CPROM: Difference between revisions

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[[Category:Discrete_logic_mappers]]
[[Category:Discrete_logic_mappers]][[Category:in NesCartDB]][[Category:Nintendo licensed mappers]]
NES-[[CPROM]] (no [[Famicom|HVC]]-CPROM known) is a particular Nintendo cartridge board which uses discrete logic to provide up to four 4 KB banks of CHR RAM.
NES-[[CPROM]] (no [[Famicom|HVC]]-CPROM known) 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 '''mapper 13''' to this board.
Only ''[[wikipedia:Videomation|Videomation]]'', a paint program for NES, is known to use it.
Only ''[[wikipedia:Videomation|Videomation]]'', a paint program for NES, is known to use it.


== Overview ==
== Overview ==
* PRG ROM size: 32 KB (DIP-28 standard pinout)
* PRG ROM size: 32 KiB (DIP-28 standard pinout)
* PRG ROM bank size: Not bankswitched
* PRG ROM bank size: Not bankswitched
* PRG RAM: None
* PRG RAM: None
* CHR capacity: 16 KB RAM [[Category:Mappers with CHR RAM]]
* CHR capacity: 16 KiB RAM [[Category:Mappers with CHR RAM]] (in two [[6264 static RAM|8KiB RAMs]])
* CHR bank size: 4 KB
* CHR bank size: 4 KiB
* Nametable [[mirroring]]: Vertical
* Nametable [[mirroring]]: Vertical
* Subject to [[bus conflict]]s: Yes [[Category:Mappers with bus conflicts]]
* Subject to [[bus conflict]]s: Yes [[Category:Mappers with bus conflicts]]


== Banks ==
== Banks ==
* PPU $0000-$0FFF: 4 KB fixed CHR RAM bank (first page)
* PPU $0000-$0FFF: 4 KiB fixed CHR RAM bank (first page)
* PPU $1000-$1FFF: 4 KB swappable CHR RAM page
* PPU $1000-$1FFF: 4 KiB swappable CHR RAM page


== Registers ==
== Registers ==
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  xxxx xxCC
  xxxx xxCC
         ||
         ||
         ++- Select 4 KB CHR RAM bank for PPU $1000-$1FFF
         ++- Select 4 KiB CHR RAM bank for PPU $1000-$1FFF


== Hardware ==
== Hardware ==
The CPROM board uses a [[74161|74HC161]] (4-bit latch), [[7404|74HC04]] (hex inverter), and [[7408|74HC08]] (quad 2-input AND gate).
The CPROM board uses a [[74161|74HC161]] (4-bit latch) and a [[7408|74HC08]] (quad 2-input AND gate), with a [[7404|74HC04]] (hex inverter) to unify the two RAMs.
 
== See also ==
* [http://kevtris.org/mappers/nes_discrete/NES_CPROM.html Kevtris's notes]
* The [[NROM-368]] proposal is also compatible with this board.

Latest revision as of 22:25, 9 June 2016

NES-CPROM (no HVC-CPROM known) 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. Only Videomation, a paint program for NES, is known to use it.

Overview

  • PRG ROM size: 32 KiB (DIP-28 standard pinout)
  • PRG ROM bank size: Not bankswitched
  • PRG RAM: None
  • CHR capacity: 16 KiB RAM (in two 8KiB RAMs)
  • CHR bank size: 4 KiB
  • Nametable mirroring: Vertical
  • Subject to bus conflicts: Yes

Banks

  • PPU $0000-$0FFF: 4 KiB fixed CHR RAM bank (first page)
  • PPU $1000-$1FFF: 4 KiB swappable CHR RAM page

Registers

Bank select ($8000-$FFFF)

7  bit  0
---- ----
xxxx xxCC
       ||
       ++- Select 4 KiB CHR RAM bank for PPU $1000-$1FFF

Hardware

The CPROM board uses a 74HC161 (4-bit latch) and a 74HC08 (quad 2-input AND gate), with a 74HC04 (hex inverter) to unify the two RAMs.

See also