NES 2.0 Mapper 429: Difference between revisions
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[[NES 2.0 Mapper 429]] is for Milowork FCFC1 flash cartridge. There is some doujin game in progress using this mapper. | [[NES 2.0 Mapper 429]] is for Milowork FCFC1 flash cartridge (in A mode). There is some doujin game in progress using this mapper. | ||
== Overview == | == Overview == | ||
| Line 7: | Line 7: | ||
* CHR capacity: 32 KB RAM, optional battery-backup or FeRAM | * CHR capacity: 32 KB RAM, optional battery-backup or FeRAM | ||
* CHR bank size: 8 KB | * CHR bank size: 8 KB | ||
* Nametable [[mirroring]]: vertical or horizontal selected by switch | * Nametable [[mirroring]]: vertical or horizontal selected by switch, or fixed | ||
* Subject to [[bus conflict]]s: No | * Subject to [[bus conflict]]s: No | ||
| Line 18: | Line 18: | ||
|| ||++- Select 8 KB CHR RAM bank for PPU $0000-$1FFF, initial bank 0 | || ||++- Select 8 KB CHR RAM bank for PPU $0000-$1FFF, initial bank 0 | ||
++-++--- Select 32 KB PRG ROM bank for CPU $8000-$FFFF, initial bank 1 | ++-++--- Select 32 KB PRG ROM bank for CPU $8000-$FFFF, initial bank 1 | ||
== FCFC1 Details == | |||
* The A mode of FCFC1 has compatibility with [[CNROM]]/[[GxROM]], but the compatibility is fragile, some games will switch back to the page where the firmware is located, causing problems such as crashes. | |||
* The B mode of FCFC1 is a [[BNROM]]/[[AxROM]] with initial bank 4 and no [[bus conflict]], and has compatibility with [[NROM]]/[[UNROM]]. | |||
* To simplify the circuit implementation, the actual location of the page in ROM is shuffled. | |||
* It is recommended to save the preserved data to a page other than 0 of CHR RAM, as this avoids being overwritten by the kazzo programming process, and it can also make the bank selection play a role similar to the WRAM lock bit. | |||
* Some FCFC1 sold as game carriers do not have switches, or the switches do not have the W position. These FCFC1 are not compatible with kazzo. | |||
{| class="wikitable" | |||
! Register value causes error !! CNROM (A) !! GxROM (A) !! NROM (B) (Except using CHR RAM) | |||
|- | |||
| Firmware 2.1 and before || xxx1xx || xxx1xx || xxx1xx | |||
|- | |||
| Firmware 2.2 and after || xx01xx || xx01xx || xx01xx | |||
|} | |||
Revision as of 08:27, 13 May 2022
NES 2.0 Mapper 429 is for Milowork FCFC1 flash cartridge (in A mode). There is some doujin game in progress using this mapper.
Overview
- PRG ROM size: 512 KB
- PRG ROM bank size: 32 KB
- PRG RAM: None
- CHR capacity: 32 KB RAM, optional battery-backup or FeRAM
- CHR bank size: 8 KB
- Nametable mirroring: vertical or horizontal selected by switch, or fixed
- Subject to bus conflicts: No
Registers
Bank select ($8000-$FFFF)
7 bit 0 ---- ---- xxPP PPCC || |||| || ||++- Select 8 KB CHR RAM bank for PPU $0000-$1FFF, initial bank 0 ++-++--- Select 32 KB PRG ROM bank for CPU $8000-$FFFF, initial bank 1
FCFC1 Details
- The A mode of FCFC1 has compatibility with CNROM/GxROM, but the compatibility is fragile, some games will switch back to the page where the firmware is located, causing problems such as crashes.
- The B mode of FCFC1 is a BNROM/AxROM with initial bank 4 and no bus conflict, and has compatibility with NROM/UNROM.
- To simplify the circuit implementation, the actual location of the page in ROM is shuffled.
- It is recommended to save the preserved data to a page other than 0 of CHR RAM, as this avoids being overwritten by the kazzo programming process, and it can also make the bank selection play a role similar to the WRAM lock bit.
- Some FCFC1 sold as game carriers do not have switches, or the switches do not have the W position. These FCFC1 are not compatible with kazzo.
| Register value causes error | CNROM (A) | GxROM (A) | NROM (B) (Except using CHR RAM) |
|---|---|---|---|
| Firmware 2.1 and before | xxx1xx | xxx1xx | xxx1xx |
| Firmware 2.2 and after | xx01xx | xx01xx | xx01xx |
