VRC7

VRC7

Company	Konami
Complexity	ASIC
Boards	VRC7
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, 1, switchable
Bus conflicts	No
IRQ	Yes
Audio	Yes
iNES mappers	085

The Konami VRC7 is an ASIC mapper. In the iNES format, it's #85.

Registers

One wiring variant of the VRC7 uses A4 for registers ($x010), the other uses A3 ($x008). Although A5 is wired for sound registers on both ($x030, $x028), in the latter board the ceramic resonator believed 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

Konami VRC-VII Chip Info by Kevin Horton.