VRC7

The Konami VRC7 is an ASIC mapper.

Overview

Manufacturer: Konami
PRG ROM size: Up to 512 KB
PRG ROM bank size: 8 KB at $8000, $A000, and $C000
PRG RAM: Up to 8 KB
CHR capacity: Up to 256 KB (only two games released: one has 128 KB ROM, the other has 8 KB RAM)
CHR bank size: 1 KB - swappable even when RAM instead of ROM
Nametable mirroring: Controlled by mapper
Subject to bus conflicts: No

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 ($A000)

7  bit  0
---------
CCCC CCCC
|||| ||||
++++-++++- Select 1 KB CHR ROM/RAM at PPU $0000

CHR Select 1 ($A010, $A008)

7  bit  0
---------
CCCC CCCC
|||| ||||
++++-++++- Select 1 KB CHR ROM/RAM at PPU $0400

CHR Select 2 ($B000)

7  bit  0
---------
CCCC CCCC
|||| ||||
++++-++++- Select 1 KB CHR ROM/RAM at PPU $0800

CHR Select 3 ($B010, $B008)

7  bit  0
---------
CCCC CCCC
|||| ||||
++++-++++- Select 1 KB CHR ROM/RAM at PPU $0C00

CHR Select 4 ($C000)

7  bit  0
---------
CCCC CCCC
|||| ||||
++++-++++- Select 1 KB CHR ROM/RAM at PPU $1000

CHR Select 5 ($C010, $C008)

7  bit  0
---------
CCCC CCCC
|||| ||||
++++-++++- Select 1 KB CHR ROM/RAM at PPU $1400

CHR Select 6 ($D000)

7  bit  0
---------
CCCC CCCC
|||| ||||
++++-++++- Select 1 KB CHR ROM/RAM at PPU $1800

CHR Select 7 ($D010, $D008)

7  bit  0
---------
CCCC CCCC
|||| ||||
++++-++++- Select 1 KB CHR ROM/RAM at PPU $1C00

Mirroring Control ($E000)

7  bit  0
---------
.... ..MM
       ||
       ++- Mirroring (0: vertical; 1: horizontal;
                          2: one-screen, lower bank; 3: one-screen, upper bank)

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.