NES 2.0 Mapper 512: Difference between revisions

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== Registers ==
== Registers ==
Mask: $E011
Mask: $E011
     $8000, $8001, $A000, $A001, $C000, $C001, $E000, $E001; addresses where CPU A4 is low: As normal MMC3. Note that the PRG and CHR banks are limited to a 128 KiB inner bank.
     $8000, $8001, $A000, $A001, $C000, $C001, $E000, $E001: As normal MMC3.
Mask: unknown, but probably $C100
Mask: unknown, but probably $C100
  $4100: Set CHR and VRAM mode
  $4100: Set CHR and VRAM mode

Revision as of 10:54, 31 December 2017

NES 2.0 Mapper 512 is used for 中國大亨 (Zhōngguó Dàhēng, often incorrectly rendered in Japanese as Chūgoku Taitei), a Chinese board game similar to Game of the Goose. It uses an MMC3 clone with both CHR-ROM and at least 4 KiB of CHR-RAM, 4 KiB of additional VRAM, plus 8 KiB of battery-backed WRAM at CPU $6000-&7FFF.

Registers

Mask: $E011

   $8000, $8001, $A000, $A001, $C000, $C001, $E000, $E001: As normal MMC3.

Mask: unknown, but probably $C100

$4100: Set CHR and VRAM mode
        0: CHR-ROM, CIRAM with MMC3-determined mirroring
        1: CHR-ROM, Cartridge VRAM
        2: CHR-RAM, CIRAM with MMC3-determined mirroring
        3: Seemingly identical to 2

The game uses four pages of cartridge VRAM for the main game board, plus the two pages of CIRAM for the status bar, for a total of six nametable pages. While the fact that cartridge VRAM and CHR-RAM cannot be enabled at the same time might suggest that the same 4 KiB of RAM are used for both purposes, such is not the case, as the game board is expected to retain its content while Chinese characters are written into CHR-RAM.