CPROM: Difference between revisions
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== Overview == | == Overview == | ||
* PRG ROM size: 32 | * 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 | * CHR capacity: 16 KiB RAM [[Category:Mappers with CHR RAM]] (in two [[6264 static ram|8KiB RAMs]]) | ||
* CHR bank size: 4 | * 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 | * PPU $0000-$0FFF: 4 KiB fixed CHR RAM bank (first page) | ||
* PPU $1000-$1FFF: 4 | * PPU $1000-$1FFF: 4 KiB swappable CHR RAM page | ||
== Registers == | == Registers == | ||
| Line 23: | Line 23: | ||
xxxx xxCC | xxxx xxCC | ||
|| | || | ||
++- Select 4 | ++- Select 4 KiB CHR RAM bank for PPU $1000-$1FFF | ||
== Hardware == | == Hardware == | ||
The CPROM board uses a [[74161|74HC161]] (4-bit latch) | 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. | ||
== Disch's Notes == | == Disch's Notes == | ||
| Line 66: | Line 66: | ||
| { 0 } | $8000 | | | { 0 } | $8000 | | ||
+-------------------------------+-------------------------------+ | +-------------------------------+-------------------------------+ | ||
== See also == | |||
* [http://kevtris.org/mappers/nes_discrete/NES_CPROM.html Kevtris's notes] | |||
Revision as of 04:36, 18 March 2013
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.
Disch's Notes
Here are Disch's original notes:
========================
= Mapper 013 =
========================
aka:
--------------------------
CPROM
Example Game:
--------------------------
Videomation
Notes:
--------------------------
This mapper uses 16k of CHR-RAM. CHR-RAM is swappable.
It also has bus conflicts!
Registers (**BUS CONFLICTS**):
--------------------------
$8000-FFFF: [.... ..CC]
C = Select 4k CHR (RAM) page @ $1000-1FFF
CHR Setup:
--------------------------
$0000 $0400 $0800 $0C00 $1000 $1400 $1800 $1C00
+-------------------------------+-------------------------------+
| { 0 } | $8000 |
+-------------------------------+-------------------------------+
