INES Mapper 031: Difference between revisions

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* [https://www.mesen.ca/ Mesen] 0.9.0
* [https://www.mesen.ca/ Mesen] 0.9.0
* [https://www.qmtpro.com/~nes/nintendulator/ Nintendulator] 0.975
* [https://www.qmtpro.com/~nes/nintendulator/ Nintendulator] 0.975
* [https://openemu.org/ OpenEmu] (FCEU core) 2.0.3
* [http://forums.nesdev.org/viewtopic.php?t=6928 puNES] 0.84
* [http://forums.nesdev.org/viewtopic.php?t=6928 puNES] 0.84



Revision as of 21:16, 23 August 2018

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:

Overview

  • PRG ROM size: Up to 1024 kB
  • PRG ROM bank size: 4 kB
  • PRG RAM: None
  • CHR capacity: 8 kB RAM/ROM
  • CHR bank size: Not bankswitched
  • Nametable mirroring: horizontal or vertical, hard wired.
  • Subject to bus conflicts: No

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

Cartridges: