INES Mapper 114: Difference between revisions
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iNES Mapper 114 is used for an [[MMC3]]-clone-bearing board with scrambled register addresses and indices, a 256 KiB outer CHR-ROM bank register, | iNES Mapper 114 is used for an [[MMC3]]-clone-bearing board with scrambled register addresses and indices, a 256 KiB outer CHR-ROM bank register, | ||
and an NROM-like PRG-ROM register that can override the MMC3 clone's PRG-ROM bank. | and an NROM-like PRG-ROM register that can override the MMC3 clone's PRG-ROM bank. | ||
* ''Aladdin'' (SuperGame, not ''Super Aladdin'', and not to be confused with ''Aladdin'' from J.Y. Company) | |||
* ''The Lion King'' (SuperGame) | * ''The Lion King'' (SuperGame) | ||
* ''Pocohontos'' (Hosenkan, not to be confused with ''Pocahontas Part 2'' from SuperGame) | * ''Pocohontos'' (Hosenkan, not to be confused with ''Pocahontas Part 2'' from SuperGame) | ||
* ''Super Donkey Kong'' (Hosenkan) | * ''Super Donkey Kong'' (Hosenkan) | ||
=Registers= | =Registers= | ||
==NROM Override Register ($6000)== | ==NROM Override Register ($6000)== | ||
Mask: Probably $E001 | Mask: Probably $E001 | ||
Line 54: | Line 31: | ||
* IRQ behavior resembles that of the MMC3A, i.e. a latch value of zero disables the IRQ, on which ''Aladdin'' depends. | * IRQ behavior resembles that of the MMC3A, i.e. a latch value of zero disables the IRQ, on which ''Aladdin'' depends. | ||
* Previous descriptions of Mapper 114/182 claim that a write to address $C001 is equivalent to writing both to an MMC3's $C000 and $C001 registers, and that writing to $A001 has no effect. A comparison of ''Aladdin'' (Mapper 114) and the ''Super Aladdin'' (Mapper 4, by the same developer) however indicates a one-to-one mapping, provided that MMC3A-like IRQ behavior is enforced. | * Previous descriptions of Mapper 114/182 claim that a write to address $C001 is equivalent to writing both to an MMC3's $C000 and $C001 registers, and that writing to $A001 has no effect. A comparison of ''Aladdin'' (Mapper 114) and the ''Super Aladdin'' (Mapper 4, by the same developer) however indicates a one-to-one mapping, provided that MMC3A-like IRQ behavior is enforced. | ||
==MMC3-compatible registers== | |||
Address written MMC3 register meant | |||
--------------- ------------------- | |||
$8000 $A001 | |||
$8001 $A000 | |||
$A000 $8000 | |||
$A001 $C000 | |||
$C000 $8001 | |||
$C001 $C001 | |||
$E000 $E000 | |||
$E001 $E001 | |||
$8000 index written MMC3 register meant | |||
------------------- ------------------- | |||
0 0 | |||
1 3 | |||
2 1 | |||
3 5 | |||
4 6 | |||
5 7 | |||
6 2 | |||
7 4 | |||
=Similar Mappers= | =Similar Mappers= |
Revision as of 18:57, 23 May 2018
iNES Mapper 114 is used for an MMC3-clone-bearing board with scrambled register addresses and indices, a 256 KiB outer CHR-ROM bank register, and an NROM-like PRG-ROM register that can override the MMC3 clone's PRG-ROM bank.
- Aladdin (SuperGame, not Super Aladdin, and not to be confused with Aladdin from J.Y. Company)
- The Lion King (SuperGame)
- Pocohontos (Hosenkan, not to be confused with Pocahontas Part 2 from SuperGame)
- Super Donkey Kong (Hosenkan)
Registers
NROM Override Register ($6000)
Mask: Probably $E001 D~7654 3210 --------- M.S. BBBb | | ++++- Select 16 KiB PRG-ROM bank at CPU | | $8000-$BFFF and $C000-$FFFF | +------- 0: Do not replace bit 0 (NROM-128) | 1: Replace bit 0 with CPU A14 (NROM-256) +--------- 0: Use PRG bank from MMC3; ignore $6000 bits 0-3/5 1: Ignore PRG bank from MMC3; apply $6000 bits 0-3/5
Outer CHR-ROM Bank Register ($6001)
Mask: Probably $E001 D~7654 3210 --------- .... ...+- Select 256 KiB CHR-ROM bank at PPU $0000-$1FFF
Notes
- Unlike many similar mappers, the $600x registers are not connected to the MMC3 clone's WRAM interface and thus function regardless of whether WRAM is enabled or not.
- IRQ behavior resembles that of the MMC3A, i.e. a latch value of zero disables the IRQ, on which Aladdin depends.
- Previous descriptions of Mapper 114/182 claim that a write to address $C001 is equivalent to writing both to an MMC3's $C000 and $C001 registers, and that writing to $A001 has no effect. A comparison of Aladdin (Mapper 114) and the Super Aladdin (Mapper 4, by the same developer) however indicates a one-to-one mapping, provided that MMC3A-like IRQ behavior is enforced.
MMC3-compatible registers
Address written MMC3 register meant --------------- ------------------- $8000 $A001 $8001 $A000 $A000 $8000 $A001 $C000 $C000 $8001 $C001 $C001 $E000 $E000 $E001 $E001
$8000 index written MMC3 register meant ------------------- ------------------- 0 0 1 3 2 1 3 5 4 6 5 7 6 2 7 4
Similar Mappers
- INES Mapper 182 is a duplicate of Mapper 114. In fact, FCEUX explicitly reassigns Hosenkan's Mapper 182 ROMs to Mapper 114. Because Hosenkan's games make no use of the $6000-$6001 registers, other than writing zero to both of them on startup, some implementations (such as the EverDrive N8's) do not emulate the $600x registers.
- INES Mapper 115 has the same $6000 and $6001 registers, but does not scramble MMC3 register addresses and indices. Also, Mapper 115's IRQ behavior resembles that of the MMC3C, i.e. a latch value of zero causes an IRQ on every scanline, on which the Chinese version of 幽☆遊☆白書 Final (Yuu Yuu Hakusho Final) depends.
- INES Mapper 215 extends and moves $6000/$6001 to $5000/$5001, and makes the MMC3 register address and index scrambling pattern selectable via $5007.