NES 2.0 Mapper 525: Difference between revisions

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(+url to PCB images)
(pretty certain these PCBs never contained a VRC2; if they had, there would have been no point in reimplementing the CHR bankswitching)
 
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NES 2.0 Mapper 525 is used for the Kaiser bootleg versions of ''Contra'' and 月風魔伝 (Getsu Fūma Den). It's a [[VRC2]] clone (with chip A0=CPU A0 chip A1=CPU A1, i.e. VRC2b, Mapper 23 Submapper 3) with non-nibblized CHR-ROM bank registers. Its UNIF board name is '''UNL-KS7021A'''.
{{DEFAULTSORT:525}}[[Category:Discrete logic mappers]]
NES 2.0 Mapper 525 is used for mapper hacks of VRC2-using games. Specific known games include Kaiser bootleg versions of ''Contra'' and 月風魔伝 (Getsu Fūma Den). Its UNIF board name is '''UNL-KS7021A'''.


==CHR-ROM Bank Registers ($B000-$B007)==
== Registers ==
Mask: Probably $F007
Mask: $F000
  $8000: [.... PPP.] - Select 16KiB PRG bank at $8000-$BFFF
  $9000: [.... ...M] - like VRC2, 0: Vertical Mirroring (PPU A10); 1: Horizontal Mirroring (PPU A11)
 
Mask: $F007
* $B000: Select 1 KiB CHR-ROM bank at PPU $0000-$03FF
* $B000: Select 1 KiB CHR-ROM bank at PPU $0000-$03FF
* $B001: Select 1 KiB CHR-ROM bank at PPU $0400-$07FF
* $B001: Select 1 KiB CHR-ROM bank at PPU $0400-$07FF
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* $B007: Select 1 KiB CHR-ROM bank at PPU $1C00-$1FFF
* $B007: Select 1 KiB CHR-ROM bank at PPU $1C00-$1FFF


==PRG/Mirroring Registers ($8000-$AFFF)==
== Hardware ==
See [[VRC2]].
The 7021A PCB contains a [[7400]], a [[7427]], a [[7432]], a [[7474]], a [[74139]], a [[74157]], a [[74174]], two [[74189]]s, and the two ROMs.


==Notes==
==Notes==
*PCB images and analysis: [https://forums.nesdev.org/viewtopic.php?f=9&p=258431#p258431 BBS]
* Getsu Fūma Den PCB images and analysis: [//forums.nesdev.org/viewtopic.php?t=21091 BBS]

Latest revision as of 21:42, 25 October 2020

NES 2.0 Mapper 525 is used for mapper hacks of VRC2-using games. Specific known games include Kaiser bootleg versions of Contra and 月風魔伝 (Getsu Fūma Den). Its UNIF board name is UNL-KS7021A.

Registers

Mask: $F000

 $8000: [.... PPP.] - Select 16KiB PRG bank at $8000-$BFFF
 $9000: [.... ...M] - like VRC2, 0: Vertical Mirroring (PPU A10); 1: Horizontal Mirroring (PPU A11)

Mask: $F007

  • $B000: Select 1 KiB CHR-ROM bank at PPU $0000-$03FF
  • $B001: Select 1 KiB CHR-ROM bank at PPU $0400-$07FF
  • $B002: Select 1 KiB CHR-ROM bank at PPU $0800-$0BFF
  • $B003: Select 1 KiB CHR-ROM bank at PPU $0C00-$0FFF
  • $B004: Select 1 KiB CHR-ROM bank at PPU $1000-$13FF
  • $B005: Select 1 KiB CHR-ROM bank at PPU $1400-$17FF
  • $B006: Select 1 KiB CHR-ROM bank at PPU $1800-$1BFF
  • $B007: Select 1 KiB CHR-ROM bank at PPU $1C00-$1FFF

Hardware

The 7021A PCB contains a 7400, a 7427, a 7432, a 7474, a 74139, a 74157, a 74174, two 74189s, and the two ROMs.

Notes

  • Getsu Fūma Den PCB images and analysis: BBS