NES 2.0 Mapper 558: Difference between revisions
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All registers are initialized to $00 on reset. | All registers are initialized to $00 on reset. | ||
==PRG-ROM Bank Low ($5000, write)== | ==PRG-ROM Bank Low ($5000, write)== | ||
Mask: $ | Mask: $FF00 | ||
D~7654 3210 | D~7654 3210 | ||
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* Games with 1 MiB PRG-ROM that set $5300.0=1 still use bit 0 to denote PRG A19; they must connect both ASIC PRG A19 and A20 outputs to the ROM chip's A19 pin. | * Games with 1 MiB PRG-ROM that set $5300.0=1 still use bit 0 to denote PRG A19; they must connect both ASIC PRG A19 and A20 outputs to the ROM chip's A19 pin. | ||
==Microwire Interface ($5200, write)== | ==Microwire Interface ($5200, write)== | ||
Mask: $ | Mask: $FF00 | ||
D~7654 3210 | D~7654 3210 | ||
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* the choice of which latched bit to be output to the DAT and CLK pins changes; | * the choice of which latched bit to be output to the DAT and CLK pins changes; | ||
or in other words, the DAT and CLK pins swap their values until $5200 is written to again. | or in other words, the DAT and CLK pins swap their values until $5200 is written to again. | ||
==Mode ($5300, write)== | ==Mode ($5300, write)== | ||
Mask: $ | Mask: $FF00 | ||
D~7654 3210 | D~7654 3210 | ||
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* Writes to this register are ''not'' subject to D0/D1 bit-swapping, i.e. the register is not affected by its own bit 0. | * Writes to this register are ''not'' subject to D0/D1 bit-swapping, i.e. the register is not affected by its own bit 0. | ||
* Because this register is initialized to $00 on reset, thus clearing bit 2 which causes PRG A15/A16 to be held high, the game will boot in 32 KiB PRG-ROM bank #3. | * Because this register is initialized to $00 on reset, thus clearing bit 2 which causes PRG A15/A16 to be held high, the game will boot in 32 KiB PRG-ROM bank #3. | ||
==Microwire Interface ($5500, read)== | |||
Mask: $FF00 | |||
D~7654 3210 | |||
--------- | |||
.... .A.. | |||
| | |||
| | |||
+--- 93C66 EEPROM DAT input | |||
Unlike [[INES Mapper 164]], the EEPROM input is ''not'' inverted. | |||
=Notes= | =Notes= | ||
* Setting $5300.0=1 will effectively swap PRG A15/A16 and PRG A19/A20. Cartridges using this mapper must be dumped with $5300=$04 during dumping, even if the games run with $5300=$07. Otherwise, PRG A15/A16 and PRG A19/A20 would be swapped both during dumping and emulation, negating the effect; such images will therefore not work with an accurate emulation of this mapper. | * Setting $5300.0=1 will effectively swap PRG A15/A16 and PRG A19/A20. Cartridges using this mapper must be dumped with $5300=$04 during dumping, even if the games run with $5300=$07. Otherwise, PRG A15/A16 and PRG A19/A20 would be swapped both during dumping and emulation, negating the effect; such images will therefore not work with an accurate emulation of this mapper. |
Revision as of 16:30, 1 August 2020
NES 2.0 Mapper 558 denotes the 燕城 (Yànchéng) YC-03-09 circuit board, used for the following games:
- 口袋精靈: 水晶 (Pokémon: Crystal Edition)
- 大話三國 (Dàhuà Sānguó)
A compatible circuit board with an unknown PCB code is used for the original editions of a few games from 外星 (Wàixīng):
- Pet Family - 宠物大家族: 部落纷争 (ES-1081)
- Pet Evolve - 宠物进化史 (ES-1085)
- 口袋妖怪꞉ 鑽石版 (Pokémon: Diamond Edition, ES-1090)
- 口袋精靈: 紅 and its title screen hack 宠物: 红 (Pokémon: Red Edition, ES-1088)
- 富甲三国 (Fùjiǎ Sānguó)
- 数码暴龙 4: 水晶版 and its title screen hack 数码宝贝 (Digimon 4: Crystal Edition)
- 盟军敢死队 - Commandos
The Yànchéng save the game state to a 93C66 512-byte serial EEPROM, while the Wàixīng games save to 8 KiB battery-backed WRAM. The NES 2.0 Header's PRG-NVRAM field distinguishes between the two board variants.
Banks
- CPU $6000-$7FFF: up to 8 KiB unbanked PRG-RAM, can be battery-backed
- CPU $8000-$FFFF: 32 KiB switchable PRG-ROM bank
- PPU $0000-$1FFF: 8 KiB unbanked CHR-RAM bank
- Nametable mirroring: hard-wired
Registers
All registers are initialized to $00 on reset.
PRG-ROM Bank Low ($5000, write)
Mask: $FF00 D~7654 3210 --------- .... PPPP ++++- PRG A18..A15
- Note that if $5300.0 is 1, the two lowest bits are swapped during writing.
- Changing the value of $5300.0 without writing to $5000 afterwards does not change the latched bits.
PRG-ROM Bank High ($5100, write)
Mask: $FB00 D~7654 3210 --------- .... ..PP ++- PRG A20..A19
- Note that if $5300.0 is 1, the two lowest bits are swapped during writing.
- Games with 1 MiB PRG-ROM that set $5300.0=1 still use bit 0 to denote PRG A19; they must connect both ASIC PRG A19 and A20 outputs to the ROM chip's A19 pin.
Microwire Interface ($5200, write)
Mask: $FF00 D~7654 3210 --------- .... .SCD ||+- 93C66 EEPROM DAT ($5300.0=0)/CLK($5300.0=1) output |+-- 93C66 EEPROM CLK ($5300.0=0)/DAT($5300.0=1) output +--- 93C66 EEPROM CS output
Note that if $5300.0 is 1, there are two effects on this register:
- the two lowest bits are swapped during writing before being latched;
- the two latched bits are swapped before being output as long as $5300.0 remains 1.
These two effects counteract each other, so that register $5200 effectively operates identically regardless of the $5300.0 value. When writing to $5300 and changing its bit 0 without writing to $5200 afterwards, ...
- the latched values of B and C remain as when they were written, but
- the choice of which latched bit to be output to the DAT and CLK pins changes;
or in other words, the DAT and CLK pins swap their values until $5200 is written to again.
Mode ($5300, write)
Mask: $FF00 D~7654 3210 --------- .... .A?B | +- 0: Leave D0,D1 unmodified on register writes to $5000-$5200. | 1: Swap D0,D1 on all register writes to $5000-$5200. +--- 0: PRG A15/A16=1 1: PRG A15/A16 from $5000
- Writes to this register are not subject to D0/D1 bit-swapping, i.e. the register is not affected by its own bit 0.
- Because this register is initialized to $00 on reset, thus clearing bit 2 which causes PRG A15/A16 to be held high, the game will boot in 32 KiB PRG-ROM bank #3.
Microwire Interface ($5500, read)
Mask: $FF00 D~7654 3210 --------- .... .A.. | | +--- 93C66 EEPROM DAT input
Unlike INES Mapper 164, the EEPROM input is not inverted.
Notes
- Setting $5300.0=1 will effectively swap PRG A15/A16 and PRG A19/A20. Cartridges using this mapper must be dumped with $5300=$04 during dumping, even if the games run with $5300=$07. Otherwise, PRG A15/A16 and PRG A19/A20 would be swapped both during dumping and emulation, negating the effect; such images will therefore not work with an accurate emulation of this mapper.
Note
The Wàixīng games using this mapper were previously set to 162/163 or 164, resulting in incompatibility either because of the different address of the PRG-ROM Bank High register (mapper 162/163) or the different startup bank (164).
See also
- INES Mapper 162/163 swap the meaning of registers $5100 and $5200, and use the microwire interface only for protection purposes.
- INES Mapper 164 is an earlier implementation without D0/D1 swapping, optional UNROM-like bankswitching, and a 1 bpp CHR mode.