFF | RW, VBlank Period 2 | Graphics RAM |
| $3E00-$3FFF | RW, VBlank Period 2 | Graphics RAM |
| $4000-$403F | W, VBlank Period 1 | STIC Registers |
| $7800-$79FF | W, VBlank Period 2 | Graphics RAM |
| $7A00-$7BFF | W, VBlank Period 2 | Graphics RAM |
| $7C00-$7DFF | W, VBlank Period 2 | Graphics RAM |
| $7E00-$7FFF | W, VBlank Period 2 | Graphics RAM |
| $8000-$803F | W, VBlank Period 1 | STIC Registers |
| $B800-$B9FF | W, VBlank Period 2 | Graphics RAM |
| $BA00-$BBFF | W, VBlank Period 2 | Graphics RAM |
| $BC00-$BDFF | W, VBlank Period 2 | Graphics RAM |
| $BE00-$BFFF | W, VBlank Period 2 | Graphics RAM |
| $C000-$C03F | W, VBlank Period 1 | STIC Registers |
| $F800-$F9FF | W, VBlank Period 2 | Graphics RAM |
| $FA00-$FBFF | W, VBlank Period 2 | Graphics RAM |
| $FC00-$FDFF | W, VBlank Period 2 | Graphics RAM |
| $FE00-$FFFF | W, VBlank Period 2 | Graphics RAM |
