INES Mapper 195: Difference between revisions

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(Chaos World is Mapper 176.)
(incorporate NewRisingSun's findings)
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{{DEFAULTSORT:195}}[[Category:iNES Mappers]][[Category:MMC3 with CHR ROM and CHR RAM]][[Category:Mappers with scanline IRQs]]
{{DEFAULTSORT:195}}[[Category:iNES Mappers]][[Category:MMC3 with CHR ROM and CHR RAM]][[Category:Mappers with scanline IRQs]]
[[iNES Mapper 195]], like mappers [[iNES Mapper 074|74]], [[iNES Mapper 119|119]], [[iNES Mapper 191|191]], [[iNES Mapper 192|192]], and [[iNES Mapper 194|194]], replaces some pages of CHR in this MMC3-like mapper with RAM.
[[iNES Mapper 195]] describes Waixing's FS303 board, which has an MMC3 clone and a GAL that can dynamically change which CHR banks are mapped to RAM.


195 specifically replaces pages 0-3 with RAM. It seems to be used at least for the Waixing pirate ports ''Columbus - Ougon no Yoake'', ''Captain Tsubasa Vol 2''.
The game writes, via the PPU, to specific CHR banks in order to select both which and how many CHR banks are mapped to RAM instead of ROM.


This information was derived from the Nestopia-1.4.0 and FCEUX-2.1.5 sources.
Writes to CHR ROM in multiples of 1 KiB:
CHRB~[1Z.D L.L.]
      || | |  |
      |+-|-+--+--------------- Select first bank and size of CHR RAM:
      || |                      $80 = $28-$2B
      || |                      $82 = $00-$03
      || |                      $88 = $4C-$4F
      || |                      $8A = $64-$67
      || |                      $C0 = $46-$47
      || |                      $C2 = $7C-$7D
      || |                      $C8 = $0A-$0B
      || |                      $CA = only CHR ROM
      || +-------------------- If 1, ignore above and always enable CHR ROM / disable CHR RAM
      |+---------------------- Number of banks of CHR RAM, 0=4KiB, 1=2KiB
      +----------------------- Must be 1  


A [[NES 2.0]]-compliant image and emulator will treat mappers [[iNES Mapper 194|194]] and 195 the same; they both specify CHR-RAM pages start at 0 and contain no mirrors.
The following games are known to use this mapper:
Waixing's pirate ports of ''Columbus - Ougon no Yoake'', ''Captain Tsubasa Vol 2'', ''Sugoro Quest'', and ''Crystalis''.


Mappers [[iNES Mapper 252|252]] and [[iNES Mapper 253|253]], also used for Waixing's localizations, are similar but use a VRC4.
Mappers [[iNES Mapper 252|252]] and [[iNES Mapper 253|253]], also used for Waixing's localizations, are similar but use a VRC4.
See also: [https://forums.nesdev.org/viewtopic.php?p=240335#p240335 NewRisingSun's findings]

Revision as of 18:17, 1 July 2019

iNES Mapper 195 describes Waixing's FS303 board, which has an MMC3 clone and a GAL that can dynamically change which CHR banks are mapped to RAM.

The game writes, via the PPU, to specific CHR banks in order to select both which and how many CHR banks are mapped to RAM instead of ROM.

Writes to CHR ROM in multiples of 1 KiB: 

CHRB~[1Z.D L.L.]
      || | |  |
      |+-|-+--+--------------- Select first bank and size of CHR RAM:
      || |                      $80 = $28-$2B
      || |                      $82 = $00-$03
      || |                      $88 = $4C-$4F
      || |                      $8A = $64-$67
      || |                      $C0 = $46-$47
      || |                      $C2 = $7C-$7D
      || |                      $C8 = $0A-$0B
      || |                      $CA = only CHR ROM
      || +-------------------- If 1, ignore above and always enable CHR ROM / disable CHR RAM
      |+---------------------- Number of banks of CHR RAM, 0=4KiB, 1=2KiB
      +----------------------- Must be 1

The following games are known to use this mapper: Waixing's pirate ports of Columbus - Ougon no Yoake, Captain Tsubasa Vol 2, Sugoro Quest, and Crystalis.

Mappers 252 and 253, also used for Waixing's localizations, are similar but use a VRC4.


See also: NewRisingSun's findings

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