VRC7

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VRC7
Company Konami
Games 2 in NesCartDB
Complexity ASIC
Boards 352402, 353429
PRG ROM capacity 512K
PRG ROM window 8K
PRG RAM capacity 8K
PRG RAM window 8K
CHR capacity 256K
CHR window 1K
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

See VRC7 pinout for chip pinout.

Banks

  • CPU $8000-$9FFF: 8 KB switchable PRG ROM bank
  • CPU $A000-$BFFF: 8 KB switchable PRG ROM bank
  • CPU $C000-$DFFF: 8 KB switchable PRG ROM bank
  • CPU $E000-$FFFF: 8 KB PRG ROM bank, fixed to the last bank
  • CHR $0000-$03FF: 1 KB switchable CHR ROM bank
  • CHR $0400-$07FF: 1 KB switchable CHR ROM bank
  • CHR $0800-$0BFF: 1 KB switchable CHR ROM bank
  • CHR $0C00-$0FFF: 1 KB switchable CHR ROM bank
  • CHR $1000-$13FF: 1 KB switchable CHR ROM bank
  • CHR $1400-$17FF: 1 KB switchable CHR ROM bank
  • CHR $1800-$1BFF: 1 KB switchable CHR ROM bank
  • CHR $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:

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

Although A5 is wired for sound registers on both ($x030, $x028), in the latter 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