Sega Saturn Memory Map

Edit on Github | Updated: 17th October 2020

Main memory Map

The table below highlights the main areas that can be accessed in Sega Saturn games.

Start End Name Description
0x00 0x000FFFFF Boot ROM Repets every 512 kb
0x00100000 0x0017FFFF SMPC registers  
0x00180000 0x001FFFFF Backup RAM  
0x00200000 0x002FFFFF Work RAM Low  
0x00300000 0x003FFFFF Random data Random on every read (mostly 0x00)
0x00400000 0x007FFFFF Zero Always returns 0x0000
0x00800000 0x00FFFFFF Unknown Always returns 0x00000001000200030004000500060007
0x01000000 0x017FFFFF Master Init (MINIT) Data written goes to Master SH-2 Free Running Timer. Section is Write Only.
0x01800000 0x01FFFFFF Slave Init (SINIT) Data written goes to Slave SH-2 Free Running Timer. Section is Write Only.
0x02000000 0x03FFFFFF CS0 Cartridge 0
0x04000000 0x04FFFFFF CS1 Cartridge 1
0x05000000 0x057FFFFF Dummy  
0x05800000 0x058FFFFF CD-ROM registers (CS2) Repeats every 64 Bytes
0x05900000 0x059FFFFF Unknown It will lockup the saturn when read
0x05A00000 0x05AFFFFF 68000 Audio Work RAM Stores audio data that will be played
0x05B00000 0x05BFFFFF SCSP registers  
0x05C00000 0x05C7FFFF VDP1 VRAM Video RAM for the 3D VDP1
0x05C80000 0x05CFFFFF VDP1 Framebuffer Current Image Buffer for the VDP1 to render to
0x05D00000 0x05D7FFFF VDP1 Registers VDP1 variables that change the functionality of how the VDP1 operates
0x05D80000 0x05DFFFFF Lockup when read  
0x05E00000 0x05EFFFFF VDP2 VRAM Video Display Processor 2 (Background) Video RAM - Repeats every 512 kb
0x05F00000 0x05F7FFFF VDP2 CRAM VDP2 Color RAM - Basically the background Palette - Repeats every 4kb
0x05F80000 0x05FBFFFF VDP2 registers VDP2 variables that change the functionality of how the VDP2 operates - Repeats every 512 bytes
0x05FC0000 0x05FDFFFF Unknown Always returns 0x000E0000
0x05FE0000 0x05FEFFFF SCU registers Repeats every 256 bytes
0x05FF0000 0x05FFFFFF Unknown registers Repeats every 256 bytes
0x06000000 0x07FFFFFF Work RAM High  

References