View source for Sega Mega Drive/Memory map

{|class="prettytable"
! Start address || End address || Description || 32X SH-2 address
|-
| $000000
| $3FFFFF
| Cartridge ROM/RAM
| $2000000-$23FFFFF
|-
| $400000
| $7FFFFF
| Reserved (used by the Mega-CD and 32X)
|-
| $800000
| $9FFFFF
| Reserved (used by the 32X)
|-style="background:lightyellow"
| $840000
| $85FFFF
| 32X frame buffer
| $4000000-$401FFFF
|-style="background:lightyellow"
| $860000
| $87FFFF
| 32X frame buffer overwrite mode
| $4020000-$403FFFF
|-style="background:lightyellow"
| $880000
| $8FFFFF
| 32X cartridge ROM (first 512kB bank only)
|-style="background:lightyellow"
| $900000
| $9FFFFF
| 32X cartridge bankswitched ROM (any 512kB bank, controlled by 32X registers)
|-
| $A00000
| $A0FFFF
| Z80 memory space
|-
| $A10000
| $A10001
| Version register
|-
| $A10002
| $A10003
| Controller 1 data
|-
| $A10004
| $A10005
| Controller 2 data
|-
| $A10006
| $A10007
| Expansion port data
|-
| $A10008
| $A10009
| Controller 1 control
|-
| $A1000A
| $A1000B
| Controller 2 control
|-
| $A1000C
| $A1000D
| Expansion port control
|-
| $A1000E
| $A1000F
| Controller 1 serial transmit
|-
| $A10010
| $A10011
| Controller 1 serial receive
|-
| $A10012
| $A10013
| Controller 1 serial control
|-
| $A10014
| $A10015
| Controller 2 serial transmit
|-
| $A10016
| $A10017
| Controller 2 serial receive
|-
| $A10018
| $A10019
| Controller 2 serial control
|-
| $A1001A
| $A1001B
| Expansion port serial transmit
|-
| $A1001C
| $A1001D
| Expansion port serial receive
|-
| $A1001E
| $A1001F
| Expansion port serial control
|-
| $A10020
| $A10FFF
| Reserved
|-
|colspan=2| $A11000
| Memory mode register
|-
| $A11002
| $A110FF
| Reserved
|-
| $A11100
| $A11101
| Z80 bus request
|-
| $A11102
| $A111FF
| Reserved
|-
| $A11200
| $A11201
| Z80 reset
|-
| $A11202
| $A12FFF
| Reserved
|-
| $A13000
| $A130FF
| TIME registers; used to send signals to the cartridge
|-
| $A130EC
| $A130EF
| "MARS" when 32X is attached
|-
|colspan=2| $A130F1
| [[Sega Mega Drive/SRAM|SRAM access register]]
|-
|colspan=2| $A130F3
| [[Sega Mega Drive/Bank switching|Bank register]] for address $80000-$FFFFF
|-
|colspan=2| $A130F5
| Bank register for address $100000-$17FFFF
|-
|colspan=2| $A130F7
| Bank register for address $180000-$1FFFFF
|-
|colspan=2| $A130F9
| Bank register for address $200000-$27FFFF
|-
|colspan=2| $A130FB
| Bank register for address $280000-$2FFFFF
|-
|colspan=2| $A130FD
| Bank register for address $300000-$37FFFF
|-
|colspan=2| $A130FF
| Bank register for address $380000-$3FFFFF
|-
| $A14000
| $A14003
| [[TMSS]] "SEGA"
|-
|colspan="2"| $A14101
| [[TMSS]]/cartridge register
|-
| $A14102
| $BFFFFF
| Reserved
|-
| $C00000
| $C00001
| VDP [[Sega Mega Drive/VDP general usage#Data port|data port]]
|-
| $C00002
| $C00003
| VDP data port (mirror)
|-
| $C00004
| $C00005
| VDP [[Sega Mega Drive/VDP general usage#Control port|control port]]
|-
| $C00006
| $C00007
| VDP control port (mirror)
|-
| $C00008
| $C00009
| VDP [[Sega Mega Drive/VDP general usage#H/V counter|H/V counter]]
|-
| $C0000A
| $C0000F
| VDP H/V counter (mirror)
|-
|colspan="2"| $C00011
| PSG output
|-
| $C00013
| $C00017
| PSG output (mirror)
|-
| $C0001C
| $C0001D
| Debug register
|-
| $C0001E
| $C0001F
| Debug register (mirror)
|-
| $C00020
| $FEFFFF
| Reserved
|-
| $FF0000
| $FFFFFF
| 68000 RAM
|}

[[Category:Mega Drive technical information|Memory map]]