68k memory map
In Cartridge systems
To do: More details in the $300000 range, especially mirroring. See MAME's source and address decoding signals.
| Start | End | Size | DEF Name | Wait cycles | Description |
| $000000 | $0FFFFF | 1MiB | 0 or 1 (4/5 clks) depending on ROMWAIT. | Vector table, first fixed bank of the 68k program ROM (P ROM) | |
| $100000 | $10F2FF | 64KiB | WORKRAM | 0 (4 clks) | User RAM |
| $10F300 | $10FFFF | System ROM-reserved RAM | |||
| $110000 | $1FFFFF | 0 (4 clks) | Work RAM mirror | ||
| $200000 | $2FFFFF | 1MiB | 0 to 3 (4/7 clks) depending on PWAIT. | Second bank of the 68k program ROM (also used for bankswitching and access to special chips) | |
| $300000 | $3FFFFF | 0 (4 clks) | I/O. See Memory mapped registers and GPU. | ||
| $400000 | $401FFF | 8KiB | PALETTES | 0 (4 clks) | Banked palette RAM |
| $402000 | $7FFFFF | 0 (4 clks) | Palette RAM mirror | ||
| $800000 | $BFFFFF | 8 MiB max | MEMCARD | 2 (6 clks) | Memory card |
| $C00000 | $C1FFFF | 128KiB | SYSTEMROM | 0 (4 clks) | System ROM |
| $C20000 | $CFFFFF | 0 (4 clks) | System ROM mirror | ||
| $D00000 | $D0FFFF | 64KiB | 0 (4 clks) | Backup RAM (MVS only) | |
| $D10000 | $DFFFFF | 0 (4 clks) | Backup RAM mirror |
In CD systems
| Start | End | Size | DEF Name | Description |
| $000000 | $0FFFFF | 2MiB | Vector table, 68k program (PRG files), 68k RAM | |
| $100000 | $10F2FF | 64KiB Shared with the 68k code DRAM. |
WORKRAM | User RAM |
| $10F300 | $10FFFF | System ROM-reserved RAM | ||
| $110000 | $1FFFFF | 68k program ? | ||
| $300000 | $39FFFF | Input ports (See Memory mapped registers) | ||
| $3A0000 | $3BFFFF | Ouput ports (See Memory mapped registers) | ||
| $3C0000 | $3FFFFF | GPU ports (See Memory mapped registers) | ||
| $400000 | $401FFF | 8KiB | PALETTES | Banked palette RAM |
| $800000 | $803FFF | 8 KiB | MEMCARD | Virtual memory card (onboard battery-backed RAM) (8bit, even bytes are always $FF) |
| $C00000 | $C7FFFF | 512KiB | BIOSROM | System ROM |
| $D00000 | $DFFFFF | ? | ||
| $E00000 | $EFFFFF | 1MiB | UPLOAD | Upload zone |
| $FF0000 | $FF01FF ? | CD and DMA specific I/O registers |
For Neo Print boards
Infos from [MAME's source].
| Start | End | Size | DEF Name | Description |
| $000000 | $07FFFF | 512KiB | 68k program (P ROM). | |
| $100000 | $17FFFF | Banked 68k program or I/O (writes done here). | ||
| $200000 | $20FFFF | 64KiB | 68k RAM | |
| $300000 | $30FFFF | 64KiB | Backup RAM | |
| $400000 | $43FFFF | VRAM ? | ||
| $500000 | $51FFFF | 128KiB | Palette RAM | |
| $600000 | $600001 | Z80 I/O | ||
| $600002 | $600003 | RTC I/O | ||
| $600004 | $60000D | I/O registers | ||
| $700000 | $70001B | GPU registers | ||
| 70001E | 70001F | Watchdog |