NES 2.0 Mapper 523

NES 2.0 Mapper 523 is used for the 晶科泰 (Jncota) re-release of the game 封神榜: 伏魔三太子 (Fēngshénbǎng: Fúmó Sān Tàizǐ), originally released by C&E on INES Mapper 246. It is basically identical to the Waixing FS005 board, except that ...

• Mirroring is hard-wired (to Horizontal in Fēngshénbǎng's case),
• CHR-ROM A10 is directly connected to PPU A10,
• CHR-ROM A11-A18 are connected to the MMC3 clone's CHR A10-A17 outputs,
• the MMC3 clone's PPU A10 input is connected to Ground.

With the MMC3 clone set to Extended MMC3 Mode, the bank registers at $8000 therefore change from their normal to the following meanings:

$0: Select 2 KiB CHR bank at PPU $0000-$07FF (or $1000-$17FF)
$1: Select 2 KiB CHR bank at PPU $0800-$0FFF (or $1800-$1FFF)
$2: Select 2 KiB CHR bank at PPU $1000-$17FF (or $0000-$07FF)
$3: No function
$4: Select 2 KiB CHR bank at PPU $1800-$1FFF (or $0800-$0FFF)
$5: No function
$6: Select 8 KiB PRG ROM bank at $8000-$9FFF (or $C000-$DFFF)
$7: Select 8 KiB PRG ROM bank at $A000-$BFFF
$8: Select 8 KiB PRG ROM bank at $C000-$DFFF (or $8000-$9FFF)
$9: Select 8 KiB PRG ROM bank at $E000-$FFFF
$A: No function
$B: No function