VRC7: Difference between revisions

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m (Added way of making a universal VRC7 Cartridges that work with both games)
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* VRC7b uses A3 to select registers ($x008), used in ''Tiny Toon Adventures'' ('''Submapper 1''').
* VRC7b uses A3 to select registers ($x008), used in ''Tiny Toon Adventures'' ('''Submapper 1''').
* VRC7a uses A4 to select registers ($x010), used in ''Lagrange Point'' ('''Submapper 2''').
* VRC7a uses A4 to select registers ($x010), used in ''Lagrange Point'' ('''Submapper 2''').
In order to make a cartridge that is compatible with both games, an XOR gate could be placed with the inputs being A3 and A4, and the output going to the VRC7.


Although A5 is wired for sound registers on both ($x028, $x030), in the former board the ceramic resonator necessary for the sound hardware to work is missing.
Although A5 is wired for sound registers on both ($x028, $x030), in the former board the ceramic resonator necessary for the sound hardware to work is missing.

Revision as of 00:10, 6 October 2024

VRC7
Company Konami
Games 2 in NesCartDB
Complexity ASIC
Boards 352402, 353429
Pinout VRC7 pinout
PRG ROM capacity 512K
PRG ROM window 8Kx3 + 8K fixed
PRG RAM capacity 8K
PRG RAM window 8K fixed
CHR capacity 256K
CHR window 1Kx8
Nametable mirroring H, V, or 1, switchable
Bus conflicts No
IRQ Yes
Audio VRC7a only
iNES mappers 085

The Konami VRC7 is an ASIC mapper. It is assigned to iNES Mapper 085.

Example games:

  • Lagrange Point
  • Tiny Toon Adventures 2

See VRC7 pinout for chip pinout.

Banks

CPU

  • $6000-$7FFF: 8 KB PRG-RAM bank, fixed
  • $8000-$9FFF: 8 KB switchable PRG-ROM bank
  • $A000-$BFFF: 8 KB switchable PRG-ROM bank
  • $C000-$DFFF: 8 KB switchable PRG-ROM bank
  • $E000-$FFFF: 8 KB PRG-ROM bank, fixed to the last bank

PPU

  • $0000-$03FF: 1 KB switchable CHR-ROM bank
  • $0400-$07FF: 1 KB switchable CHR-ROM bank
  • $0800-$0BFF: 1 KB switchable CHR-ROM bank
  • $0C00-$0FFF: 1 KB switchable CHR-ROM bank
  • $1000-$13FF: 1 KB switchable CHR-ROM bank
  • $1400-$17FF: 1 KB switchable CHR-ROM bank
  • $1800-$1BFF: 1 KB switchable CHR-ROM bank
  • $1C00-$1FFF: 1 KB switchable CHR-ROM bank

If CHR-RAM is used instead of CHR-ROM, the banking feature is still functional.

Registers

There are two board variations:

  • VRC7b uses A3 to select registers ($x008), used in Tiny Toon Adventures (Submapper 1).
  • VRC7a uses A4 to select registers ($x010), used in Lagrange Point (Submapper 2).

In order to make a cartridge that is compatible with both games, an XOR gate could be placed with the inputs being A3 and A4, and the output going to the VRC7.

Although A5 is wired for sound registers on both ($x028, $x030), in the former board the ceramic resonator necessary for the sound hardware to work is missing.

PRG Select 0 ($8000)

7  bit  0
---------
..PP PPPP
  || ||||
  ++-++++- Select 8 KB PRG ROM at $8000


PRG Select 1 ($8010, $8008)

7  bit  0
---------
..PP PPPP
  || ||||
  ++-++++- Select 8 KB PRG ROM at $A000

PRG Select 2 ($9000)

7  bit  0
---------
..PP PPPP
  || ||||
  ++-++++- Select 8 KB PRG ROM at $C000

CHR Select 0…7 ($A000…$DFFF)

Write to CPU address 1KB CHR bank affected
$A000 $0000-$03FF
$A008 or $A010 $0400-$07FF
$B000 $0800-$0BFF
$B008 or $B010 $0C00-$0FFF
$C000 $1000-$13FF
$C008 or $C010 $1400-$17FF
$D000 $1800-$1BFF
$D008 or $D010 $1C00-$1FFF

Mirroring Control ($E000)

7  bit  0
---------
RS.. ..MM
||     ||
||     ++- Mirroring (0: vertical; 1: horizontal;
||                        2: one-screen, lower bank; 3: one-screen, upper bank)
|+-------- Silence expansion sound if set
+--------- WRAM enable (1: enable WRAM, 0: protect)

IRQ Control ($E008 - $F010)

$E008, $E010:  IRQ Latch
       $F000:  IRQ Control
$F008, $F010:  IRQ Acknowledge

Many VRC mappers use the same IRQ system. For details on IRQ operation, see VRC IRQs.

Sound ($9010, $9030)

For details on sound information, see VRC7 audio.

See also

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