INES Mapper 180: Difference between revisions

From NESdev Wiki
Jump to navigationJump to search
(→‎Bank select ($8000-$FFFF): split disch's notes into its own section. Has bus conflicts. Mention lack of power-on guarantee)
(A few fixes)
Line 1: Line 1:
[[Category:iNES Mappers|180]][[Category:Discrete logic mappers|180]][[Category:in NesCartDB|180]]
[[Category:iNES Mappers|180]][[Category:Discrete logic mappers|180]][[Category:in NesCartDB|180]]


[[INES Mapper 180]] is used to represent a reconfiguration of the [[UxROM|UNROM]] board used only for the game ''Crazy Climber''. It is similar in principle to the more common UxROM configuration but uses AND logic ([[7408|74HC08]]) instead of OR logic ([[7432|74HC32]]), producing a fixed first bank at $8000 rather than a fixed last bank at $C000.
[[INES Mapper 180]] is used to represent a reconfiguration of the [[UxROM|UNROM]] board used only for the game ''Crazy Climber''. It is similar in principle to the more common [[INES Mapper 002]] configuration but uses AND logic ([[7408|74HC08]]) instead of OR logic ([[7432|74HC32]]), producing a fixed first bank at $8000 rather than a fixed last bank at $C000.


Because [[APU DMC]] is usually restricted to $C000-$FFFF, this behavior might be useful for games with a lot of recorded speech.
Because [[APU DMC]] is usually restricted to $C000-$FFFF, this behavior might be useful for games with a lot of recorded speech.
Line 29: Line 29:
       +++-- Select 16 KB PRG ROM bank for CPU $C000-$FFFF
       +++-- Select 16 KB PRG ROM bank for CPU $C000-$FFFF


== Disch's notes ==
== See also ==
  ========================
* [[UxROM]]
  =  Mapper 180          =
* [[Programming UNROM]]
  ========================
* NES mapper list by Dish [http://www.romhacking.net/documents/362/]
 
  Example Game:
  --------------------------
  Crazy Climber (J)
 
 
  Notes:
  ---------------------------
  This game uses a special input device (the crazy climber controller), so you'll need to emulate that in order
  to really test this mapper.
 
 
  Registers: (*** BUS CONFLICTS ***)
  --------------------------
 
    $8000-FFFF:  [.... .PPP]
      PRG Reg (16k @ $C000)
 
 
  PRG Setup:
  --------------------------
 
        $8000  $A000  $C000  $E000 
      +---------------+---------------+
      |    { 0 }    |    $8000    |
      +---------------+---------------+
 
 
  Powerup:
  --------------------------
  The register will probably contain 0 on cold powerup, but this is not guaranteed. The contents will be unchanged on reboot.

Revision as of 14:13, 21 April 2015


INES Mapper 180 is used to represent a reconfiguration of the UNROM board used only for the game Crazy Climber. It is similar in principle to the more common INES Mapper 002 configuration but uses AND logic (74HC08) instead of OR logic (74HC32), producing a fixed first bank at $8000 rather than a fixed last bank at $C000.

Because APU DMC is usually restricted to $C000-$FFFF, this behavior might be useful for games with a lot of recorded speech. But like BNROM and AxROM, this configuration requires the 6502's vectors to sit in the last few bytes of each bank.

Mapper 97 adds mapper-selectable 1sc/H/V mirroring (and changes the fixed bank).

Overview

  • PRG ROM size: 128 KB
  • PRG ROM bank size: 16 KB
  • PRG RAM: None
  • CHR capacity: 8 KB RAM
  • CHR bank size: Not bankswitched
  • Nametable mirroring: Solder pads select vertical or horizontal mirroring
  • Subject to bus conflicts: Yes

Banks

  • CPU $8000-$BFFF: 16 KB PRG ROM bank, fixed to the first bank
  • CPU $C000-$FFFF: 16 KB switchable PRG ROM bank

Registers

Bank select ($8000-$FFFF)

7  bit  0
---- ----
xxxx xPPP
      |||
      +++-- Select 16 KB PRG ROM bank for CPU $C000-$FFFF

See also

Retrieved from "https://www.nesdev.org/w/index.php?title=INES_Mapper_180&oldid=5385"