68k memory map: Difference between revisions

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| 1MiB
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| Vector table, First fixed bank of the [[68k]] program ROM ([[P ROM]])
| [[68k_vector_table|Vector table]], First fixed bank of the [[68k]] program ROM ([[P ROM]])
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| $100000
| $100000

Revision as of 05:35, 5 September 2011

In Cartridge systems

Start End Size DEF Name Description
$000000 $0FFFFF 1MiB Vector table, First fixed bank of the 68k program ROM (P ROM)
$100000 $10F2FF 64KiB WORKRAM User RAM
$10F300 $10FFFF BIOS-reserved RAM
$200000 $2FFFFF 1MiB Second bank of the 68k program ROM (used for bankswitching and special chips)
$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 PALETTERAM Banked palette RAM
$800000 $BFFFFF 16 KiB max MEMORYCARD Memory card (8bit, even bytes are always $FF)
$C00000 $C1FFFF 128KiB BIOSROM System ROM (BIOS)
$D00000 $D0FFFF 64KiB Backup RAM (MVS only)

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 BIOS-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 PALETTERAM Banked palette RAM
$800000 $803FFF 8 KiB MEMORYCARD Virtual memory card (onboard battery-backed RAM)

(8bit, even bytes are always $FF)

$C00000 $C7FFFF 512KiB SYSTEMROM System ROM (BIOS)
$D00000 $DFFFFF ?
$E00000 $EFFFFF 1MiB UPLOAD Upload zone
$FF0000 $FF01FF ? CD specific i/o registers