NES 2.0 Mapper 344: Difference between revisions
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NewRisingSun (talk | contribs) (Describe known solder pads. Have to think about how to apply this to submappers given that only some combinations make sense.) |
NewRisingSun (talk | contribs) (Take NC7000M out of mapper 344, as 344 does quite a few things differently after all.) |
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{{DEFAULTSORT:344}}[[Category:Multicart mappers]][[Category:MMC3-like mappers]][[Category:Mappers with scanline IRQs]] | {{DEFAULTSORT:344}}[[Category:Multicart mappers]][[Category:MMC3-like mappers]][[Category:Mappers with scanline IRQs]] | ||
'''NES 2.0 Mapper 344''' denotes the '''GN-26''' | '''NES 2.0 Mapper 344''' denotes the '''GN-26''' [[MMC3]]-based multicart circuit board. Its UNIF board name is '''BMC-GN-26''' (with incorrect PRG bank order). | ||
* ''快打金卡终极挑战 (Kuàidǎ Jīnkǎ Zhōngjí Tiǎozhàn) 3/6-in-1'' | * ''快打金卡终极挑战 (Kuàidǎ Jīnkǎ Zhōngjí Tiǎozhàn) 3/6-in-1'' | ||
==Outer Bank and Mode Register ($6000-$7FFF, write)== | ==Outer Bank and Mode Register ($6000-$7FFF, write)== | ||
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A~FEDC BA98 7654 3210 | A~FEDC BA98 7654 3210 | ||
------------------- | ------------------- | ||
.... .... . | 011. .... .... SMBA | ||
||++- PRG/CHR A18..17 | |||
|+--- Select PRG-ROM mode and CHR A17 mode | |||
| 0: MMC3 PRG mode, CHR A17=$6000.0 | |||
| 1: NROM PRG mode, CHR A17=MMC3 A17 | |||
+---- Solder pad test | |||
* WRAM must be enabled in $A001.7 before writing to this register. | * WRAM must be enabled in $A001.7 before writing to this register. | ||
* The inner PRG bank is restricted to 128 KiB. | * The inner PRG bank is restricted to 128 KiB. | ||
* NROM mode forces MMC3's CPU A13 and A14 inputs to GND and replaces MMC3's PRG A13 output with CPU A13. This means that MMC3 bank register 6 bits 1-3 | * NROM mode PRG forces MMC3's CPU A13 and A14 inputs to GND and replaces MMC3's PRG A13 output with CPU A13. This means that MMC3 bank register 6 bits 1-3 provide PRG A14..A16 for the entire CPU $8000-$FFFF range. | ||
* The common dump of ''快打金卡终极挑战 (Kuàidǎ Jīnkǎ Zhōngjí Tiǎozhàn) 3/6-in-1'' has the 128 KiB PRG-ROM banks mixed-up, correct would be in the order 0, 3, 1, 2. | * The common dump of ''快打金卡终极挑战 (Kuàidǎ Jīnkǎ Zhōngjí Tiǎozhàn) 3/6-in-1'' has the 128 KiB PRG-ROM banks mixed-up, correct would be in the order 0, 3, 1, 2. | ||
* Depending on whether a solder pad is connected, setting the S bit may disable PRG-ROM. The menu sets this bit to select between two different game counts. | |||
==MMC3-compatible registers== | ==MMC3-compatible registers== | ||
Mask: $E001 | Mask: $E001 | ||
See [[MMC3]]. | See [[MMC3]]. | ||
Revision as of 16:37, 25 May 2021
NES 2.0 Mapper 344 denotes the GN-26 MMC3-based multicart circuit board. Its UNIF board name is BMC-GN-26 (with incorrect PRG bank order).
- 快打金卡终极挑战 (Kuàidǎ Jīnkǎ Zhōngjí Tiǎozhàn) 3/6-in-1
Outer Bank and Mode Register ($6000-$7FFF, write)
Mask: $E000
A~FEDC BA98 7654 3210
-------------------
011. .... .... SMBA
||++- PRG/CHR A18..17
|+--- Select PRG-ROM mode and CHR A17 mode
| 0: MMC3 PRG mode, CHR A17=$6000.0
| 1: NROM PRG mode, CHR A17=MMC3 A17
+---- Solder pad test
- WRAM must be enabled in $A001.7 before writing to this register.
- The inner PRG bank is restricted to 128 KiB.
- NROM mode PRG forces MMC3's CPU A13 and A14 inputs to GND and replaces MMC3's PRG A13 output with CPU A13. This means that MMC3 bank register 6 bits 1-3 provide PRG A14..A16 for the entire CPU $8000-$FFFF range.
- The common dump of 快打金卡终极挑战 (Kuàidǎ Jīnkǎ Zhōngjí Tiǎozhàn) 3/6-in-1 has the 128 KiB PRG-ROM banks mixed-up, correct would be in the order 0, 3, 1, 2.
- Depending on whether a solder pad is connected, setting the S bit may disable PRG-ROM. The menu sets this bit to select between two different game counts.
MMC3-compatible registers
Mask: $E001
See MMC3.
