NES 2.0 Mapper 519: Difference between revisions

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(combine the two latches; they're updated at the same moment)
(Irrelevant and unverified)
 
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[[Category:Multicart mappers]]NES 2.0 Mapper 519 is used for Chinese-language multicarts designed by the UNIF board name '''UNL-EH8813A'''. It latches both the CPU address and data buses.
{{DEFAULTSORT:519}}[[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.

Latest revision as of 11:19, 5 April 2021

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 (*)
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