CPROM: Difference between revisions
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[[Category:Discrete_logic_mappers]] | |||
NES-[[CPROM]] (and [[Famicom|HVC]]-CPROM) is a particular Nintendo cartridge board which uses discrete logic to provide up to four 4 KB banks of CHR RAM. | NES-[[CPROM]] (and [[Famicom|HVC]]-CPROM) is a particular Nintendo cartridge board which uses discrete logic to provide up to four 4 KB banks of CHR RAM. | ||
The [[iNES]] format assigns [[iNES Mapper 013|mapper 13]] to this board. | The [[iNES]] format assigns [[iNES Mapper 013|mapper 13]] to this board. | ||
Revision as of 09:26, 13 June 2009
NES-CPROM (and HVC-CPROM) is a particular Nintendo cartridge board which uses discrete logic to provide up to four 4 KB banks of CHR RAM. The iNES format assigns mapper 13 to this board.
Overview
- PRG ROM size: 32 KB (DIP-28 standard pinout)
- PRG ROM bank size: Not bankswitched
- PRG RAM: None
- CHR capacity: 16 KB RAM
- CHR bank size: 4 KB
- Nametable mirroring: Solder pads select vertical or horizontal mirroring
- Subject to bus conflicts: Yes
Banks
- PPU $0000-$0FFF: 4 KB fixed CHR RAM bank (first page)
- PPU $1000-$1FFF: 4 KB swappable CHR RAM page
Registers
Bank select ($8000-$FFFF)
7 bit 0
---- ----
xxxx xxCC
||
++- Select 4 KB CHR RAM bank for PPU $1000-$1FFF
Hardware
The CPROM board uses a 74HC161 (4-bit latch), 74HC04 (hex inverter), and 74HC08 (quad 2-input AND gate).
