Difference between revisions of "NES 2.0 submappers"

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m (068: Sunsoft 4: "different PRG behavior" appears to be an understatement, this is a lock-on cartridge)
(It turns out that ''Dream Master'' uses the N175, not the N340.)
 
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Most emulators using [[iNES]] format distinguish these using CRC, SHA-1, or other hashes of the PRG ROM and CHR ROM, but this works only for games published prior to 1997, not for fan translations or ROM hacks, and not for new games on the same mapper.
 
Most emulators using [[iNES]] format distinguish these using CRC, SHA-1, or other hashes of the PRG ROM and CHR ROM, but this works only for games published prior to 1997, not for fan translations or ROM hacks, and not for new games on the same mapper.
  
Submapper 0 represents the default iNES behavour, so that backward compatibility is maintained.
+
Submapper 0 represents the default iNES behavour, so that backward compatibility is maintained with existing ROMs.
  
'''This document is a living specification. Proposals for new submappers should be made at:''' [[NES 2.0 submappers\Proposals|Proposals]].
+
Submapper allocations that are listed as "deprecated" were assigned by kevtris' original proposal, but have no known use cases. The deprecation reserves these unused allocations to maintain continuity and compatibility.
 +
 
 +
'''This document is a living specification. Proposals for new submappers should be made at:''' [[NES 2.0 submappers/Proposals|Proposals]].
  
 
== [[iNES Mapper 001|001]]: [[MMC1]] ==
 
== [[iNES Mapper 001|001]]: [[MMC1]] ==
Most [[SxROM|MMC1 boards]] wire all PRG ROM address lines A14-A18 to the mapper's output in a fairly predictable manner.
+
Most [[SxROM|MMC1 boards]] are compatible with the standard mapper 1 behavior (submapper [[#001: 0|0]]).
  
Boards with CHR RAM wire PRG ROM A18 and the PRG RAM address lines to otherwise unused CHR bank outputs.
+
Boards with CHR-RAM usually reuse the CHR banking lines to address other things.
 +
* SUROM, SOROM, and SXROM implement extra PRG-ROM and PRG-RAM banking (''deprecated'' submappers [[#001: 1, 2, 4 = SUROM, SOROM, SXROM|1, 2, 4]]).
 +
* SNROM implements a redundant PRG-RAM enable (no assigned submapper).
  
Boards designed to take a 32 KiB PRG ROM, either connect PRG ROM A14 to the MMC1's output (SIROM), or directly to CPU A14 (SEROM, SHROM, SH1ROM).
+
The variant MMC1A chip was assigned to [[iNES Mapper 155|mapper 155]] (''deprecated'' submapper [[#001: 3|3]]).
  
Submappers 1, 2 and 4 have register configurations that necessitate specific PRG ROM and PRG RAM sizes. These can alternatively be detected by the relevant size fields in the header.
+
Most boards with 32k of PRG-ROM have no PRG banking: SEROM, SHROM, SH1ROM (submapper [[#001: 5 Fixed PRG|5]]).
  
 
=== 001: 0 ===
 
=== 001: 0 ===
 
Normal behavior.
 
Normal behavior.
  
=== 001: 1 ===
+
=== 001: 1, 2, 4 = SUROM, SOROM, SXROM ===
[[SUROM]] reuses a CHR banking line as PRG RAM enable.
+
'''Deprecated.'''
  
Can alternatively be identified by the following conditions:
+
These submappers are a redundancy. The difference between these boards and the "normal" MMC1 implementation is exclusively dependent on the sizes of CHR, PRG RAM, and PRG ROM. Because of this, the addition of PRG RAM to the NES 2.0 specification was enough to make these compatible with submapper 0.
* PRG ROM = 256k or 128k
+
* PRG RAM = 8k
+
* CHR RAM = 8k
+
  
Games:
+
These three boards used 8k CHR RAM, and reused the CHR banking bits to bank PRG ROM and RAM instead. The specific boards can be detected by these sizes, or simply emulated together in submapper 0:
* ''Dragon Warrior III''
+
* ''Dragon Warrior IV'' / ''Dragon Quest IV''
+
* ''Ninjara Hoi!''
+
  
=== 001: 2 ===
+
$A000 and $C000:
[[SOROM]] reuses CHR banking lines as PRG RAM banking and enable.
+
4bit0
 
+
-----
Can alternatively be identified by the following conditions:
+
EDCBA
* PRG ROM = 256k or 128k
+
|||||
* PRG RAM = 16k
+
||||+- CHR A12
* CHR RAM = 8k
+
|||+-- CHR A13, if extant (CHR >= 16k)
 
+
||+--- CHR A14, if extant; and PRG RAM A14, if extant (PRG RAM = 32k, submapper 4)
Games:
+
|+---- CHR A15, if extant; and PRG RAM A13, if extant (PRG RAM >= 16k, submappers 2, 4)
* ''Genghis Khan'' / ''Aoki Ookami to Shiroki Mejika: Genghis Khan''
+
+----- CHR A16, if extant; and PRG ROM A18, if extant (PRG ROM = 512k, submappers 1, 4)
* ''Nobunaga's Ambition'' / ''Nobunaga no Yabou: Zenkokuban''
+
* ''Romance of the Three Kingdoms''
+
* ''Sangokushi''
+
 
+
=== 001: 3 ===
+
'''Deprecated.''' Use [[iNES Mapper 155]] instead.
+
  
=== 001: 4 ===
+
The following games are on SUROM (submapper 1):
[[SXROM]] reuses CHR banking lines as PRG ROM banking and PRG RAM enable.
+
* ''[http://bootgod.dyndns.org:7777/profile.php?id=1273 Dragon Warrior III]''
 +
* ''[http://bootgod.dyndns.org:7777/profile.php?id=1276 Dragon Warrior IV]'' / ''[http://bootgod.dyndns.org:7777/profile.php?id=1526 Dragon Quest IV]''
 +
* ''[http://bootgod.dyndns.org:7777/profile.php?id=1531 Ninjara Hoi!]''
  
Can alternatively be identified by the following conditions:
+
SOROM (submapper 2):
* PRG ROM = 512k
+
* ''[http://bootgod.dyndns.org:7777/profile.php?id=919 Genghis Khan]'' / ''[http://bootgod.dyndns.org:7777/profile.php?id=1528 Aoki Ookami to Shiroki Mejika: Genghis Khan]''
* PRG RAM = 8k
+
* ''[http://bootgod.dyndns.org:7777/profile.php?id=497 Nobunaga's Ambition]'' / ''[http://bootgod.dyndns.org:7777/profile.php?id=1529 Nobunaga no Yabou: Zenkokuban]''
* CHR RAM = 8k
+
* ''[http://bootgod.dyndns.org:7777/profile.php?id=730 Romance of the Three Kingdoms]'' / ''[http://bootgod.dyndns.org:7777/profile.php?id=3170 Sangokushi]''
  
Games:
+
SXROM (submapper 4):
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=3642 Final Fantasy I & II]''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=3642 Final Fantasy I & II]''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=3757 The Best Play Pro Yakyuu Special]''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=3757 The Best Play Pro Yakyuu Special]''
 
* ''[http://forums.nesdev.com/viewtopic.php?f=22&t=7231 PR8]''. If extra RAM is missing, it gives a [http://forums.nesdev.com/viewtopic.php?f=2&t=7629 "DOES NOT WORK IN THIS EMULATOR" error].
 
* ''[http://forums.nesdev.com/viewtopic.php?f=22&t=7231 PR8]''. If extra RAM is missing, it gives a [http://forums.nesdev.com/viewtopic.php?f=2&t=7629 "DOES NOT WORK IN THIS EMULATOR" error].
  
=== 001: 5 ===
+
If any NES 2.0 ROMs are found using these deprecated submappers, the CHR, PRG RAM, and PRG ROM sizes must appropriately match to be a valid header.
 +
 
 +
=== 001: 3 ===
 +
'''Deprecated.'''
 +
 
 +
This originally described a submapper that was already implemented as [[iNES Mapper 155]].
 +
 
 +
=== 001: 5 Fixed PRG ===
 +
 
 
[[SEROM]], [[SHROM]], [[SH1ROM]] use a fixed 32k PRG ROM with no banking support. (This is distinct from [[SIROM]] which has 32k of bankable PRG ROM.)
 
[[SEROM]], [[SHROM]], [[SH1ROM]] use a fixed 32k PRG ROM with no banking support. (This is distinct from [[SIROM]] which has 32k of bankable PRG ROM.)
  
 
PRG ROM A14 is connected directly to CPU A14 (and MMC1 A14 input) instead of MMC1 A14 output.
 
PRG ROM A14 is connected directly to CPU A14 (and MMC1 A14 input) instead of MMC1 A14 output.
  
* ''Adventures of Lolo''
+
Existing games are compatible with submapper 0 if $8000-BFFF is initialized to the low bank, and $C000-FFFF is initialized to the high bank. These boards were used in several games: [http://bootgod.dyndns.org:7777/search.php?keywords=serom&kwtype=pcb SEROM] [http://bootgod.dyndns.org:7777/search.php?keywords=shrom&kwtype=pcb SHROM] [http://bootgod.dyndns.org:7777/search.php?keywords=sh1rom&kwtype=pcb SH1ROM]
* ''Airwolf''
+
 
* ''The All New Family Feud''
+
Test ROM:
* ''Anticipation''
+
* ''[http://forums.nesdev.com/download/file.php?id=3753 serom.zip]'' - validates non-existence of PRG banking control. ([http://forums.nesdev.com/viewtopic.php?p=153298#p153298 forum post])
* ''Boulder Dash''
+
 
* ''Dr. Mario''
+
== [[iNES Mapper 002|002]], [[iNES Mapper 003|003]], [[iNES Mapper 007|007]]: [[UxROM]], [[CNROM]], [[AxROM]] ==
* ''Hirake! Ponkikki''
+
 
* ''Palamedes''
+
Mappers 2, 3, and 7 describe [[:Category:Discrete logic mappers|discrete logic mappers]] that are usually subject to [[Bus conflict|bus conflicts]]. Most of these games are programmed in a way that does not rely on the bus conflict behaviour, but software bugs may expose the difference (e.g. ''Cybernoid''<ref>[http://forums.nesdev.com/viewtopic.php?t=7273 NESDev post] explaining Cybernoid's bugs.</ref>). Because these differences are obscure, the default iNES implementation for mappers 2 and 3 has been inconsistent across emulators, some with bus conflicts, some without. Mapper 7 is normally emulated without bus conflicts, because of a small number of games using the [[ANROM]] board which rely on this.
* ''Palamedes II: Star Twinkles''
+
 
* ''R.C. Pro-Am''
+
Two submappers allow this ambiguity to be resolved, by selecting a specific behaviour:
* ''Sesame Street 123''
+
 
* ''Sesame Street ABC''
+
0: Default iNES behaviour (Emulators should warn the user and/or enforce bus conflicts for mappers 2 and 3, and should warn the user and/or fail to enforce bus conflicts for mapper 7)<br>
* ''Sky Kid''
+
1: Bus conflicts do not occur<br>
* ''Snake Rattle 'n Roll''
+
2: Bus conflicts occur, producing the bitwise AND of the written value and the value in ROM
* ''Taboo: The Sixth Sense''
+
 
* ''Tetris''
+
Although all Nintendo-manufactured games using normal CNROM (mapper 3), normal UxROM (mapper 2), and inverted UxROM (mapper 180) had bus conflicts, apparently several unlicensed games require their absence, as does the updated version of ''Donkey Kong'' with the pie factory level<ref>[http://www.nintendoage.com/forum/messageview.cfm?catid=22&threadid=44613 Nintendoage thread] discussing Donkey Kong Pie Factory.</ref>.
 +
 
 +
AxROM (mapper 7) is the only known licensed discrete logic mapper to unreliably come with [[bus conflict]] prevention circuitry. While no game documented in NesCartDB was released in one region on multiple board variants, several games did change boards when localized.
 +
 
 +
New ROMs are encouraged to specify submapper 2 to verify correct behaviour with bus conflicts.
 +
 
 +
CNROM with security diodes (mapper 185) has a different set of submapper definitions.
 +
 
 +
=== 002: 0, 1, 2 [[UxROM]] ===
 +
Test ROMs: ([//forums.nesdev.com/viewtopic.php?p=157804#p157804 forum post])
 +
* ''2_test_0.nes'' - Unspecified.
 +
* ''2_test_1.nes'' - No bus conflicts.
 +
* ''2_test_2.nes'' - AND bus conflicts.
 +
 
 +
=== 003: 0, 1, 2 [[CNROM]] ===
 +
Test ROMs: ([//forums.nesdev.com/viewtopic.php?p=154555#p154555 forum post])
 +
* ''3_test_0.nes'' - Unspecified.
 +
* ''3_test_1.nes'' - No bus conflicts.
 +
* ''3_test_2.nes'' - AND bus conflicts.
  
Some of these games may be compatible with submapper 0 if $8000-BFFF is initialized to the low bank, and $C000-FFFF is initialized to the high bank, and the game never changes this. However, if an NES 2.0 header is specified, it should be presumed that a specific submapper is desired.
+
=== 007: 0, 1, 2 [[AxROM]] ===
 +
Test ROMs: ([//forums.nesdev.com/viewtopic.php?p=157804#p157804 forum post])
 +
* ''7_test_0.nes'' - Unspecified.
 +
* ''7_test_1.nes'' - No bus conflicts.
 +
* ''7_test_2.nes'' - AND bus conflicts.
  
 
== [[iNES Mapper 004|004]]: [[MMC3]] ==
 
== [[iNES Mapper 004|004]]: [[MMC3]] ==
Line 89: Line 113:
  
 
There are three known kinds of IRQ:
 
There are three known kinds of IRQ:
# MMC3A: IRQ is asserted on A12 rise, and loading the latch with 0 disables IRQ. Some chips labeled MMC3B also have this "old style" behavior. No games are known to rely on this behavior.
+
# MMC3A: IRQ is asserted on A12 rise, and loading the latch with 0 disables IRQ. Some chips labeled MMC3B also have this "old style" behavior. At least one unlicensed game relies on this behavior.
 
# MMC3C: IRQ is asserted on A12 rise, and loading the latch with 0 produces an IRQ on every scanline. Some chips labeled MMC3B also have this "new style" behavior, as does the MMC6. Some later games rely on this behavior.
 
# MMC3C: IRQ is asserted on A12 rise, and loading the latch with 0 produces an IRQ on every scanline. Some chips labeled MMC3B also have this "new style" behavior, as does the MMC6. Some later games rely on this behavior.
 
# MC-ACC: IRQ is asserted on A12 fall, typically four pixels later than MMC3C. Interrupts can be produced every scanline, like the MMC3C.<ref>[http://forums.nesdev.com/viewtopic.php?p=128148#p128148 MC-ACC IRQ test results]</ref>
 
# MC-ACC: IRQ is asserted on A12 fall, typically four pixels later than MMC3C. Interrupts can be produced every scanline, like the MMC3C.<ref>[http://forums.nesdev.com/viewtopic.php?p=128148#p128148 MC-ACC IRQ test results]</ref>
Line 102: Line 126:
 
Normal. (MMC3C)
 
Normal. (MMC3C)
  
=== 004: 1 ===
+
=== 004: 1 MMC6 ===
 
[[MMC6]] has an alternative PRG-RAM enable and write protection scheme designed for its internal 1k PRG RAM.
 
[[MMC6]] has an alternative PRG-RAM enable and write protection scheme designed for its internal 1k PRG RAM.
 
* ''StarTropics''
 
* ''StarTropics''
Line 108: Line 132:
  
 
=== 004: 2 ===
 
=== 004: 2 ===
MMC3C with hard wired mirroring.
+
'''Deprecated.'''
* ''(no known games)''
+
 
 +
This originally described MMC3C with hard wired mirroring. No games are known to require this.
  
=== 004: 3 ===
+
=== 004: 3 MC-ACC ===
 
MC-ACC  
 
MC-ACC  
  
Line 128: Line 153:
 
* ''WWF King of the Ring''
 
* ''WWF King of the Ring''
 
* ''WWF WrestleMania: Steel Cage Challenge''
 
* ''WWF WrestleMania: Steel Cage Challenge''
 +
 +
=== 004: 4 MMC3A ===
 +
Loading the latch with 0 disables IRQ.
 +
* SuperGame's ''Aladdin'' (Mapper 4 version)
 +
== [[iNES Mapper 016|016]]: Bandai FCG board ==
 +
{{:INES Mapper 016/Submapper table}}
 +
== [[iNES Mapper 019|019]]: Namco 129/163 ==
 +
The NES 2.0 submapper is used to specify the mixing resistor that determines the relative volume of the expansion audio channels against the APU's audio channels:
 +
{{:INES Mapper 019/Submapper table}}
 +
== [[iNES Mapper 021|021]], [[iNES Mapper 023|023]], [[iNES Mapper 025|025]]: [[VRC2]] / [[VRC4]] ==
 +
 +
These three mappers collect various configurations of [[VRC2]] and [[VRC4]] boards.
 +
 +
VRC2 is mostly a subset of VRC4, with differences including:
 +
* VRC2 has a serial EEPROM interface which no Konami game ever connected an actual EEPROM to, but one PCB is wired so that it functions as a single bit of memory mapped at $6000-6FFF<ref>http://forums.nesdev.com/viewtopic.php?t=8274 VRC2 memory bit at $6000-$6FFF</ref>
 +
* VRC4 supports horizontal, vertical and one-screen nametable mirroring while VRC2 supports only horizontal and vertical mirroring<ref>http://forums.nesdev.com/viewtopic.php?t=13473 VRC2 mirroring selection tested on hardware</ref>
 +
* VRC4 supports two PRG ROM banking modes, similar to MMC3's. VRC2 only has one PRG ROM banking mode.
 +
* VRC4 has an interrupt device that VRC2 does not.
 +
 +
Additionally, different boards connect the address lines for the registers in various arrangements. The three iNES mappers 21, 23, and 25 each combine multiple boards whose addresses overlap. This is enough for game compatibility, but it creates an ugly combination that does not accurately describe the original hardware of either board.
 +
 +
=== Submapper assignment ===
 +
 +
Konami's [[VRC2 and VRC4]] mappers have several variations of how the board connects low CPU address lines among A7-A0 to the port select lines of the mapper.
 +
Mappers [[iNES Mapper 021|21]], [[iNES Mapper 021|23]] and [[iNES Mapper 021|25]] each combine two non-overlapping addressing variations, and neglect to specify VRC2 vs VRC4.
 +
 +
Mapper [[iNES Mapper 021|22]] is related, but only supports one variation (VRC2a) and has a different CHR banking arrangement than the others. It does not require submapper disambiguation.
 +
 +
There are three variations of the [[VRC2]] boards, and five of [[VRC4]]:
 +
 +
{| class="wikitable sortable"
 +
!colspan=7|VRC2
 +
|-
 +
! Nickname || PCB || A0 || A1 || Registers || iNES mapper || submapper
 +
|-
 +
| VRC2a || 351618 || A1 || A0 || $x000, $x002, $x001, $x003 || 22 || 0
 +
|-
 +
| VRC2b || many[[#VRC2bPCB|†]] || A0 || A1 || $x000, $x001, $x002, $x003 || 23 || 3
 +
|-
 +
| VRC2c || 351948 || A1 || A0 || $x000, $x002, $x001, $x003 || 25 || 3
 +
|}
 +
 +
{| class="wikitable sortable"
 +
!colspan=7|VRC4
 +
|-
 +
! Nickname || PCB || A0 || A1 || Registers || iNES mapper || submapper
 +
|-
 +
| VRC4a || 352398 || A1 || A2 || $x000, $x002, $x004, $x006 || 21 || 1
 +
|-
 +
| VRC4b || 351406 || A1 || A0 || $x000, $x002, $x001, $x003 || 25 || 1
 +
|-
 +
| VRC4c || 352889 || A6 || A7 || $x000, $x040, $x080, $x0C0 || 21 || 2
 +
|-
 +
| VRC4d || 352400 || A3 || A2 || $x000, $x008, $x004, $x00C || 25 || 2
 +
|-
 +
| VRC4e || 352396 || A2 || A3 || $x000, $x004, $x008, $x00C || 23 || 2
 +
|-
 +
| VRC4f || - || A0 || A1 || $x000, $x001, $x002, $x003 || 23 || 1
 +
|}
 +
 +
: † {{anchor|VRC2bPCB}} The VRC2b PCBs include: 350603, 350636, 350926, 351179
 +
 +
This submapper assigment uses the following symmetrical arrangement:
 +
* 0. Both addressing
 +
* 1. Lower addressing, VRC4
 +
* 2. Higher addressing, VRC4
 +
* 3. Lower addressing, VRC2 ''(no known examples for mapper 21)''
 +
* 4. ''Higher addressing, VRC2 (no known examples)''
 +
 +
=== 021 / 023 / 025: 0 ===
 +
The default implementation acts as a VRC4 (mostly compatible superset of VRC2), and responds to register writes in one or more configurations simultaneously (supporting both boards at once).
 +
 +
=== 021 / 023 / 025: 1, 2 VRC4 ===
 +
These allocations each request a single specific addressing scheme for VRC4, rather than the combined version used by submapper 0.
 +
 +
* 021: 1 VRC4a
 +
* 025: 1 VRC4b
 +
* 021: 2 VRC4c
 +
* 025: 2 VRC4d
 +
* 023: 2 VRC4e
 +
* 023: 1 VRC4f
 +
 +
=== 023: 1 VRC4f ===
 +
Some unlicensed games used a second-source VRC4 clone with register addressing identical to VRC2b (the simplest contiguous in-order interpretation: 0,1,2,3). This was used in ''World Hero''.
 +
 +
=== 023: 3 VRC2b ===
 +
Games on PCB 350926 (and its chip-on-board equivalents) rely on a single bit of RAM mapped in the region from $6000-$6FFF. Prior to NES 2.0, these games were supported by implementing WRAM in this region (despite this board not having WRAM). This board was used in ''[http://bootgod.dyndns.org:7777/profile.php?id=3986 Contra (J)]'', ''[http://bootgod.dyndns.org:7777/profile.php?id=1568 Ganbare Goemon 2]'' and ''[http://bootgod.dyndns.org:7777/profile.php?id=2274 Konami Wai Wai World]''.
 +
 +
There are other VRC2 boards with the same register addressing as 350926 but without this feature ($6000-$6FFF is effectively open bus on them), but no game relies on the ''lack'' of the single bit of memory, so a separate submapper has not been allocated for them. These boards were used in ''[http://bootgod.dyndns.org:7777/profile.php?id=3802 Dragon Scroll]'', ''[http://bootgod.dyndns.org:7777/profile.php?id=2276 Getsu Fuuma Den]'', and ''[http://bootgod.dyndns.org:7777/profile.php?id=2278 Jarinko Chie]''.
 +
 +
Since this submapper represents VRC2, it should not implement the VRC4-only one-screen mirroring, PRG ROM banking modes, or IRQ capabilities. Wai Wai World depends on the lack of one-screen mirroring; it will have corrupt backgrounds in the vertically-scrolling stages and the ending if emulated with VRC4 capabilities.
 +
 +
=== 025: 3 VRC2c ===
 +
''[http://bootgod.dyndns.org:7777/profile.php?id=3823 Ganbare Goemon Gaiden: Kieta Ougon Kiseru]'' uses the same register addressing as VRC4b, but is VRC2, so this submapper should not implement VRC4-only capabilities.
 +
 +
=== Test ROMs ===
 +
* [https://forums.nesdev.com/viewtopic.php?p=203716#p203716 VRC2/4 test program]
  
 
== [[iNES Mapper 032|032]]: Irem G101 ==
 
== [[iNES Mapper 032|032]]: Irem G101 ==
Line 135: Line 257:
 
Normal (H/V mapper-controlled mirroring)
 
Normal (H/V mapper-controlled mirroring)
  
=== 032: 1 ===
+
=== 032: 1 Major League ===
 
CIRAM A10 is tied high (fixed one-screen mirroring) and PRG banking style is fixed as 8+8+16F
 
CIRAM A10 is tied high (fixed one-screen mirroring) and PRG banking style is fixed as 8+8+16F
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=3800 Major League]''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=3800 Major League]''
Line 143: Line 265:
  
 
=== 034: 0 ===
 
=== 034: 0 ===
Normal. Both mappers can be implemented simultaneously without incompatibility.
+
Normal.
  
Because the NINA-001 supports CHR banking and BNROM does not, the presence of more than 8 KiB of CHR implies NINA-001, and could be used to select between two exclusive mapper implementations.
+
To disambiguate the two mappers, emulators have taken various approaches:
 +
* The presense of CHR larger than 8 KiB unambiguously requires NINA-001, as BNROM has no CHR banking.
 +
* The presence of CHR-RAM is taken to imply BNROM, because both extant BNROM games use CHR-RAM.
 +
* CRC tests may be used to select a mapper for previously known ROMs.
 +
* Implement both mappers simultaneously. This is compatible with existing games.
  
=== 034: 1 ===
+
Selecting a single implementation based on CHR results in greater accuracy, since no game was ever intended for the combined definition.
NINA-001 only.
+
 
* ''(no extant games require this)''
+
New programs should not attempt to use a combined BNROM + NINA-001 mapper because this is not reliably available across emulators. Unusual combinations like NINA-001 with CHR-RAM are theoretically possible, but unlikely to be emulated consistently.
 +
 
 +
=== 034: 1 NINA-001 ===
 +
[[NINA-001]] only.
 +
 
 +
Test ROM: ([//forums.nesdev.com/viewtopic.php?p=153334#p153334 forum post])
 +
* ''34_test_1.nes'' - NINA-001 with CHR ROM.
 +
 
 +
=== 034: 2 BNROM ===
 +
[[BNROM]] only.
 +
 
 +
Some unlicensed boards by Union Bond were a variation of BNROM that included PRG RAM. These may also use this submapper if PRG RAM is specified in the NES 2.0 header.
 +
 
 +
Test ROM: ([//forums.nesdev.com/viewtopic.php?p=153334#p153334 forum post])
 +
* ''34_test_2.nes'' - BNROM with CHR RAM.
  
 
== [[iNES Mapper 068|068]]: Sunsoft 4 ==
 
== [[iNES Mapper 068|068]]: Sunsoft 4 ==
Line 157: Line 297:
 
0: Normal (max 256KiB PRG)
 
0: Normal (max 256KiB PRG)
  
=== 068: 1 ===
+
=== 068: 1 Dual Cartridge System ===
 
1: Sunsoft Dual Cartridge System a.k.a. NTB-ROM (max 128KiB PRG, licensing IC present, external option ROM of up to 128KiB should be selectable by a second menu)
 
1: Sunsoft Dual Cartridge System a.k.a. NTB-ROM (max 128KiB PRG, licensing IC present, external option ROM of up to 128KiB should be selectable by a second menu)
 
* [http://bootgod.dyndns.org:7777/profile.php?id=2265 ''Nantettatte!! Baseball'']
 
* [http://bootgod.dyndns.org:7777/profile.php?id=2265 ''Nantettatte!! Baseball'']
Line 169: Line 309:
 
Hardwired horizontal or vertical mirroring.
 
Hardwired horizontal or vertical mirroring.
  
=== 071 : 1 ===
+
=== 071: 1 Fire Hawk ===
 
Mapper controlled single-screen mirroring.
 
Mapper controlled single-screen mirroring.
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=733 Fire Hawk]''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=733 Fire Hawk]''
Line 181: Line 321:
 
Unspecified.
 
Unspecified.
  
=== 078: 1 ===
+
=== 078: 1 Cosmo Carrier ===
 
Single-screen mirroring (nibble-swapped [[INES Mapper 152|mapper 152]]).
 
Single-screen mirroring (nibble-swapped [[INES Mapper 152|mapper 152]]).
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=3968 Uchuusen: Cosmo Carrier]''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=3968 Uchuusen: Cosmo Carrier]''
Line 188: Line 328:
 
'''Deprecated.'''
 
'''Deprecated.'''
  
=== 078: 3 ===
+
This described a variation with fixed vertical mirroring, and WRAM. There is no known use case.
 +
 
 +
=== 078: 3 Holy Diver ===
 
Mapper-controlled H/V mirroring.
 
Mapper-controlled H/V mirroring.
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=4038 Holy Diver]''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=4038 Holy Diver]''
 +
 +
==[[iNES Mapper 085|085]]: Konami VRC7 ==
 +
* VRC7b uses A3 to select registers ($x008), used in Tiny Toon Adventures (Submapper 1).
 +
* VRC7a uses A4 to select registers ($x010), used in Lagrange Point (Submapper 2).
 +
 +
== [[iNES Mapper 091|091]]: Super Fighter III ==
 +
*Submapper 0: YY830624C/JY830848C (J.Y. Company clone board)
 +
*Submapper 1: EJ-006-1 (original ''Super Fighter III'' board).
 +
 +
== [[iNES Mapper 114|114]]: Sugar Softec/Hosenkan, fixed MMC3 scrambling pattern ==
 +
Registers at $6000 (and $6001, although not used for effect by existing games)
 +
* Submapper 0: The Lion King, Aladdin
 +
* Submapper 1: Boogerman (different scrambling pattern)
 +
 +
== [[iNES Mapper 178|178]].1: Gameinis Infrared Sensor ==
 +
* Submapper 0: No infrared sensor present
 +
* Submapper 1: Gameinis Infrared Sensor present
 +
== [[iNES Mapper 185|185]]: CNROM used to selectively disable CHR-ROM ==
 +
A few NROM-like games were released on CNROM boards where all four bits of the latch were solely used as an anti-piracy measure. Games would check that CHR-ROM is disabled unless the latch holds the correct one of the four possible bank values. See this [http://forums.nesdev.com/viewtopic.php?f=3&t=16700 thread] for test ROMs and example implementation code.
 +
 +
=== 185: 0 ===
 +
Correct bank value unknown. A heuristic that works with all known games that use this mapper is to return $FF on the first two reads from CPU $2007 after a reset.
 +
 +
=== 185: 4 ===
 +
Enable CHR-ROM if bits 0..1 of the latch hold the value 0, otherwise disable CHR-ROM.
 +
 +
=== 185: 5 ===
 +
Enable CHR-ROM if bits 0..1 of the latch hold the value 1, otherwise disable CHR-ROM.
 +
 +
=== 185: 6 ===
 +
Enable CHR-ROM if bits 0..1 of the latch hold the value 2, otherwise disable CHR-ROM.
 +
 +
=== 185: 7 ===
 +
Enable CHR-ROM if bits 0..1 of the latch hold the value 3, otherwise disable CHR-ROM.
  
 
== [[iNES Mapper 210|210]]: Namco 175 and 340 ==
 
== [[iNES Mapper 210|210]]: Namco 175 and 340 ==
 
[[iNES Mapper 210|Mapper 210]] doesn't distinguish between the 175's hardwired mirroring and 340's 1/H/V mirroring.
 
[[iNES Mapper 210|Mapper 210]] doesn't distinguish between the 175's hardwired mirroring and 340's 1/H/V mirroring.
  
Also, previous confusion and compatibility code used by Namco when they were developing games means that many 175- and 340- using games are incorrectly tagged as [[iNES Mapper 19|mapper 19]].
+
Also, previous confusion and compatibility code used by Namco when they were developing games means that many 175- and 340- using games are incorrectly tagged as [[iNES Mapper 019|mapper 19]].
  
 
=== 210: 0 ===
 
=== 210: 0 ===
No advisory statement is made (use runtime heuristics)
+
No advisory statement is made (use runtime heuristics suggested at [[iNES Mapper 210|mapper 210]])
  
=== 210: 1 ===
+
=== 210: 1 N175 ===
 
Namco 175. Hardwired mirroring, no IRQ.
 
Namco 175. Hardwired mirroring, no IRQ.
* ''See [[iNES Mapper 210|mapper 210]] for a list of games.''
 
  
=== 210: 2 ===
+
* ''Dream Master''
 +
* ''Famista '91''
 +
* ''Family Circuit '91''
 +
* ''Chibi Maruko-chan: Uki Uki Shopping''
 +
* ''Heisei Tensai Bakabon / Genius Bakabon''
 +
 
 +
=== 210: 2 N340 ===
 
Namco 340. 1/H/V mirroring, no IRQ, no internal or external RAM.
 
Namco 340. 1/H/V mirroring, no IRQ, no internal or external RAM.
* ''See [[iNES Mapper 210|mapper 210]] for a list of games.''
+
 
 +
* ''Splatterhouse''
 +
* ''Wagyan Land 2''
 +
* ''Famista '92''
 +
* ''Top Striker''
 +
* ''Wagyan Land 3''
 +
* ''Famista '93''
 +
* ''Famista '94''
 +
 
 +
== [[iNES Mapper 215|215]]: Sugar Softec, selectable MMC3 scrambling pattern ==
 +
Registers at $5000-$5007.
 +
* Submapper 0: UNL-8237 (two non-overlapping outer bank bits for PRG/CHR each)
 +
* Submapper 1: UNL-8237A  (three overlapping outer bank bits for PRG/CHR each)
  
 
== [[iNES Mapper 232|232]]: Quattro ==
 
== [[iNES Mapper 232|232]]: Quattro ==
Line 213: Line 406:
 
The Aladdin Deck Enhancer version of these multicarts used a different banking scheme.
 
The Aladdin Deck Enhancer version of these multicarts used a different banking scheme.
  
=== 323: 0 ===
+
=== 232: 0 ===
 
0: Normal
 
0: Normal
  
=== 232: 1 ===
+
=== 232: 1 Aladdin Deck Enhancer ===
 
Aladdin Deck Enhancer variation. Swap the bits of the outer bank number.
 
Aladdin Deck Enhancer variation. Swap the bits of the outer bank number.
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=553 Quattro Adventure] (Aladdin Deck Enhancer)''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=553 Quattro Adventure] (Aladdin Deck Enhancer)''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=550 Quattro Sports] (Aladdin Deck Enhancer)''
 
* ''[http://bootgod.dyndns.org:7777/profile.php?id=550 Quattro Sports] (Aladdin Deck Enhancer)''
 +
* ''Pegasus 4-in-1''
 +
* ''Super Adventure Quests'' (European release of ''Quattro Adventure'')
 +
 +
== [[NES 2.0 Mapper 256]] ==
 +
Several plug-and-play consoles use a simple protection scheme intended to prevent interchanging the ROM data between different consoles. The protection scheme works by simply swapping the addresses of the bankswitch registers. Some patterns only change the VTxx-native register addresses, others apply to the MMC3 compatibility registers as well.
 +
 +
Other plug-and-play consoles, in particular those by Jungletac, scramble CPU opcode bytes (and only those) by swapping bits. These consoles power-on with opcode scrambling enabled, but allow it to be disabled --- for example, to run a pirated licensed NES game without modifying it --- by writing to a register.
 +
{{:NES 2.0 Mapper 256/Submapper table}}
 +
 +
== [[NES 2.0 Mapper 268|268]]: Coolboy/Mindkids ==
 +
*Submapper 0: Coolboy (outer bank registers at $6000-$6003)
 +
*Submapper 1: Mindkids (outer bank registers $5000-$5003)
  
 
== References ==
 
== References ==

Latest revision as of 06:40, 5 April 2020

Submapper is a term used in the NES 2.0 header for 4-bit codes designating functionally distinct variants of iNES mappers that cannot be distinguished by the memory size fields alone. Most emulators using iNES format distinguish these using CRC, SHA-1, or other hashes of the PRG ROM and CHR ROM, but this works only for games published prior to 1997, not for fan translations or ROM hacks, and not for new games on the same mapper.

Submapper 0 represents the default iNES behavour, so that backward compatibility is maintained with existing ROMs.

Submapper allocations that are listed as "deprecated" were assigned by kevtris' original proposal, but have no known use cases. The deprecation reserves these unused allocations to maintain continuity and compatibility.

This document is a living specification. Proposals for new submappers should be made at: Proposals.

001: MMC1

Most MMC1 boards are compatible with the standard mapper 1 behavior (submapper 0).

Boards with CHR-RAM usually reuse the CHR banking lines to address other things.

  • SUROM, SOROM, and SXROM implement extra PRG-ROM and PRG-RAM banking (deprecated submappers 1, 2, 4).
  • SNROM implements a redundant PRG-RAM enable (no assigned submapper).

The variant MMC1A chip was assigned to mapper 155 (deprecated submapper 3).

Most boards with 32k of PRG-ROM have no PRG banking: SEROM, SHROM, SH1ROM (submapper 5).

001: 0

Normal behavior.

001: 1, 2, 4 = SUROM, SOROM, SXROM

Deprecated.

These submappers are a redundancy. The difference between these boards and the "normal" MMC1 implementation is exclusively dependent on the sizes of CHR, PRG RAM, and PRG ROM. Because of this, the addition of PRG RAM to the NES 2.0 specification was enough to make these compatible with submapper 0.

These three boards used 8k CHR RAM, and reused the CHR banking bits to bank PRG ROM and RAM instead. The specific boards can be detected by these sizes, or simply emulated together in submapper 0:

$A000 and $C000:
4bit0
-----
EDCBA
|||||
||||+- CHR A12
|||+-- CHR A13, if extant (CHR >= 16k)
||+--- CHR A14, if extant; and PRG RAM A14, if extant (PRG RAM = 32k, submapper 4)
|+---- CHR A15, if extant; and PRG RAM A13, if extant (PRG RAM >= 16k, submappers 2, 4)
+----- CHR A16, if extant; and PRG ROM A18, if extant (PRG ROM = 512k, submappers 1, 4)

The following games are on SUROM (submapper 1):

SOROM (submapper 2):

SXROM (submapper 4):

If any NES 2.0 ROMs are found using these deprecated submappers, the CHR, PRG RAM, and PRG ROM sizes must appropriately match to be a valid header.

001: 3

Deprecated.

This originally described a submapper that was already implemented as iNES Mapper 155.

001: 5 Fixed PRG

SEROM, SHROM, SH1ROM use a fixed 32k PRG ROM with no banking support. (This is distinct from SIROM which has 32k of bankable PRG ROM.)

PRG ROM A14 is connected directly to CPU A14 (and MMC1 A14 input) instead of MMC1 A14 output.

Existing games are compatible with submapper 0 if $8000-BFFF is initialized to the low bank, and $C000-FFFF is initialized to the high bank. These boards were used in several games: SEROM SHROM SH1ROM

Test ROM:

002, 003, 007: UxROM, CNROM, AxROM

Mappers 2, 3, and 7 describe discrete logic mappers that are usually subject to bus conflicts. Most of these games are programmed in a way that does not rely on the bus conflict behaviour, but software bugs may expose the difference (e.g. Cybernoid[1]). Because these differences are obscure, the default iNES implementation for mappers 2 and 3 has been inconsistent across emulators, some with bus conflicts, some without. Mapper 7 is normally emulated without bus conflicts, because of a small number of games using the ANROM board which rely on this.

Two submappers allow this ambiguity to be resolved, by selecting a specific behaviour:

0: Default iNES behaviour (Emulators should warn the user and/or enforce bus conflicts for mappers 2 and 3, and should warn the user and/or fail to enforce bus conflicts for mapper 7)
1: Bus conflicts do not occur
2: Bus conflicts occur, producing the bitwise AND of the written value and the value in ROM

Although all Nintendo-manufactured games using normal CNROM (mapper 3), normal UxROM (mapper 2), and inverted UxROM (mapper 180) had bus conflicts, apparently several unlicensed games require their absence, as does the updated version of Donkey Kong with the pie factory level[2].

AxROM (mapper 7) is the only known licensed discrete logic mapper to unreliably come with bus conflict prevention circuitry. While no game documented in NesCartDB was released in one region on multiple board variants, several games did change boards when localized.

New ROMs are encouraged to specify submapper 2 to verify correct behaviour with bus conflicts.

CNROM with security diodes (mapper 185) has a different set of submapper definitions.

002: 0, 1, 2 UxROM

Test ROMs: (forum post)

  • 2_test_0.nes - Unspecified.
  • 2_test_1.nes - No bus conflicts.
  • 2_test_2.nes - AND bus conflicts.

003: 0, 1, 2 CNROM

Test ROMs: (forum post)

  • 3_test_0.nes - Unspecified.
  • 3_test_1.nes - No bus conflicts.
  • 3_test_2.nes - AND bus conflicts.

007: 0, 1, 2 AxROM

Test ROMs: (forum post)

  • 7_test_0.nes - Unspecified.
  • 7_test_1.nes - No bus conflicts.
  • 7_test_2.nes - AND bus conflicts.

004: MMC3

iNES Mapper 004 represents the most common boards using these four ICs: early MMC3, late MMC3, MC-ACC, and MMC6.

There are three known kinds of IRQ:

  1. MMC3A: IRQ is asserted on A12 rise, and loading the latch with 0 disables IRQ. Some chips labeled MMC3B also have this "old style" behavior. At least one unlicensed game relies on this behavior.
  2. MMC3C: IRQ is asserted on A12 rise, and loading the latch with 0 produces an IRQ on every scanline. Some chips labeled MMC3B also have this "new style" behavior, as does the MMC6. Some later games rely on this behavior.
  3. MC-ACC: IRQ is asserted on A12 fall, typically four pixels later than MMC3C. Interrupts can be produced every scanline, like the MMC3C.[3]

There are two known kinds of PRG RAM enable:

  1. MMC3: One set of enable bits controls the entire chip.
  2. MMC6: The first and second enables control the first and second half of PRG RAM, and an additional enable in bit 5 of $8000 controls the whole PRG RAM.

The TEROM and TFROM boards have two jumpers that can respectively disable IRQs and force hard-wired mirroring. It is believed that nothing was ever released that used them.

004: 0

Normal. (MMC3C)

004: 1 MMC6

MMC6 has an alternative PRG-RAM enable and write protection scheme designed for its internal 1k PRG RAM.

  • StarTropics
  • StarTropics 2

004: 2

Deprecated.

This originally described MMC3C with hard wired mirroring. No games are known to require this.

004: 3 MC-ACC

MC-ACC

The MC-ACC is found in 13 second-source PCBs manufactured by Acclaim:

  • Alien³
  • George Foreman's KO Boxing
  • The Incredible Crash Dummies
  • Mickey's Safari in Letterland
  • Roger Clemens' MVP Baseball
  • Rollerblade Racer
  • The Simpsons: Bart vs. The World
  • The Simpsons: Bartman Meets Radioactive Man
  • Spider-Man: Return of the Sinister Six
  • T&C Surf Designs 2: Thrilla's Surfari
  • T2: Terminator 2: Judgment Day
  • WWF King of the Ring
  • WWF WrestleMania: Steel Cage Challenge

004: 4 MMC3A

Loading the latch with 0 disables IRQ.

  • SuperGame's Aladdin (Mapper 4 version)

016: Bandai FCG board

INES Mapper 016 submapper table
Submapper # Meaning Note
0 Unspecified Emulate both FCG-1/2 and LZ93D50 chips in their respective CPU address ranges.
1 LZ93D50 with 128 byte serial EEPROM (24C01) Deprecated, use INES Mapper 159 instead.
2 Datach Joint ROM System Deprecated, use INES Mapper 157 instead.
3 8 KiB of WRAM instead of serial EEPROM Deprecated, use INES Mapper 153 instead.
4 FCG-1/2 Responds only in the CPU $6000-$7FFF address range; IRQ counter is not latched.
5 LZ93D50 with no or 256-byte serial EEPROM (24C02) Responds only in the CPU $8000-$FFFF address range; IRQ counter is latched.

019: Namco 129/163

The NES 2.0 submapper is used to specify the mixing resistor that determines the relative volume of the expansion audio channels against the APU's audio channels:

INES Mapper 019 submapper table
Submapper # Meaning Note
0 Default Expansion sound volume unspecified
1 Deprecated Internal 128b RAM is battery backed, no external PRG-RAM is present.

No expansion sound. (Equivalent to submapper 2 with 0 in PRG-NVRAM field.)

2 No expansion sound
3 N163 expansion sound: 11.0-13.0 dB louder than NES APU
4 N163 expansion sound: 16.0-17.0 dB louder than NES APU
5 N163 expansion sound: 18.0-19.5 dB louder than NES APU

021, 023, 025: VRC2 / VRC4

These three mappers collect various configurations of VRC2 and VRC4 boards.

VRC2 is mostly a subset of VRC4, with differences including:

  • VRC2 has a serial EEPROM interface which no Konami game ever connected an actual EEPROM to, but one PCB is wired so that it functions as a single bit of memory mapped at $6000-6FFF[4]
  • VRC4 supports horizontal, vertical and one-screen nametable mirroring while VRC2 supports only horizontal and vertical mirroring[5]
  • VRC4 supports two PRG ROM banking modes, similar to MMC3's. VRC2 only has one PRG ROM banking mode.
  • VRC4 has an interrupt device that VRC2 does not.

Additionally, different boards connect the address lines for the registers in various arrangements. The three iNES mappers 21, 23, and 25 each combine multiple boards whose addresses overlap. This is enough for game compatibility, but it creates an ugly combination that does not accurately describe the original hardware of either board.

Submapper assignment

Konami's VRC2 and VRC4 mappers have several variations of how the board connects low CPU address lines among A7-A0 to the port select lines of the mapper. Mappers 21, 23 and 25 each combine two non-overlapping addressing variations, and neglect to specify VRC2 vs VRC4.

Mapper 22 is related, but only supports one variation (VRC2a) and has a different CHR banking arrangement than the others. It does not require submapper disambiguation.

There are three variations of the VRC2 boards, and five of VRC4:

VRC2
Nickname PCB A0 A1 Registers iNES mapper submapper
VRC2a 351618 A1 A0 $x000, $x002, $x001, $x003 22 0
VRC2b many A0 A1 $x000, $x001, $x002, $x003 23 3
VRC2c 351948 A1 A0 $x000, $x002, $x001, $x003 25 3
VRC4
Nickname PCB A0 A1 Registers iNES mapper submapper
VRC4a 352398 A1 A2 $x000, $x002, $x004, $x006 21 1
VRC4b 351406 A1 A0 $x000, $x002, $x001, $x003 25 1
VRC4c 352889 A6 A7 $x000, $x040, $x080, $x0C0 21 2
VRC4d 352400 A3 A2 $x000, $x008, $x004, $x00C 25 2
VRC4e 352396 A2 A3 $x000, $x004, $x008, $x00C 23 2
VRC4f - A0 A1 $x000, $x001, $x002, $x003 23 1
The VRC2b PCBs include: 350603, 350636, 350926, 351179

This submapper assigment uses the following symmetrical arrangement:

  • 0. Both addressing
  • 1. Lower addressing, VRC4
  • 2. Higher addressing, VRC4
  • 3. Lower addressing, VRC2 (no known examples for mapper 21)
  • 4. Higher addressing, VRC2 (no known examples)

021 / 023 / 025: 0

The default implementation acts as a VRC4 (mostly compatible superset of VRC2), and responds to register writes in one or more configurations simultaneously (supporting both boards at once).

021 / 023 / 025: 1, 2 VRC4

These allocations each request a single specific addressing scheme for VRC4, rather than the combined version used by submapper 0.

  • 021: 1 VRC4a
  • 025: 1 VRC4b
  • 021: 2 VRC4c
  • 025: 2 VRC4d
  • 023: 2 VRC4e
  • 023: 1 VRC4f

023: 1 VRC4f

Some unlicensed games used a second-source VRC4 clone with register addressing identical to VRC2b (the simplest contiguous in-order interpretation: 0,1,2,3). This was used in World Hero.

023: 3 VRC2b

Games on PCB 350926 (and its chip-on-board equivalents) rely on a single bit of RAM mapped in the region from $6000-$6FFF. Prior to NES 2.0, these games were supported by implementing WRAM in this region (despite this board not having WRAM). This board was used in Contra (J), Ganbare Goemon 2 and Konami Wai Wai World.

There are other VRC2 boards with the same register addressing as 350926 but without this feature ($6000-$6FFF is effectively open bus on them), but no game relies on the lack of the single bit of memory, so a separate submapper has not been allocated for them. These boards were used in Dragon Scroll, Getsu Fuuma Den, and Jarinko Chie.

Since this submapper represents VRC2, it should not implement the VRC4-only one-screen mirroring, PRG ROM banking modes, or IRQ capabilities. Wai Wai World depends on the lack of one-screen mirroring; it will have corrupt backgrounds in the vertically-scrolling stages and the ending if emulated with VRC4 capabilities.

025: 3 VRC2c

Ganbare Goemon Gaiden: Kieta Ougon Kiseru uses the same register addressing as VRC4b, but is VRC2, so this submapper should not implement VRC4-only capabilities.

Test ROMs

032: Irem G101

A variation of this mapper requires hardwired one-screen mirroring and entirely ignores writes to $9000.

032: 0

Normal (H/V mapper-controlled mirroring)

032: 1 Major League

CIRAM A10 is tied high (fixed one-screen mirroring) and PRG banking style is fixed as 8+8+16F

034: BNROM / NINA-001

This iNES mapper unfortunately combines the unrelated BNROM and NINA-001 mappers.

034: 0

Normal.

To disambiguate the two mappers, emulators have taken various approaches:

  • The presense of CHR larger than 8 KiB unambiguously requires NINA-001, as BNROM has no CHR banking.
  • The presence of CHR-RAM is taken to imply BNROM, because both extant BNROM games use CHR-RAM.
  • CRC tests may be used to select a mapper for previously known ROMs.
  • Implement both mappers simultaneously. This is compatible with existing games.

Selecting a single implementation based on CHR results in greater accuracy, since no game was ever intended for the combined definition.

New programs should not attempt to use a combined BNROM + NINA-001 mapper because this is not reliably available across emulators. Unusual combinations like NINA-001 with CHR-RAM are theoretically possible, but unlikely to be emulated consistently.

034: 1 NINA-001

NINA-001 only.

Test ROM: (forum post)

  • 34_test_1.nes - NINA-001 with CHR ROM.

034: 2 BNROM

BNROM only.

Some unlicensed boards by Union Bond were a variation of BNROM that included PRG RAM. These may also use this submapper if PRG RAM is specified in the NES 2.0 header.

Test ROM: (forum post)

  • 34_test_2.nes - BNROM with CHR RAM.

068: Sunsoft 4

In addition to its normal function, the Sunsoft 4 IC was used in Nantettatte!! Baseball, which allowed a second expansion cartridge to be plugged into it.

068: 0

0: Normal (max 256KiB PRG)

068: 1 Dual Cartridge System

1: Sunsoft Dual Cartridge System a.k.a. NTB-ROM (max 128KiB PRG, licensing IC present, external option ROM of up to 128KiB should be selectable by a second menu)

071: Codemasters

Some games use this with 1-screen mirroring, where the mapper's mirroring control bit is wired directly to CIRAM A10. Others have hardwired horizontal or vertical mirroring.

Another variation of this mapper was used in the Quattro multicarts, but these have been reassigned to mapper 232.

071: 0

Hardwired horizontal or vertical mirroring.

071: 1 Fire Hawk

Mapper controlled single-screen mirroring.

078: Cosmo Carrier / Holy Diver

This mapper unfortunately combines two games with incompatible mirroring control.

One game uses this with 1-screen mirroring, where the mapper's mirroring control bit is wired directly to CIRAM A10. The other can switch between horizontal and vertical mirroring, using a multiplexer between PPU A10 and PPU A11 whose output is sent to CIRAM A10.

078: 0

Unspecified.

078: 1 Cosmo Carrier

Single-screen mirroring (nibble-swapped mapper 152).

078: 2

Deprecated.

This described a variation with fixed vertical mirroring, and WRAM. There is no known use case.

078: 3 Holy Diver

Mapper-controlled H/V mirroring.

085: Konami VRC7

  • VRC7b uses A3 to select registers ($x008), used in Tiny Toon Adventures (Submapper 1).
  • VRC7a uses A4 to select registers ($x010), used in Lagrange Point (Submapper 2).

091: Super Fighter III

  • Submapper 0: YY830624C/JY830848C (J.Y. Company clone board)
  • Submapper 1: EJ-006-1 (original Super Fighter III board).

114: Sugar Softec/Hosenkan, fixed MMC3 scrambling pattern

Registers at $6000 (and $6001, although not used for effect by existing games)

  • Submapper 0: The Lion King, Aladdin
  • Submapper 1: Boogerman (different scrambling pattern)

178.1: Gameinis Infrared Sensor

  • Submapper 0: No infrared sensor present
  • Submapper 1: Gameinis Infrared Sensor present

185: CNROM used to selectively disable CHR-ROM

A few NROM-like games were released on CNROM boards where all four bits of the latch were solely used as an anti-piracy measure. Games would check that CHR-ROM is disabled unless the latch holds the correct one of the four possible bank values. See this thread for test ROMs and example implementation code.

185: 0

Correct bank value unknown. A heuristic that works with all known games that use this mapper is to return $FF on the first two reads from CPU $2007 after a reset.

185: 4

Enable CHR-ROM if bits 0..1 of the latch hold the value 0, otherwise disable CHR-ROM.

185: 5

Enable CHR-ROM if bits 0..1 of the latch hold the value 1, otherwise disable CHR-ROM.

185: 6

Enable CHR-ROM if bits 0..1 of the latch hold the value 2, otherwise disable CHR-ROM.

185: 7

Enable CHR-ROM if bits 0..1 of the latch hold the value 3, otherwise disable CHR-ROM.

210: Namco 175 and 340

Mapper 210 doesn't distinguish between the 175's hardwired mirroring and 340's 1/H/V mirroring.

Also, previous confusion and compatibility code used by Namco when they were developing games means that many 175- and 340- using games are incorrectly tagged as mapper 19.

210: 0

No advisory statement is made (use runtime heuristics suggested at mapper 210)

210: 1 N175

Namco 175. Hardwired mirroring, no IRQ.

  • Dream Master
  • Famista '91
  • Family Circuit '91
  • Chibi Maruko-chan: Uki Uki Shopping
  • Heisei Tensai Bakabon / Genius Bakabon

210: 2 N340

Namco 340. 1/H/V mirroring, no IRQ, no internal or external RAM.

  • Splatterhouse
  • Wagyan Land 2
  • Famista '92
  • Top Striker
  • Wagyan Land 3
  • Famista '93
  • Famista '94

215: Sugar Softec, selectable MMC3 scrambling pattern

Registers at $5000-$5007.

  • Submapper 0: UNL-8237 (two non-overlapping outer bank bits for PRG/CHR each)
  • Submapper 1: UNL-8237A (three overlapping outer bank bits for PRG/CHR each)

232: Quattro

Similar to #71 above, with a separate register controlling which 64 KiB outer bank of the PRG ROM is used. This is used for the Quattro multicarts.

The Aladdin Deck Enhancer version of these multicarts used a different banking scheme.

232: 0

0: Normal

232: 1 Aladdin Deck Enhancer

Aladdin Deck Enhancer variation. Swap the bits of the outer bank number.

  • Quattro Adventure (Aladdin Deck Enhancer)
  • Quattro Sports (Aladdin Deck Enhancer)
  • Pegasus 4-in-1
  • Super Adventure Quests (European release of Quattro Adventure)

NES 2.0 Mapper 256

Several plug-and-play consoles use a simple protection scheme intended to prevent interchanging the ROM data between different consoles. The protection scheme works by simply swapping the addresses of the bankswitch registers. Some patterns only change the VTxx-native register addresses, others apply to the MMC3 compatibility registers as well.

Other plug-and-play consoles, in particular those by Jungletac, scramble CPU opcode bytes (and only those) by swapping bits. These consoles power-on with opcode scrambling enabled, but allow it to be disabled --- for example, to run a pirated licensed NES game without modifying it --- by writing to a register.

Submapper # Name PPU bank affected by ... CPU bank affected by ... CPU opcode bytes
$2012 $2013 $2014 $2015 $2016 $2017 $8000.0 $8000.1 $8000.2 $8000.3 $8000.4 $8000.5 $4107 $4108 $8000.6 $8000.7
0 Normal $1000 $1400 $1800 $1C00 $0000 $0800 $0000 $0800 $1000 $1400 $1800 $1C00 $8000 $A000 $8000 $A000 none
1 Waixing VT03 $1400 $1000 $0800 $0000 $1C00 $1800 $1C00 $1800 $1400 $1000 $0800 $0000 $8000 $A000 $8000 $A000 none
2 Power Joy Supermax $1000 $1400 $1800 $1C00 $0000 $0800 $0000 $0800 $1000 $1400 $1800 $1C00 $A000 $8000 $A000 $8000 none
3 Zechess/Hummer Team $0800 $0000 $1C00 $1800 $1000 $1400 $0000 $0800 $1000 $1400 $1800 $1C00 $8000 $A000 $8000 $A000 none
4 Sports Game 69-in-1 $1800 $0800 $1000 $0000 $1C00 $1400 $0000 $0800 $1000 $1400 $1800 $1C00 $8000 $A000 $8000 $A000 none
5 Waixing VT02 $1400 $1000 $0800 $0000 $0000 $0800 $0000 $0800 $1000 $1400 $1800 $1C00 $8000 $A000 $8000 $A000 none
13 Cube Tech $1000 $1400 $1800 $1C00 $0000 $0800 $0000 $0800 $1000 $1400 $1800 $1C00 $8000 $A000 $8000 $A000 D1 and D4 swapped, switched via $4169
14 Karaoto $1000 $1400 $1800 $1C00 $0000 $0800 $0000 $0800 $1000 $1400 $1800 $1C00 $8000 $A000 $8000 $A000 D6 and D7 swapped, switched via $411C
15 Jungletac $1000 $1400 $1800 $1C00 $0000 $0800 $0000 $0800 $1000 $1400 $1800 $1C00 $8000 $A000 $8000 $A000 D5 and D6 swapped, switched via $4169

268: Coolboy/Mindkids

  • Submapper 0: Coolboy (outer bank registers at $6000-$6003)
  • Submapper 1: Mindkids (outer bank registers $5000-$5003)

References

  1. NESDev post explaining Cybernoid's bugs.
  2. Nintendoage thread discussing Donkey Kong Pie Factory.
  3. MC-ACC IRQ test results
  4. http://forums.nesdev.com/viewtopic.php?t=8274 VRC2 memory bit at $6000-$6FFF
  5. http://forums.nesdev.com/viewtopic.php?t=13473 VRC2 mirroring selection tested on hardware