INES Mapper 219: Difference between revisions

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{{DEFAULTSORT:219}} [[Category:iNES Mappers]] [[Category:Mappers with scanline IRQs]]
{{DEFAULTSORT:219}} [[Category:iNES Mappers]] [[Category:Mappers with scanline IRQs]]
[[iNES Mapper 219]], also known as "UNL A9746", is sort of like an [[MMC3]] without fixed banks, and some odd CHR banking.
iNES Mapper 219 is used for the 卡聖 (Kǎshèng) A9461 MMC3-clone-bearing board, used by:
==Banking==
* ''Toy Story''
*PRG: 4x8KiB (none fixed), 4 bits = 128KiB max
* ''Super 1997 4-in-1 (NT-8029)''
*CHR: 8x1KiB, 12 bits = 4MiB max


==Registers==
==Mode Register ($8002)==
  Mask: $E003
  Mask: $E003
$8000 Select Register 1
$8002 Select Register 2
$8001 Control Register
Whichever of $8000, $8002 is last written decides what $8001 writes do.
   
   
It appears to have [[MMC3#IRQ_latch_.28.24C000-.24DFFE.2C_even.29 | MMC3-like IRQ registers,]] as the implementation just falls through and uses those directly.
7654 3210
Mask $E001  
---------
  $C000 IRQ latch
CPMR RRRR
  $C001 IRQ reload
||++-++++-*Select bank register number (0-7 in MMC3 mode, $08-$26 in Extended mode)
  $E000 IRQ disable
||+------- Select mode
  $E001 IRQ enable
||          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, $23-$26)/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, $08-$1E, even)/Data ($8001)==
Mask: $E001. Used only if $8002 bit 5=1.
 
$8000 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, $09-$0F, odd)/Data ($8001)==
Mask: $E001. Used only if $8002 bit 5=1.
 
$8000 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, $11-$1F, odd)/Data ($8001)==
Mask: $E001. Used only if $8002 bit 5=1.
 
$8000 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


CHR banking is very odd. The following bits are ORed together:
The Outer Bank register must be initialized to $03 for the menu to appear.
Latch: CBA98765.... [write << 4]
Inner: .....7654321 [write >> 1]
and, if the bank is $0400 or $0C00, the least significant bit is further ORed with 1.
This has the effect of allowing consecutive writes to adjacent bank regs to get "sort of" a 2k bank.


{| class="wikitable"
==Note==
| $8000 write || $8002 write || bits || $8000 effect
This mapper gets hot and breaks down easily when using dumping devices.
|-
| $26 || - || ..PPPP.. || (reversed) bits of PRG bank $8000-$9FFF, central nibble only
|-
| $25 || - || ..PPPP.. || (reversed) bits of PRG bank $A000-$BFFF, central nibble only
|-
| $24 || - || ..PPPP.. || (reversed) bits of PRG bank $C000-$DFFF, central nibble only
|-
| $23 || - || ..PPPP.. || (reversed) bits of PRG bank $E000-$FFFF, central nibble only
|-
| - || $08-$1e(even) || CBA98765 || Outer CHR bit latch for any 1k bank, 8 bits
|-
| - || $09 || 7654321. || Inner 7 CHR bits for $0000-$03FF
|-
| - || $0B || 765432*. || Inner 7 CHR bits for $0400-$07FF (*least bit ORed to 1 regardless)
|-
| - || $0D || 7654321. || Inner 7 CHR bits for $0800-$0BFF
|-
| - || $0F || 765432*. || Inner 7 CHR bits for $0C00-$0FFF (*least bit ORed to 1 regardless)
|-
| - || $11 || 7654321. || Inner 7 CHR bits for $1000-$13FF
|-
| - || $15 || 7654321. || Inner 7 CHR bits for $1400-$17FF
|-
| - || $19 || 7654321. || Inner 7 CHR bits for $1800-$1BFF
|-
| - || $1D || 7654321. || Inner 7 CHR bits for $1C00-$1FFF
|}


==Sources==
==Sources==
*[https://sourceforge.net/p/fceultra/code/3320/tree/fceu/trunk/src/boards/a9746.cpp FCEUX implementation]
*[https://sourceforge.net/p/fceultra/code/3320/tree/fceu/trunk/src/boards/a9746.cpp FCEUX implementation]
*Nestopia's source does not appear to differ significantly.
*[https://github.com/rdanbrook/nestopia/blob/88d130fd083b9662ef49e8d5ef95513f4bb8759e/source/core/board/NstBoardUnlA9746.cpp Nestopia's implementation]

Latest revision as of 14:10, 25 March 2024

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

  • Toy Story
  • Super 1997 4-in-1 (NT-8029)

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, $23-$26)/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, $08-$1E, even)/Data ($8001)

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

$8000 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, $09-$0F, odd)/Data ($8001)

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

$8000 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, $11-$1F, odd)/Data ($8001)

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

$8000 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

The Outer Bank register must be initialized to $03 for the menu to appear.

Note

This mapper gets hot and breaks down easily when using dumping devices.

Sources

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