INES Mapper 031: Difference between revisions
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'''iNES Mapper 031''' represents a mapper created to facilitate cartridge compilations of [[NSF]] music. It implements a common subset of the features used by NSFs. | {{Infobox_iNES_mapper | ||
|name=NSF subset | |||
|company=varies (homebrew) | |||
|boards=unknown (homebrew) | |||
|mapper=31 | |||
|complexity=CPLD | |||
|prgmax=1024K | |||
|prgpage=4K | |||
|chrmax=8K | |||
|chrpage=n/a | |||
|busconflicts=Not applicable | |||
}}'''iNES Mapper 031''' represents a mapper created to facilitate cartridge compilations of [[NSF]] music. It implements a common subset of the features used by NSFs. | |||
PRG-ROM is bankswitched in 8 x 4 kB banks from $8000-FFFF. These are controlled by registers at $5FF8-$5FFF like the NSF mapper. The high bank at $F000-FFFF is initialized to the last bank at power-on. | PRG-ROM is bankswitched in 8 x 4 kB banks from $8000-FFFF. These are controlled by registers at $5FF8-$5FFF like the NSF mapper. The high bank at $F000-FFFF is initialized to the last bank at power-on. | ||
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* ''ZENSF'' ([//forums.nesdev.org/viewtopic.php?f=6&t=17698 forum post]) | * ''ZENSF'' ([//forums.nesdev.org/viewtopic.php?f=6&t=17698 forum post]) | ||
* ''Test ROMs'' ([//forums.nesdev.org/viewtopic.php?f=3&t=13120 forum post]) | * ''Test ROMs'' ([//forums.nesdev.org/viewtopic.php?f=3&t=13120 forum post]) | ||
== Registers == | == Registers == | ||
Latest revision as of 04:15, 3 May 2022
| Company | varies (homebrew) |
| Complexity | CPLD |
| Boards | unknown (homebrew) |
| PRG ROM capacity | 1024K |
| PRG ROM window | 4K |
| PRG RAM capacity | None |
| CHR capacity | 8K |
| CHR window | n/a |
| Nametable mirroring | Fixed H or V, controlled by solder pads |
| Bus conflicts | Not applicable |
| IRQ | No |
| Audio | No |
| iNES mappers | 031 |
iNES Mapper 031 represents a mapper created to facilitate cartridge compilations of NSF music. It implements a common subset of the features used by NSFs.
PRG-ROM is bankswitched in 8 x 4 kB banks from $8000-FFFF. These are controlled by registers at $5FF8-$5FFF like the NSF mapper. The high bank at $F000-FFFF is initialized to the last bank at power-on.
There is no CHR banking, so it is recommended to use 8 kB CHR-RAM with this mapper.
As with BNROM and UxROM, there is no mirroring, CHR bank, or IRQ control; this mapper has hardwired H or V mirroring.
Examples:
- 2A03 Puritans (ROM)
- Famicompo Pico (ROMs)
- RNDM (info)
- EZNSF (forum post)
- ZENSF (forum post)
- Test ROMs (forum post)
Registers
PRG bank select $5000-$5FFF
address data
15 bit 0 7 bit 0
------------------- ---------
0101 .... .... .AAA PPPP PPPP
||| |||| ||||
||| ++++-++++- Select 4 kB PRG ROM bank at slot specified by write address.
+++------------ Specify 4 kB bank slot at: $8000 + (AAA * $1000)
The canonical write position for these registers is $5FF8-$5FFF, as used in NSFs.
At power on, the register at $5FFF is set to $FF. Startup code should be placed in the last bank. There is no change to this register on reset.
References
Emulator support
- BizHawk 1.11.2
- FCEUX 2.2.3
- MAME 0.162
- Mesen 0.9.0
- Nintendulator 0.975
- OpenEmu (FCEUX core) 2.0.3
- puNES 0.84
Cartridges:
- Everdrive N8 OS V14
- InfiniteNESLives Mapper 31 board
