INES Mapper 219

iNES Mapper 219 is used for the 卡聖 (Kǎshèng) A9461 MMC3-clone-bearing board, used by:

• Toy Story
• Super 1997 4-in-1

Mode Register ($8002)

Mask: $E003

7654 3210
---------
CPMR RRRR
||++-++++-*Select bank register number (0-7 in MMC3 mode, $08-$26 in Extended mode)
||+------- Select mode
||          0: MMC3 mode
||          1: Extended mode
|+--------*1: PRG A14 inversion in MMC3 mode
+---------*1: CHR A12 inversion in MMC3 mode

* Same as $8000

MMC3 mode registers ($8000-$FFFF)

Mask: $E001

$A000, $A001, $C000, $C001, $E000, $E001: As on regular MMC3.

MMC3 Bank Register Index ($8000)/Data ($8001)

Mask: $E001. Used only if $8002 bit 5=0, see MMC3. Note that PRG-ROM and CHR-ROM banks are masked to 128 KiB.

Extended PRG-ROM Bank Index ($8000)/Data ($8001)

Mask: $E001. Used only if $8002 bit 5=1.

$8000/$8002 value:

D~7654 3210
  ---------
  ..10 .RRR
        +++- 6: Select 8 KiB PRG-ROM bank at CPU $8000-$9FFF
             5: Select 8 KiB PRG-ROM bank at CPU $A000-$BFFF
             4: Select 8 KiB PRG-ROM bank at CPU $C000-$DFFF 
             3: Select 8 KiB PRG-ROM bank at CPU $E000-$FFFF

$8001 value:

D~7654 3210
  ---------
  ..BB BB..
    ++-++--- Bits 0-3 (reversed order) of 8 KiB PRG-ROM bank number

CHR-ROM Bank Number Latch Index ($8000)/Data ($8001)

Mask: $E001. Used only if $8002 bit 5=1.

$8000/$8002 value:

D~7654 3210
  ---------
  ..00 1..0
or
D~7654 3210
  ---------
  ..01 ...0

$8001 value:

D~7654 3210
  ---------
  .... .654
        +++- Bits 4-6 OR'd with next CHR-ROM switch's data

CHR-ROM Pseudo 2 KiB switch Index ($8000)/Data ($8001)

Mask: $E001. Used only if $8002 bit 5=1.

$8000/$8002 value:

D~7654 3210
  ---------
  ..00 1RR1
        ++-- Select CHR-ROM address range to switch
         |    0: PPU $0000-$03FF
         |    1: PPU $0400-$07FF
         |    2: PPU $0800-$0BFF
         |    3: PPU $0C00-$0FFF
         +-- OR'd with Bit 0 of CHR-ROM bank data

$8001 value:

D~7654 3210
  ---------
  BBBB BBB.
  ++++-+++-- Bits 0-6 of 1 KiB CHR-ROM bank number at PPU address selected via $8000/$8002.

The value is OR'd with bit 1 SHR 1 of the value written to $8000, then OR'd with bits 0-2 SHL 4 of the value written to the CHR-ROM latch.

CHR-ROM 1 KiB switch Index ($8000)/Data ($8001)

Mask: $E001. Used only if $8002 bit 5=1.

$8000/$8002 value:

D~7654 3210
  ---------
  ..01 RR.1
       ++--- Select CHR-ROM address range to switch
              0: PPU $1000-$13FF
              1: PPU $1400-$17FF
              2: PPU $1800-$1BFF
              3: PPU $1C00-$1FFF

$8001 value:

D~7654 3210
  ---------
  BBBB BBB.
  ++++-+++-- Bits 0-6 of 1 KiB CHR-ROM bank number at PPU address selected via $8000/$8002.

The value is OR'd with bits 0-2 SHL 4 of the value written to the CHR-ROM latch.

Outer Bank Bit 0 ($5002)

Mask: $5003

D~7654 3210
  ---------
  .... ...B
          +- Bit 0 of 128 KiB outer PRG-ROM and CHR-ROM bank

Outer Bank Bit 1 ($5003)

Mask: $5003

D~7654 3210
  ---------
  ..B. ....
    +------- Bit 1 of 128 KiB outer PRG-ROM and CHR-ROM bank

Sources

• FCEUX implementation
• Nestopia's implementation