INES Mapper 176: Difference between revisions
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{{DEFAULTSORT:176}}[[Category:iNES Mappers]][[Category:Multicart mappers]][[Category:MMC3-like mappers]][[Category:MMC3 with CHR ROM and CHR RAM]][[Category:Mappers with scanline IRQs]][[Category:Mappers with large PRG RAM]][[Category:NES 2.0 mappers with submappers]] | {{DEFAULTSORT:176}}[[Category:iNES Mappers]][[Category:Multicart mappers]][[Category:MMC3-like mappers]][[Category:MMC3 with CHR ROM and CHR RAM]][[Category:Mappers with scanline IRQs]][[Category:Mappers with large PRG RAM]][[Category:NES 2.0 mappers with submappers]] | ||
'''iNES Mapper 176''' denotes | '''iNES Mapper 176''' denotes the '''8025''' enhanced [[MMC3]] chipset. It used by many multicarts, Chinese single-game and educational computer cartridges, and Techno Source's ''Intellivision X2'' Plug-and-Play console. Incompatible variations exist that are denoted via NES 2.0 Submapper. | ||
{| class="wikitable" | |||
! colspan="13" | Submappers | |||
|- | |||
! rowspan="2" | # !! rowspan="2" | PCB codes !! rowspan="2" | [[UNIF]] MAPR !! colspan="5" | MMC3 !! colspan="4" | Outer bank registers !! rowspan="2" | Example | |||
|- | |||
! Ext. mode !! PRG bits !! $46/47 !! [[Mirroring#Single-Screen|1SM]] !! Extra WRAM !! Address mask !! PRG A21+ !! CHR A21+ !! CNROM latch | |||
|- | |||
| 0 || LP-8002KB, SFC-12B || '''BMC-Super24in1SC03''' || - || 6 || normal || - || - || $Fxx3 || - || - || - || ''YH-xxx'' multicarts, ''Rockman 6-in-1'' | |||
|- | |||
| 1 || FK-xxx/BS-xxx || '''BMC-FK23C'''/'''BMC-FK23CA''' || $5FF3.1 || 8 || normal || - || - || $Fxx3 || - || - || yes || ''FK-xxxx'' multicarts | |||
|- | |||
| 2 || FS005/FS006 || '''WAIXING-FS005''' || $5FF3.1 || 6 || swapped || yes || $A001.0-1 || $Fxx3 || $5xx0.3/7, $5xx2.6-7/5 || - || - || Waixing 2005+ re-releases, ''245-in-1 Real Game'' | |||
|- | |||
| 3 || JX9003B || - || - || 8 || normal || - || - || $Fxx7 || $5xx5 || $5xx6 || - || ''Super Mario 160-in-1 Funny Time'' | |||
|- | |||
| 4 || ? || - || - || 6 || normal || - || - || $Fxx3 || $5xx2.7 || - || - || ''GameStar Smart Genius Deluxe'' | |||
|- | |||
| 5 || HST-162|| - || - || 6 || normal || - || - || $Fxx3 || $4800 || - || - || ''Game 500-in-1'' | |||
|- | |||
|} | |||
* The '''SFC-12B''' PCB (submapper 0) mounts both CHR-ROM and CHR-RAM that are selected via $5xx0.5. | |||
* Eight MMC3 PRG bits mean that bit 6 and 7 of $8000.6/7 are applied, and the fixed banks are $FE/$FF rather than $3E/$3F. This implies that the multicart's reset vector lies at address PRG-ROM address $1FFFFC rather than $7FFFC if the PRG-ROM is that large. | |||
=Registers= | =Registers= | ||
'''FS005 (Submapper 2)''' can disable the registers in the $5000-$5FFF range using the [[#RAM Configuration Register ($A001)|RAM Configuration Register ($A001)]]. The same register also enables a mixed CHR-ROM/CHR-RAM mode that is similar to [[INES Mapper 195]]. | |||
==Mode Register ($5xx0)== | ==Mode Register ($5xx0)== | ||
Mask: $5''xx''3, ''x'' determined by [[#Solder Pad|solder pad setting]] | Mask: $F''xx''7 ('''Submapper 3'''), $5''xx''3 (all others), ''x'' determined by [[#Solder Pad|solder pad setting]] | ||
7654 3210 | 7654 3210 | ||
---- ---- | ---- ---- | ||
Line 19: | Line 34: | ||
|||| |||| | |||| |||| | ||
|||| |+++- Select PRG Banking Mode (ignored in Extended MMC3 Mode) | |||| |+++- Select PRG Banking Mode (ignored in Extended MMC3 Mode) | ||
|||| | 0: MMC3 PRG Mode, 512 KiB Outer PRG Bank Size | |||| | 0: MMC3 PRG Mode, 2 MiB/512 KiB Outer PRG Bank Size | ||
|||| | 1: MMC3 PRG Mode, 256 KiB Outer PRG Bank Size | |||| | 1: MMC3 PRG Mode, 256 KiB Outer PRG Bank Size | ||
|||| | 2: MMC3 PRG Mode, 128 KiB Outer PRG Bank Size | |||| | 2: MMC3 PRG Mode, 128 KiB Outer PRG Bank Size | ||
|||| | 3: NROM-128 PRG Mode, 16 KiB PRG at $8000-$BFFF mirrored at $C000-$FFFF | |||| | 3: NROM-128 PRG Mode, 16 KiB PRG at $8000-$BFFF mirrored at $C000-$FFFF | ||
|||| | 4: NROM-256 PRG Mode, 32 KiB PRG at $8000-$FFFF | |||| | 4: NROM-256 PRG Mode, 32 KiB PRG at $8000-$FFFF | ||
|||| | 5-7: Never used | |||| | 5: UNROM PRG Mode, 16 KiB PRG at $8000-$BFFF, inner bank #7 at $C000-$FFFF | ||
|||| +---- PRG | |||| | 6-7: Never used | ||
|||| +---- PRG A21 ('''Submapper 2''' only) | |||
|||+------ Select Outer CHR Bank Size | |||+------ Select Outer CHR Bank Size | ||
||| 0: In MMC3 CHR Mode: 256 KiB | ||| 0: In MMC3 CHR Mode: 256 KiB | ||
||| In CNROM CHR Mode: 32 KiB | ||| In CNROM CHR Mode: 32 KiB ('''Submapper 1''' only) | ||
||| 1: In MMC3 CHR Mode: 128 KiB | ||| 1: In MMC3 CHR Mode: 128 KiB | ||
||| In CNROM CHR Mode: 16 KiB | ||| In CNROM CHR Mode: 16 KiB ('''Submapper 1''' only) | ||
||+------- | ||+------- '''Submappers 0/1''' with both CHR-ROM and CHR-RAM (e.g. '''SFC-12B''' PCB): | ||
|| 0: CHR-ROM | || 0: Select CHR-ROM | ||
|| 1: CHR-RAM | || 1: Select CHR-RAM | ||
|+-------- CHR Mode | || '''Submapper 1''' with $5xx0.6=1: | ||
| 0: MMC3 | || 0: Enable CNROM latch (CNROM mode) | ||
| 1: | || 1: Disable CNROM latch (NROM mode) | ||
+--------- PRG | |+-------- CHR A10-12 Mode | ||
| 0: from MMC3 | |||
| 1: from PPU | |||
+--------- PRG A22 ('''Submapper 2''' only) | |||
Power-on value: $00 | Power-on value: $00 | ||
==PRG Base Register LSB ($5xx1)== | |||
Mask: $F''xx''7 ('''Submapper 3'''), $F''xx''3 (all others), ''x'' determined by [[#Solder Pad|solder pad setting]] | |||
7654 3210 | 7654 3210 | ||
---- ---- | ---- ---- | ||
.PPP PPPP | .PPP PPPP | ||
||| |||| | ||| |||| | ||
+++-++++- PRG | +++-++++- PRG A20..A14 | ||
Power-on value: $00 | |||
Depending on the PRG banking mode set via $5xx0, only the higher bits of this register are applied: | |||
PRG A.. | |||
21111111 | |||
09876543 | |||
-------- | |||
MMMMMMMM Submappers 1/3 in PRG Mode 0 (MMC3 2 MiB) or Extended MMC3 Mode | |||
BBMMMMMM Submappers 0/2/4 in PRG Mode 0 (MMC3 512 KiB) | |||
BBBMMMMM PRG Mode 1 (MMC3 256 KiB) | |||
BBBBMMMM PRG Mode 2 (MMC3 128 KiB) | |||
BBBBBBBC PRG Mode 3 (NROM-128) | |||
BBBBBBCC PRG Mode 4 (NROM-256) | |||
BBBBLLLC PRG Mode 5 (UNROM) | |||
M: Bit comes from MMC3 ($8000.6/7 or fixed bank) | |||
B: Bit comes from PRG Base Register ($5xx1) | |||
L: Bit comes from UNROM Latch ($8000-$FFFF or fixed bank) | |||
C: Bit comes from CPU | |||
'''Submapper 5''' only selects PRG A14-A18 (i.e. 512 KiB) via this register, selecting upper PRG bits via register [[#PRG Base Register MSB ($4800), Submapper 5 only|$4800]]. | |||
==PRG Base Register MSB ($5xx5), Submapper 3 only== | |||
Mask: $F''xx''7 ('''Submapper 3'''), ''x'' determined by [[#Solder Pad|solder pad setting]] | |||
7654 3210 | |||
---- ---- | |||
.... PPPP | |||
|||| | |||
++++- PRG Base A24..A21 | |||
Power-on value: $00 | |||
==PRG Base Register MSB ($4800), Submapper 5 only== | |||
Mask: $F800 | |||
7654 3210 | |||
---- ---- | |||
..PP PPPP | |||
|| |||| | |||
++-++++- PRG Base A24..A19 | |||
Power-on value: $00 | Power-on value: $00 | ||
==CHR Base Register LSB ($5xx2)== | |||
Mask: $F''xx''7 ('''Submapper 3'''), $5''xx''3 (all others), ''x'' determined by [[#Solder Pad|solder pad setting]] | |||
7654 3210 | 7654 3210 | ||
---- ---- | ---- ---- | ||
ccdC CCCC | ccdC CCCC | ||
|||| |||| | |||| |||| | ||
++++-++++- CHR | ++++-++++- CHR A20..A13 | ||
||+------- PRG | ||+------- PRG A25 ('''Submapper 2''' only) | ||
++-------- PRG | ++-------- PRG A24..A23 ('''Submapper 2''' only) | ||
+--------- PRG A21 ('''Submapper 4''') | |||
Power-on value: $00 | Power-on value: $00 | ||
== | Depending on the CHR banking mode set via $5xx0, only the higher bits of this register are applied: | ||
Mask: $ | CHR A.. | ||
21111111111 | |||
09876543210 | |||
----------- | |||
BBBMMMMMMMM MMC3 CHR Mode ($5xx0.6=0), 256 KiB ($5xx0.4=0) | |||
BBBBMMMMMMM MMC3 CHR Mode ($5xx0.6=0), 128 KiB ($5xx0.4=1) | |||
BBBBBBLLPPP CNROM CHR Mode ($5xx0.6=1, $5xx0.5=0), 32 KiB ($5xx0.4=0), '''Submapper 1''' only | |||
BBBBBBBLPPP CNROM CHR Mode ($5xx0.6=1, $5xx0.5=0), 16 KiB ($5xx0.4=1), '''Submapper 1''' only | |||
BBBBBBBBPPP NROM CHR Mode ($5xx0.6=1, $5xx0.5=1 or '''Submapper''' other than '''1''') | |||
M: Bit comes from MMC3 ($8000.0-5) | |||
B: Bit comes from CHR Base Register ($5xx2) | |||
L: Bit comes from CNROM Latch ($8000-$FFFF) | |||
P: Bit comes from PPU | |||
==CHR Base Register MSB ($5xx6), Submapper 3 only== | |||
Mask: $F''xx''7 ('''Submapper 3'''), ''x'' determined by [[#Solder Pad|solder pad setting]] | |||
7654 3210 | 7654 3210 | ||
---- ---- | ---- ---- | ||
. | .... PPPP | ||
|||| | |||
++++- CHR Base A24..A21 | |||
Power-on value: | Power-on value: $00 | ||
==Extended Mode Register ($5xx3), Submappers 1-2 only== | |||
Mask: $F''xx''3, ''x'' determined by [[#Solder Pad|solder pad setting]] | |||
7654 3210 | |||
---- ---- | |||
.?.. .?E. | |||
| | |||
+- [[#MMC3-compatible registers ($8000/$8001, $A000, $C000/$C001, $E000/$E001)|Extended MMC3 Mode]] | |||
0: disable | |||
1: enable | |||
Power-on value: $00 | |||
Most multicarts write value $44 rather than $00 to disable Extended MMC3 Mode. Hardware tests do not indicate any difference in behavior between writing $00 and $44. | |||
==Mirroring Register ($A000)== | ==Mirroring Register ($A000)== | ||
Mask: $ | Mask: $E003 | ||
7654 3210 | 7654 3210 | ||
Line 99: | Line 169: | ||
0: Vertical | 0: Vertical | ||
1: Horizontal | 1: Horizontal | ||
2: Single-screen, page 0 | 2: Single-screen, page 0 ('''Submapper 2''' only) | ||
3: Single-screen, page 1 | 3: Single-screen, page 1 ('''Submapper 2''' only) | ||
Power-on value: $00 | Power-on value: $00 | ||
Single-screen mirroring is only available when the RAM Configuration Register is enabled ($A001.5). | Single-screen mirroring is only available when the RAM Configuration Register is enabled ($A001.5). | ||
==RAM Configuration Register ($A001)== | ==RAM Configuration Register ($A001), Submapper 2 only== | ||
Mask: $ | Mask: $E003 | ||
This register functions like MMC3 register $A001 until bit 5 is set, which turns it into the RAM Configuration Register | This register functions like MMC3 register $A001 until bit 5 is set, which turns it into the RAM Configuration Register. | ||
7654 3210 | 7654 3210 | ||
Line 122: | Line 192: | ||
|| 0: RAM Configuration Register disabled, $A001 functions as on MMC3, 8 KiB of WRAM | || 0: RAM Configuration Register disabled, $A001 functions as on MMC3, 8 KiB of WRAM | ||
|| 1: RAM Configuration Register enabled, 32 KiB of WRAM | || 1: RAM Configuration Register enabled, 32 KiB of WRAM | ||
|+-------- | |+-------- Outer Bank Registers Enable. Ignored if Bit 5 is clear. | ||
| 0: | | 0: Outer Bank Registers disabled, $5000-$5FFF maps to the second 4 KiB of the 8 KiB WRAM bank 2 | ||
| 1: | | 1: Outer Bank Registers enabled in the $5000-$5FFF range | ||
+--------- PRG RAM enable (0: disable, 1: enable) | +--------- PRG RAM enable (0: disable, 1: enable) | ||
Power-on value: $00 | Power-on value: $00 | ||
== | |||
In CNROM Mode, writing to | ==UNROM latch ($8000-$FFFF)== | ||
In UNROM Mode (PRG Mode 5), writing to this address range changes the 16 KiB inner PRG bank at $8000-$BFFF. | |||
==CNROM latch ($8000-$FFFF), Submapper 1 only== | |||
In CNROM Mode, writing to this address range changes the inner CHR bank. | |||
==MMC3-compatible registers, Extended MMC3 Mode ($8000/$8001, $C000/$C001, $E000/$E001)== | ==MMC3-compatible registers, Extended MMC3 Mode ($8000/$8001, $C000/$C001, $E000/$E001)== | ||
If the "Extended MMC3 Mode" bit in register $5xx3 is clear, then these registers function identically to the [[MMC3]]. | Mask: $E003 (verified on real hardware) | ||
Register $8000 if $5xx3 bit 1 is set | |||
Some multicart games depend on writes to $9FFF not doing anything as a result of the MMC3 address mask being $E003 rather than the standard $E001. | |||
If the "Extended MMC3 Mode" bit in register $5xx3 is clear, then these registers function identically to the [[MMC3]]. On '''Submappers 1 and 2''', if the "Extended MMC3 Mode" bit is set, four more bank registers become available at [[MMC3#Bank_select_.28.248000-.249FFE.2C_even.29|$8000/$8001]], so that the original two 2 KiB CHR banks become four 1 KiB CHR banks, and the two fixed 8 KiB PRG banks become selectable, similar to the [[RAMBO-1]]. Register $8000 if $5xx3 bit 1 is set: | |||
7 bit 0 | 7 bit 0 | ||
---- ---- | ---- ---- | ||
Line 157: | Line 234: | ||
* Standard MMC3 Registers $0-$7: $00, $02, $04, $05, $06, $07, $00, $01 | * Standard MMC3 Registers $0-$7: $00, $02, $04, $05, $06, $07, $00, $01 | ||
* Extended MMC3 Registers $8-$B: $FE, $FF, $FF, $FF | * Extended MMC3 Registers $8-$B: $FE, $FF, $FF, $FF | ||
=Solder Pad= | =Solder Pad= | ||
The address mask in the $5000-$5FFF range is determined by the solder pad setting: | The address mask in the $5000-$5FFF range is determined by the solder pad setting: | ||
Line 172: | Line 250: | ||
* Some multicarts only display their menu at settings other than 0. | * Some multicarts only display their menu at settings other than 0. | ||
=Protection= | =Protection (Submapper 2 only)= | ||
Later Waixing games (and re-releases of earlier games) use the RAM Configuration Register for copy-protection purposes: | Later Waixing games (and re-releases of earlier games) use the RAM Configuration Register for copy-protection purposes: | ||
* Write $A1 to $A001: Address range $5000-$5FFF to second half of 8 KiB WRAM bank 2, mapper registers there are disabled. | * Write $A1 to $A001: Address range $5000-$5FFF to second half of 8 KiB WRAM bank 2, mapper registers there are disabled. | ||
Line 182: | Line 260: | ||
* Execute code at CPU $0100. | * Execute code at CPU $0100. | ||
Hacked ROMs can be detected by them writing to $5000/$5010/$5013 but then no longer jumping to $0100. | Hacked ROMs can be detected by them writing to $5000/$5010/$5013 but then no longer jumping to $0100. | ||
=See also= | |||
* [[NES 2.0 Mapper 523]] is a variant of this mapper with hard-wired mirroring that connects CHR-ROM differently to produce 4/2 KiB instead of 2/1 KiB banks. |
Latest revision as of 18:48, 17 December 2021
iNES Mapper 176 denotes the 8025 enhanced MMC3 chipset. It used by many multicarts, Chinese single-game and educational computer cartridges, and Techno Source's Intellivision X2 Plug-and-Play console. Incompatible variations exist that are denoted via NES 2.0 Submapper.
Submappers | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
# | PCB codes | UNIF MAPR | MMC3 | Outer bank registers | Example | |||||||
Ext. mode | PRG bits | $46/47 | 1SM | Extra WRAM | Address mask | PRG A21+ | CHR A21+ | CNROM latch | ||||
0 | LP-8002KB, SFC-12B | BMC-Super24in1SC03 | - | 6 | normal | - | - | $Fxx3 | - | - | - | YH-xxx multicarts, Rockman 6-in-1 |
1 | FK-xxx/BS-xxx | BMC-FK23C/BMC-FK23CA | $5FF3.1 | 8 | normal | - | - | $Fxx3 | - | - | yes | FK-xxxx multicarts |
2 | FS005/FS006 | WAIXING-FS005 | $5FF3.1 | 6 | swapped | yes | $A001.0-1 | $Fxx3 | $5xx0.3/7, $5xx2.6-7/5 | - | - | Waixing 2005+ re-releases, 245-in-1 Real Game |
3 | JX9003B | - | - | 8 | normal | - | - | $Fxx7 | $5xx5 | $5xx6 | - | Super Mario 160-in-1 Funny Time |
4 | ? | - | - | 6 | normal | - | - | $Fxx3 | $5xx2.7 | - | - | GameStar Smart Genius Deluxe |
5 | HST-162 | - | - | 6 | normal | - | - | $Fxx3 | $4800 | - | - | Game 500-in-1 |
- The SFC-12B PCB (submapper 0) mounts both CHR-ROM and CHR-RAM that are selected via $5xx0.5.
- Eight MMC3 PRG bits mean that bit 6 and 7 of $8000.6/7 are applied, and the fixed banks are $FE/$FF rather than $3E/$3F. This implies that the multicart's reset vector lies at address PRG-ROM address $1FFFFC rather than $7FFFC if the PRG-ROM is that large.
Registers
FS005 (Submapper 2) can disable the registers in the $5000-$5FFF range using the RAM Configuration Register ($A001). The same register also enables a mixed CHR-ROM/CHR-RAM mode that is similar to INES Mapper 195.
Mode Register ($5xx0)
Mask: $Fxx7 (Submapper 3), $5xx3 (all others), x determined by solder pad setting
7654 3210 ---- ---- PCTm PMMM |||| |||| |||| |+++- Select PRG Banking Mode (ignored in Extended MMC3 Mode) |||| | 0: MMC3 PRG Mode, 2 MiB/512 KiB Outer PRG Bank Size |||| | 1: MMC3 PRG Mode, 256 KiB Outer PRG Bank Size |||| | 2: MMC3 PRG Mode, 128 KiB Outer PRG Bank Size |||| | 3: NROM-128 PRG Mode, 16 KiB PRG at $8000-$BFFF mirrored at $C000-$FFFF |||| | 4: NROM-256 PRG Mode, 32 KiB PRG at $8000-$FFFF |||| | 5: UNROM PRG Mode, 16 KiB PRG at $8000-$BFFF, inner bank #7 at $C000-$FFFF |||| | 6-7: Never used |||| +---- PRG A21 (Submapper 2 only) |||+------ Select Outer CHR Bank Size ||| 0: In MMC3 CHR Mode: 256 KiB ||| In CNROM CHR Mode: 32 KiB (Submapper 1 only) ||| 1: In MMC3 CHR Mode: 128 KiB ||| In CNROM CHR Mode: 16 KiB (Submapper 1 only) ||+------- Submappers 0/1 with both CHR-ROM and CHR-RAM (e.g. SFC-12B PCB): || 0: Select CHR-ROM || 1: Select CHR-RAM || Submapper 1 with $5xx0.6=1: || 0: Enable CNROM latch (CNROM mode) || 1: Disable CNROM latch (NROM mode) |+-------- CHR A10-12 Mode | 0: from MMC3 | 1: from PPU +--------- PRG A22 (Submapper 2 only) Power-on value: $00
PRG Base Register LSB ($5xx1)
Mask: $Fxx7 (Submapper 3), $Fxx3 (all others), x determined by solder pad setting
7654 3210 ---- ---- .PPP PPPP ||| |||| +++-++++- PRG A20..A14 Power-on value: $00
Depending on the PRG banking mode set via $5xx0, only the higher bits of this register are applied:
PRG A.. 21111111 09876543 -------- MMMMMMMM Submappers 1/3 in PRG Mode 0 (MMC3 2 MiB) or Extended MMC3 Mode BBMMMMMM Submappers 0/2/4 in PRG Mode 0 (MMC3 512 KiB) BBBMMMMM PRG Mode 1 (MMC3 256 KiB) BBBBMMMM PRG Mode 2 (MMC3 128 KiB) BBBBBBBC PRG Mode 3 (NROM-128) BBBBBBCC PRG Mode 4 (NROM-256) BBBBLLLC PRG Mode 5 (UNROM) M: Bit comes from MMC3 ($8000.6/7 or fixed bank) B: Bit comes from PRG Base Register ($5xx1) L: Bit comes from UNROM Latch ($8000-$FFFF or fixed bank) C: Bit comes from CPU
Submapper 5 only selects PRG A14-A18 (i.e. 512 KiB) via this register, selecting upper PRG bits via register $4800.
PRG Base Register MSB ($5xx5), Submapper 3 only
Mask: $Fxx7 (Submapper 3), x determined by solder pad setting
7654 3210 ---- ---- .... PPPP |||| ++++- PRG Base A24..A21 Power-on value: $00
PRG Base Register MSB ($4800), Submapper 5 only
Mask: $F800
7654 3210 ---- ---- ..PP PPPP || |||| ++-++++- PRG Base A24..A19 Power-on value: $00
CHR Base Register LSB ($5xx2)
Mask: $Fxx7 (Submapper 3), $5xx3 (all others), x determined by solder pad setting
7654 3210 ---- ---- ccdC CCCC |||| |||| ++++-++++- CHR A20..A13 ||+------- PRG A25 (Submapper 2 only) ++-------- PRG A24..A23 (Submapper 2 only) +--------- PRG A21 (Submapper 4) Power-on value: $00
Depending on the CHR banking mode set via $5xx0, only the higher bits of this register are applied:
CHR A.. 21111111111 09876543210 ----------- BBBMMMMMMMM MMC3 CHR Mode ($5xx0.6=0), 256 KiB ($5xx0.4=0) BBBBMMMMMMM MMC3 CHR Mode ($5xx0.6=0), 128 KiB ($5xx0.4=1) BBBBBBLLPPP CNROM CHR Mode ($5xx0.6=1, $5xx0.5=0), 32 KiB ($5xx0.4=0), Submapper 1 only BBBBBBBLPPP CNROM CHR Mode ($5xx0.6=1, $5xx0.5=0), 16 KiB ($5xx0.4=1), Submapper 1 only BBBBBBBBPPP NROM CHR Mode ($5xx0.6=1, $5xx0.5=1 or Submapper other than 1) M: Bit comes from MMC3 ($8000.0-5) B: Bit comes from CHR Base Register ($5xx2) L: Bit comes from CNROM Latch ($8000-$FFFF) P: Bit comes from PPU
CHR Base Register MSB ($5xx6), Submapper 3 only
Mask: $Fxx7 (Submapper 3), x determined by solder pad setting
7654 3210 ---- ---- .... PPPP |||| ++++- CHR Base A24..A21 Power-on value: $00
Extended Mode Register ($5xx3), Submappers 1-2 only
Mask: $Fxx3, x determined by solder pad setting
7654 3210 ---- ---- .?.. .?E. | +- Extended MMC3 Mode 0: disable 1: enable Power-on value: $00
Most multicarts write value $44 rather than $00 to disable Extended MMC3 Mode. Hardware tests do not indicate any difference in behavior between writing $00 and $44.
Mirroring Register ($A000)
Mask: $E003 7654 3210 ---- ---- .... ..MM ++- Select nametable mirroring 0: Vertical 1: Horizontal 2: Single-screen, page 0 (Submapper 2 only) 3: Single-screen, page 1 (Submapper 2 only) Power-on value: $00
Single-screen mirroring is only available when the RAM Configuration Register is enabled ($A001.5).
RAM Configuration Register ($A001), Submapper 2 only
Mask: $E003
This register functions like MMC3 register $A001 until bit 5 is set, which turns it into the RAM Configuration Register.
7654 3210 ---- ---- RFE. SCWW ||| |||| ||| ||++- Select 8 KiB PRG-RAM bank at $6000-$7FFF. Ignored if Bit 5 is clear. ||| |+--- Select the memory type in the first 8 KiB of CHR space. Ignored if Bit 5 is clear. ||| | 0: First 8 KiB are CHR-ROM ||| | 1: First 8 KiB are CHR-RAM ||| +---- Unknown ||+------- RAM Configuration Register Enable || 0: RAM Configuration Register disabled, $A001 functions as on MMC3, 8 KiB of WRAM || 1: RAM Configuration Register enabled, 32 KiB of WRAM |+-------- Outer Bank Registers Enable. Ignored if Bit 5 is clear. | 0: Outer Bank Registers disabled, $5000-$5FFF maps to the second 4 KiB of the 8 KiB WRAM bank 2 | 1: Outer Bank Registers enabled in the $5000-$5FFF range +--------- PRG RAM enable (0: disable, 1: enable) Power-on value: $00
UNROM latch ($8000-$FFFF)
In UNROM Mode (PRG Mode 5), writing to this address range changes the 16 KiB inner PRG bank at $8000-$BFFF.
CNROM latch ($8000-$FFFF), Submapper 1 only
In CNROM Mode, writing to this address range changes the inner CHR bank.
MMC3-compatible registers, Extended MMC3 Mode ($8000/$8001, $C000/$C001, $E000/$E001)
Mask: $E003 (verified on real hardware)
Some multicart games depend on writes to $9FFF not doing anything as a result of the MMC3 address mask being $E003 rather than the standard $E001.
If the "Extended MMC3 Mode" bit in register $5xx3 is clear, then these registers function identically to the MMC3. On Submappers 1 and 2, if the "Extended MMC3 Mode" bit is set, four more bank registers become available at $8000/$8001, so that the original two 2 KiB CHR banks become four 1 KiB CHR banks, and the two fixed 8 KiB PRG banks become selectable, similar to the RAMBO-1. Register $8000 if $5xx3 bit 1 is set:
7 bit 0 ---- ---- CP.. RRRR || |||| || ++++- Specify which bank register to update on next write to Bank Data register || $0: Select 1 KB CHR bank at PPU $0000-$03FF (or $1000-$13FF) || $1: Select 1 KB CHR bank at PPU $0800-$0BFF (or $1800-$1BFF) || $2: Select 1 KB CHR bank at PPU $1000-$13FF (or $0000-$03FF) || $3: Select 1 KB CHR bank at PPU $1400-$17FF (or $0400-$07FF) || $4: Select 1 KB CHR bank at PPU $1800-$1BFF (or $0800-$0BFF) || $5: Select 1 KB CHR bank at PPU $1C00-$1FFF (or $0C00-$0FFF) || $6: Select 8 KB PRG ROM bank at $8000-$9FFF (or $C000-$DFFF) || $7: Select 8 KB PRG ROM bank at $A000-$BFFF || $8: Select 8 KB PRG ROM bank at $C000-$DFFF (or $8000-$9FFF) || $9: Select 8 KB PRG ROM bank at $E000-$FFFF || $A: Select 1 KB CHR bank at PPU $0400-$07FF (or $1400-$17FF) || $B: Select 1 KB CHR bank at PPU $0C00-$0FFF (or $1C00-$1FFF) |+-------- Invert PRG A14 +--------- Invert CHR A12 Power-on values: * Standard MMC3 Registers $0-$7: $00, $02, $04, $05, $06, $07, $00, $01 * Extended MMC3 Registers $8-$B: $FE, $FF, $FF, $FF
Solder Pad
The address mask in the $5000-$5FFF range is determined by the solder pad setting:
Pad setting Address mask ----------- ------------ 0 $5013 1 $5023 2 $5043 3 $5083 4 $5103 5 $5203 6 $5403 7 $5803
- A solder pad setting of zero (address mask $5013) will produce a usable result for any ROM image.
- Some multicarts only display their menu at settings other than 0.
Protection (Submapper 2 only)
Later Waixing games (and re-releases of earlier games) use the RAM Configuration Register for copy-protection purposes:
- Write $A1 to $A001: Address range $5000-$5FFF to second half of 8 KiB WRAM bank 2, mapper registers there are disabled.
- Write three values to $5000, $5010 and $5013.
- Do further initialization.
- Write $E2 to $A001. Mapper registers in address range $5000-$5FFF; WRAM at CPU $6000-$7FFF points to 8 KiB WRAM bank 2.
- Copy 20 bytes from $7000 to $6000.
- Copy and XOR bytes from $6000, $6010 and $6013 to $0100-$0102.
- Execute code at CPU $0100.
Hacked ROMs can be detected by them writing to $5000/$5010/$5013 but then no longer jumping to $0100.
See also
- NES 2.0 Mapper 523 is a variant of this mapper with hard-wired mirroring that connects CHR-ROM differently to produce 4/2 KiB instead of 2/1 KiB banks.