The generic designation SxROM refers to cartridge boards made by Nintendo that use the Nintendo MMC1 mapper.
The following SxROM boards are known to exist:
| Board | PRG ROM | PRG RAM | CHR | Comments |
|---|---|---|---|---|
| SAROM | 64 KB | 8 KB | 16 / 32 / 64 KB ROM | NES only |
| SBROM | 64 KB | 16 / 32 / 64 KB ROM | NES only | |
| SCROM | 64 KB | 128 KB ROM | NES only | |
| SC1ROM | 64 KB | 128 KB ROM | Uses 7432 for 28-pin CHR ROM | |
| SEROM | 32 KB | 16 / 32 / 64 KB ROM | ||
| SFROM | 128 / 256 KB | 16 / 32 / 64 KB ROM | ||
| SF1ROM | 256 KB | 64 KB ROM | PRG uses standard 32-pin EPROM pinout | |
| SFEXPROM | 256 KB | 64 KB ROM | Patches PRG at runtime to correct a bad mask ROM run. | |
| SGROM | 128 / 256 KB | 8 KB RAM/ROM | ||
| SHROM | 32 KB | 128 KB ROM | NES only | |
| SH1ROM | 32 KB | 128 KB ROM | Uses 7432 for 28-pin CHR ROM | |
| SIROM | 32 KB | 8 KB | 16 / 32 / 64 KB ROM | Japan Only |
| SJROM | 128 / 256 KB | 8 KB | 16 / 32 / 64 KB ROM | |
| SKROM | 128 / 256 KB | 8 KB | 128 KB ROM | |
| SLROM | 128 / 256 KB | 128 KB ROM | ||
| SL1ROM | 64 / 128 / 256 KB | 128 KB ROM | Uses 7432 for 28-pin CHR ROM | |
| SL2ROM | 128 / 256 KB | 128 KB ROM | CHR uses standard 32-pin EPROM pinout | |
| SL3ROM | 256 KB | 128 KB ROM | Uses 7432 for 28-pin CHR ROM | |
| SLRROM | 128 / 256 KB | 128 KB ROM | Difference from SLROM unknown | |
| SMROM | 256 KB | 8 KB RAM | Japan Only | |
| SNROM | 128 / 256 KB | 8 KB | 8 KB RAM/ROM | |
| SOROM | 128 / 256 KB | 16 KB | 8 KB RAM/ROM | |
| STROM | Not MMC1, actually NROM | |||
| SUROM | 512 KB | 8 KB | 8 KB RAM/ROM | |
| SXROM | 128 / 256 / 512 KB | 32 KB | 8 KB RAM/ROM | Japan Only |
| SZROM | 128 / 256 KB | 16 KB | 16-64 KB ROM | Japan Only |
The below pertains to SAROM, SJROM, SKROM, SNROM, SUROM, and SXROM boards only:
Even if the SOROM and SZROM boards utilizes a battery, it is connected to only one PRG RAM chip. The first RAM chip will not retain its data, but the second one will.
The SUROM, SOROM, and SXROM boards are extensions of SNROM, which has CHR RAM and PRG RAM. Because CHR RAM doesn't need bankswitching, these boards use the CHR bank select lines to switch different things:
In these scenarios, however, both CHR bank registers must be set to the same value (or the CHR bank size must be set to 8KB), or the PRG ROM/RAM will be bankswitched as the PPU renders, causing disastrous results.
Categories: Nintendo licensed mappers