View source for INES Mapper 187

{{DEFAULTSORT:187}}[[Category:MMC3-like mappers]][[Category:Mappers using $4020-$5FFF]][[Category:Mappers with scanline IRQs]]
iNES Mapper 187 is used for the 卡聖 (Kǎshèng) A98402 and similar boards, an [[MMC3]]-clone-bearing board with an NROM-like PRG-ROM register that can override the MMC3 clone's PRG-ROM bank, and supports 512 KiB of CHR-ROM. Used by:
* ''Street Fighter Zero 2'' (Kǎshèng/Hummer Team, not ''Street Fighter Zero 2 '97'')
* ''The King of Fighters '96'' (Kǎshèng/Hummer Team)

=Registers=
==NROM Override Register ($5000)==
 Mask: Unknown, probably $F000
 
 D~7654 3210
   ---------
   M.NB BBb.
   | |+-+++-- Select 16 KiB PRG-ROM bank at CPU
   | |        $8000-$BFFF and $C000-$FFFF
   | +------- 0: Do not replace bit 1 (NROM-128)
   |          1: Replace bit 1 with CPU A14 (NROM-256)
   +--------- 0: Use PRG bank from MMC3; ignore $5000 bits 1-4/5
              1: Ignore PRG bank from MMC3; apply $5000 bits 1-4/5

==Protection Read ($5000-$5FFF)==
Mask: Unknown

The actual values that are returned are unknown; ''The King of Fighters '96'' reads from here and only expects bit 7 of the value being returned to be set.

==CHR A18 Control ($8000-$9FFF, even)==
 Mask: $E001
 
 D~7654 3210
   ---------
   M... ....
   +--------- Select CHR A18 Mode
               0: CHR A18=inverted PPU A12
               1: CHR A18=PPU A12

Basically, either sprites or background tiles will come from the the second 256 KiB of CHR-ROM. Note that setting bit 7 will still also activate the MMC3 clone's CHR A12 inversion.

==MMC3-compatible registers ($8000-$FFFF)==
Mask: $E001, see [[MMC3]].

=Errata=
* GoodNES 3.23b has several [[INES Mapper 121]] and [[INES Mapper 189]] images erroneously set to 187.

=Similar Mappers=
* iNES Mappers [[INES Mapper 115|115]] and [[INES Mapper 123|123]] have similar NROM override registers, with Mapper 123's bits arranged a bit differently.
* iNES Mapper [[INES Mapper 121|121]] has the same CHR A18 behavior, drops the NROM override register, and adds more complex protection.