NES 2.0 Mapper 519: Difference between revisions

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[[Category:Multicart mappers]]NES 2.0 Mapper 519 is used for Chinese-language multicarts designated by the UNIF board name '''UNL-EH8813A'''. It latches both the CPU address and data buses.
[[Category:Multicart mappers]]NES 2.0 Mapper 519 is used for Chinese-language multicarts designated by the UNIF board name '''UNL-EH8813A'''. It latches both the CPU address and data buses.


  A~[1... .... MDPP PPPP] D~[CCCC CCCC]
  A~[1... ...L pDPP PPPP] D~[MCCC CCCC]
              |||| ||||    ++++-++++-- Select 8 KiB CHR-ROM bank at PPU $0000-$1FFF
            | |||| ||||    |||| ||++-- Select Inner 8 KiB CHR-ROM bank at PPU $0000-$1FFF
              ||++-++++---------------- Select 16 KiB PRG-ROM bank at CPU $8000-$BFFF/$C000-$FFFF
            | |||| ||||    |+++-++---- Select Outer 32 KiB CHR-ROM bank at PPU $0000-$1FFF (*)
              |+----------------------- Read DIP switch mode
            | |||| ||||    +---------- Select Nametable mirroring type (0=Vertical, 1=Horizontal) (*)
              |                          0: Disabled, reads from $8000-$FFFF normal
            | ||++-++++---------------- Select 16 KiB PRG-ROM bank at CPU $8000-$BFFF/$C000-$FFFF (*)
              |                          1: Enabled, when reading from $8000-$FFFF:
            | |+----------------------- Read DIP switch mode (*)
              |                              Bitwise AND address with $FFF0 and OR with the DIP switch setting ($0-$F)
            | |                          0: Disabled, reads from $8000-$FFFF normal
              +------------------------ PRG-ROM banking mode
            | |                          1: Enabled, when reading from $8000-$FFFF:
                                          0: NROM-128 (16 KiB, $8000-$BFFF mirrored at $C000-$FFFF)
            | |                              Bitwise AND address with $FFF0 and OR with the DIP switch setting ($0-$F)
                                          1: NROM-256 (32 KiB, bit 0 ignored)
            | +------------------------ PRG-ROM banking mode (*)
 
            |                            0: NROM-256 (32 KiB, bit 0 ignored)
All known ROM images always use Vertical mirroring, so it's not known whether mirroring is hardwired, or whether horizontal mirroring could be set using a so far unknown bit.
            |                            1: NROM-128 (16 KiB, $8000-$BFFF mirrored at $C000-$FFFF)
            +-------------------------- 1=Lock all fields marked (*)


[[iNES Mapper 227]] appears to also have the same "DIP switch" that can override LSBs of address so that the multicart can detect which variant it's pretending to be.
[[iNES Mapper 227]] appears to also have the same "DIP switch" that can override LSBs of address so that the multicart can detect which variant it's pretending to be.

Revision as of 10:32, 3 April 2018

NES 2.0 Mapper 519 is used for Chinese-language multicarts designated by the UNIF board name UNL-EH8813A. It latches both the CPU address and data buses. 

A~[1... ...L pDPP PPPP] D~[MCCC CCCC]
           | |||| ||||     |||| ||++-- Select Inner 8 KiB CHR-ROM bank at PPU $0000-$1FFF
           | |||| ||||     |+++-++---- Select Outer 32 KiB CHR-ROM bank at PPU $0000-$1FFF (*)
           | |||| ||||     +---------- Select Nametable mirroring type (0=Vertical, 1=Horizontal) (*)
           | ||++-++++---------------- Select 16 KiB PRG-ROM bank at CPU $8000-$BFFF/$C000-$FFFF (*)
           | |+----------------------- Read DIP switch mode (*)
           | |                           0: Disabled, reads from $8000-$FFFF normal
           | |                           1: Enabled, when reading from $8000-$FFFF:
           | |                               Bitwise AND address with $FFF0 and OR with the DIP switch setting ($0-$F)
           | +------------------------ PRG-ROM banking mode (*)
           |                             0: NROM-256 (32 KiB, bit 0 ignored)
           |                             1: NROM-128 (16 KiB, $8000-$BFFF mirrored at $C000-$FFFF)
           +-------------------------- 1=Lock all fields marked (*)

iNES Mapper 227 appears to also have the same "DIP switch" that can override LSBs of address so that the multicart can detect which variant it's pretending to be.

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