Outer Banks 2x4 !!TOP!!

In OneBus mode, VT02+ consoles combine the Famicom cartridge connector's CPU and PPU address lines into one 32 MiB address space, with separate CPU and PPU bankswitch registers pointing to appropriately-placed code and picture data. The bankswitching scheme is based on, and indeed backwards-compatible to, the Nintendo MMC3's. The PPU address range reserved for CHR pattern data ($0000-$1FFF) is divided into 2x2 KiB and 4x1 KiB banks (2x4 KiB and 4x2 KiB in 4bpp modes), with the bank numbers always specified with 1 KiB granularity (2 KiB granularity in 4bpp modes). The final bank number is made up of five components:

Outer Banks 2x4

The Intermediate CHR Bank is only used if Background or Sprite Address Extension is not active while the respective pattern data are fetched, or neither is active while data is read or written via $2007. It provides three bits that go between the Middle and Outer CHR Bank number. A single Intermediate Bank number applies to all six CHR banks.

The Outer Bank number is used mostly by multicarts, but also by semi-large games for which the maximum Inner Bank size of 256 KiB is insufficient. A single Outer CHR Bank number applies to all six CHR banks. 041b061a72