iNES Mapper 134 denotes an MMC3-clone-based multicart PCB referred to alternatively as T4A54A, WX-KB4K, or BS-5652.
Mask: $E003 D~7654 3210 --------- LD.. C... || +---- CHR-ROM banking mode || 0: MMC3 (inner banks from $8000.0-$8000.5) || 1: CNROM (8 KiB inner bank from $6002) |+-------- CPU $8000-$FFFF mode | 0: PRG-ROM | 1: Read solder pad setting +--------- $6xxx Register Lock (except $6002.0-1) 0: unlocked 1: locked, further writes ignored until reset
Mask: $E003 D~7654 3210 --------- NcCC npPP |||| ||++- PRG A18..17 |||| |+--- Outer PRG Bank Size |||| | 0: 256 KiB, PRG A17 from MMC3 |||| | 1: 128 KiB, PRG A17 from $6001 bit 0 |||| +---- PRG A14 mode in NROM mode ($6001 bit 7=1) |||| 0: PRG A14=CPU A14 (NROM-256) |||| 1: PRG A14=MMC3 PRG A14 (NROM-128) ||++------ CHR A18..17 |+-------- Outer CHR Bank Size | 0: 256 KiB, CHR A17 from MMC3 | 1: 128 KiB, CHR A17 from $6001 bit 4 +--------- PRG-ROM banking mode 0: MMC3 1: NROM
In NROM mode, the MMC3 clone's CPU A13 and A14 inputs are held low, so that MMC3 register 6 applies to the entire CPU $8000-$FFFF range, with PRG A13 substituted by CPU A13 and PRG A14 subject to $6001.3.
Mask: $E003
Contains the 8 KiB CHR-ROM bank if $6000.3=1, masked to 128 or 256 KiB according to $6000.6. Bits 0-1 respond even if the "Lock" bit is set, while changes to bits 2-7 will be ignored if the "Lock" bit has been set.
Mask: $E003
Mask: $E001 See MMC3.
Categories: MMC3-like mappers, Mappers with scanline IRQs, Multicart mappers, INES Mappers