iNES Mapper 243 denotes the Sachen SA-020A circuit board. Using an eight-register ASIC with a fake "74LS374N" marking, it supports up to 128 KiB PRG-ROM, and 128 KiB of CHR-ROM. It is used for only one game, 美女拳 - Honey Peach (SA-006).
Mask: $C101
D~7654 3210
---------
.... .RRR
+++- Select register number (Rx)
Mask: $C101
D~7654 3210
---------
.... .RRR
+++- Register data
D~7654 3210
---------
.... ...A R2: CHR A13
.... ...B R4: CHR A14
.... ..PP R5: PRG A16..A15
.... ..DC R6: CHR A16..A15
... .MM. R7: Nametable mirroring
0: S0-S0-S0-S1 (lower right unique, or vertically-flipped L)
1: Horizontal
2: Vertical
3: Single-screen, page 1
Registers 0, 1, and 3 have no external effect. All three bits in all eight registers are fully implemented and can be read from and written to.
The SA-150 PCB, denoted by INES Mapper 150, connects the same ASIC differently, changing the meaning of the CHR-bank-related register bits.
Categories: Mappers using $4020-$5FFF, INES Mappers