Atari 7800 Memory Map by Daniel Boris (11/9/98) 0000 - 001F TIA 0020 - 003F MARIA 0040 - 00FF RAM block 0 0100 - 011F TIA (mirror of 0000-001F) 0120 - 013f MARIA (mirror of 0020-003F) 0140 - 01FF RAM block 1 0200 - 021F TIA (mirror of 0000-001F) 0220 - 023F MARIA (mirror of 0020-003F) 0280 - 02FF RIOT I/O ports 0300 - 031F TIA (mirror of 0000-001F) 0320 - 033F MARIA (mirror of 0020-003F) 0480 - 04FF RIOT RAM 0580 - 05FF RIOT RAM (mirror of 0480-04FF) 1800 - 27FF RAM 2040 - 20FF RAM block 0 (mirror of 0000-001F) 2140 - 21FF RAM block 1 (mirror of 0140-01FF) 2800 - 2FFF Mirror of 1800-27FF 3000 - 37FF Mirror of 1800-27FF 3800 - 3FFF Mirror of 1800-27FF 4000 - FFFF Cartridge address space F000 - FFFF BIOS ROM Note: F000-FFFF can be switched between either the cartridge or the bios ROM Note: The mirroring of sections of the memory map is pretty complex and I am not sure if this is 100% correct Maria addresses: 0020 - Background color 0021 - Palette 0 color 1 0022 - Palette 0 color 2 0023 - Palette 0 color 3 0024 - Wait for Sync 0025 - Palette 1 color 1 0026 - Palette 1 color 2 0027 - Palette 1 color 3 0028 - Maria Status bit 7: 1 = VBLANK/0 = Not VBLANK 0029 - Palette 2 color 1 002A - Palette 2 color 2 002B - Palette 2 color 3 002C - Display List List pointer high 002D - Palette 3 color 1 002E - Palette 3 color 2 002F - Palette 3 color 3 0030 - Display List List pointer low 0031 - Palette 4 color 1 0032 - Palette 4 color 2 0033 - Palette 4 color 3 0034 - Character base address 0035 - Palette 5 color 1 0036 - Palette 5 color 2 0037 - Palette 5 color 3 0038 - Reserved for future expansion 0039 - Palette 6 color 1 003A - Palette 6 color 2 003B - Palette 6 color 3 003C - MARIA control Bit 7: Color Kill 0 = Normal Color/1 = No Color Bit 6,5: DMA control 0 = Test A (DO NOT USE) 1 = Test B (DO NOT USE) 2 = Normal DMA 3 = No DMA (Note: The Atari MARIA documentation says to NOT USE test mode A or B since it can damage the 7800's hardware) Bit 4: Character Width 0 = Two byte characters/1 = Single byte characters Bit 3: Border Control 0 = Background color border / 1 = Black border Bit 2: Kangaroo mode 0 = Transparency / 1 = Kangaroo mode Bit 1,0: Read mode 0 = 160x2 or 160x4 1 = Not used 2 = 320B or 320D 3 = 320A or 320C 003D - Palette 7 color 1 003E - Palette 7 color 2 003F - Palette 7 color 3