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 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.


==Address latch ==
  A~[1... ...L pDPP PPPP] D~[MCCC CCCC]
  A~1... .... MDPP PPPP
            | |||| ||||    |||| ||++-- 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, address when reading from $8000-$FFFF ANDed with $FFF0 and ORed with the DIP switch setting ($0-$F)
            | |+----------------------- Read DIP switch mode (*)
            +--------- PRG-ROM banking mode
            | |                           0: Disabled, reads from $8000-$FFFF normal
                        0: NROM-128 (16 KiB, $8000-$BFFF mirrored at $C000-$FFFF)
            | |                           1: Enabled, when reading from $8000-$FFFF:
                        1: NROM-256 (32 KiB, bit 0 ignored)
            | |                              Bitwise AND address with $FFF0 and OR with the DIP switch setting ($0-$F)
 
            | +------------------------ PRG-ROM banking mode (*)
==Data latch ==
            |                            0: NROM-256 (32 KiB, bit 0 ignored)
Mask: $8000
            |                            1: NROM-128 (16 KiB, $8000-$BFFF mirrored at $C000-$FFFF)
 
            +-------------------------- 1=Lock all fields marked (*)
7654 3210
---------
CCCC CCCC
++++-++++- Select 8 KiB CHR-ROM bank at PPU $0000-$1FFF
 
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.

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 (*)