NES 2.0 Mapper 519

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.

Address latch

A~1... .... MDPP PPPP
            ||++-++++- 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, address when reading from $8000-$FFFF ANDed with $FFF0 and ORed with the DIP switch setting ($0-$F)
            +--------- PRG-ROM banking mode
                        0: NROM-128 (16 KiB, $8000-$BFFF mirrored at $C000-$FFFF)
                        1: NROM-256 (32 KiB, bit 0 ignored)

Data latch

Mask: $8000

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.