iNES Mapper 091 was used by the original release of Super Fighter III from an unknown publisher, but is more commonly known by a clone board from J.Y. Company.
INES Mapper 091 submapper table
|
Submapper # |
Board |
Games
|
0 |
JY830623C |
Street Fighter 3, Mortal Kombat II, Dragon Ball Z 2, Mario & Sonic 2
|
0 |
YY840238C |
1995 Super HIK 4-in-1 (JY-016), 1995 Super HiK 4-in-1 (JY-017)
|
1 |
EJ-006-1 |
Super Fighter III
|
Submapper 0 has a PA12-based IRQ counter and hard-wired mirroring; submapper 1 an M2-based IRQ counter and selectable mirroring.
Contents
- 1 Banks
- 2 Registers
- 2.1 CHR-ROM Bank Select ($6000-$6003, write)
- 2.2 Nametable Mirroring Select ($6004-$6005, write, submapper 1 only)
- 2.3 IRQ Counter Register ($6006-$6007, write, submapper 1 only)
- 2.4 PRG-ROM Bank Select ($7000-$7001, write)
- 2.5 IRQ Stop/Acknowledge ($7006, write)
- 2.6 IRQ Start/Reset ($7007, write)
- 2.7 Outer Bank register ($8000-$9FFF, write, submapper 0 only)
- 3 Notes
Banks
- CPU $8000-$9FFF: 8 KiB switchable PRG-ROM bank
- CPU $A000-$BFFF: 8 KiB switchable PRG-ROM bank
- CPU $C000-$FFFF: 16 KiB PRG-ROM bank, hard-wired to last bank
- PPU $0000-$07FF: 2 KiB switchable CHR-ROM bank
- PPU $0800-$0FFF: 2 KiB switchable CHR-ROM bank
- PPU $1000-$17FF: 2 KiB switchable CHR-ROM bank
- PPU $1800-$1FFF: 2 KiB switchable CHR-ROM bank
Registers
CHR-ROM Bank Select ($6000-$6003, write)
Mask: $F003/$F007 (submapper 0/1)
- $6000: Select 2 KiB CHR-ROM bank at PPU $0000-$07FF
- $6001: Select 2 KiB CHR-ROM bank at PPU $0800-$0FFF
- $6002: Select 2 KiB CHR-ROM bank at PPU $1000-$17FF
- $6003: Select 2 KiB CHR-ROM bank at PPU $1800-$1FFF
Nametable Mirroring Select ($6004-$6005, write, submapper 1 only)
Mask: $F007
- $6004: Select horizontal mirroring, value ignored
- $6005: Select vertical mirroring, value ignored
IRQ Counter Register ($6006-$6007, write, submapper 1 only)
Mask: $F007
- $6006: Set IRQ Counter LSB
- $6007: Set IRQ Counter MSB
PRG-ROM Bank Select ($7000-$7001, write)
Mask: $F003/$F007 (submapper 0/1)
- $7000: Select 8 KiB PRG-ROM bank at CPU $8000-$9FFF
- $7001: Select 8 KiB PRG-ROM bank at CPU $A000-$BFFF
IRQ Stop/Acknowledge ($7006, write)
Mask: $F003 (submapper 0)/$F007 (submapper 1)
Value is ignored..
IRQ Start/Reset ($7007, write)
Mask: $F003/$F007 (submapper 0/1)
Value is ignored.
Outer Bank register ($8000-$9FFF, write, submapper 0 only)
Mask: unknown
A~FEDC BA98 7654 3210
-------------------
.... .... .... .PPC
||+- Select outer 512 KiB CHR-ROM bank (CHR A19)
++-- Select outer 128 KiB PRG-ROM bank (PRG A17-A18)
Notes
- Submapper 0: the IRQ counter is a binary counter clocked by PPU A12, and simply counts a fixed number of 64 unfiltered rises of PPU A12.
- Submapper 1: the IRQ counter is a binary counter clocked by the M2 signal with a factor of 5/4, meaning counting down by five every fourth M2 cycle.
- Submapper 1's Super Fighter III runs a hardware test when resetting with Select+Start+B pressed. The test exists in J.Y. Company's hacked versions as well, but was not adjusted for the simpler hardware and thus will fail some tests.
- The commonly available ROM image of Super Fighter III is a mapper hack for INES Mapper 197.
Categories: Mappers with fixed-timing scanline IRQs, INES Mappers