FxROM
From Nesdev wiki
(Redirected from FKROM)
The generic designation FxROM refers to cartridge boards made by Nintendo that use the Nintendo MMC4 mapper.
The following FxROM boards are known to exist:
| Board | PRG ROM | PRG RAM | CHR |
|---|---|---|---|
| FJROM | 128, 256 KB | 8 KB | 16, 32, 64 KB ROM |
| FKROM | 128, 256 KB | 8 KB | 128 KB ROM |
Contents |
Overview
- PRG ROM size: up to 256 KB
- PRG ROM bank size: 16 KB
- PRG RAM: 8 KB plus optional battery
- CHR capacity: up to 128 KB ROM
- CHR bank size: 4 KB
- Nametable mirroring: Controlled by mapper
- Subject to bus conflicts: No
Solder Pad config
Battery backup
- PRG RAM with data retention : 'SL' disconnected, D1, D2, R1, R2, R3 present.
- PRG RAM without data retention : 'SL' connected, D1, D2, R1, R2, R3 not present.
On the FKROM board, battery backup appears to be compulsary unless there is a hidden solder bad below the M1026 chip.
Hardware
The FKROM board uses a Microchip M1026 chip dedicated to safe battery backup. It's the only Nintendo boards to use a specific chip dedicated to safe battery backup.
