INES Mapper 227: Difference between revisions
From NESdev Wiki
Jump to navigationJump to search
Rainwarrior (talk | contribs) m (iNES category sorting) |
m (m227-little note on emulator support) |
||
Line 1: | Line 1: | ||
[[Category:iNES Mappers|227]][[Category:Multicart mappers|227]] | [[Category:iNES Mappers|227]][[Category:Multicart mappers|227]] | ||
The Chinese unlicensed game <i>[NJXXX] Xiang Shuai Chuan Qi</i> will fail to load pattern data if the below notes on write protection are employed. Is this feature only on some 227 carts (more likely multicarts)? The write protection has been temporarily disabled in fceux and bizhawk until more evidence is gathered. It should be noted that VirtuaNES doesn't use the write protection. | The Chinese unlicensed game <i>[NJXXX] Xiang Shuai Chuan Qi</i> will fail to load pattern data if the below notes on write protection are employed. Is this feature only on some 227 carts (more likely multicarts)? The write protection has been temporarily disabled in fceux and bizhawk until more evidence is gathered. It should be noted that VirtuaNES doesn't use the write protection. | ||
In r2750 of fceux this support was rewritten; it should still work. It supposedly works in nestopia as well. | |||
Here are Disch's original notes: | Here are Disch's original notes: |
Revision as of 05:55, 30 November 2012
The Chinese unlicensed game [NJXXX] Xiang Shuai Chuan Qi will fail to load pattern data if the below notes on write protection are employed. Is this feature only on some 227 carts (more likely multicarts)? The write protection has been temporarily disabled in fceux and bizhawk until more evidence is gathered. It should be noted that VirtuaNES doesn't use the write protection.
In r2750 of fceux this support was rewritten; it should still work. It supposedly works in nestopia as well.
Here are Disch's original notes: ======================== = Mapper 227 = ======================== Example Game: -------------------------- 1200-in-1 Notes: --------------------------- This mapper has 8k CHR-RAM, and also has the ability to write protect it's CHR-RAM! Registers: --------------------------- $8000-FFFF: A~[.... ..LP OPPP PPMS] L = Last PRG Page Mode P = PRG Reg O = Mode M = Mirroring (0=Vert, 1=Horz) S = PRG Size Setup: --------------------------- When 'O' is set, CHR-RAM is write protected (writes have no effect). 'O' also changes the PRG mode. Note there is funky ANDs and ORs going on below depending on the modes: $8000 $A000 $C000 $E000 +---------------+---------------+ O=1, S=0: | P | P | +-------------------------------+ O=1, S=1: | < P > | +-------------------------------+ O=0, S=0, L=0: | P | P AND $38 | +---------------+---------------+ O=0, S=1, L=0: | P AND $3E | P AND $38 | +---------------+---------------+ O=0, S=0, L=1: | P | P OR $07 | +---------------+---------------+ O=0, S=1, L=1: | P AND $3E | P OR $07 | +---------------+---------------+