INES Mapper 185: Difference between revisions
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m (refile, add cats:dlm & nescartdb. And this board definitely will have bus conflicts.) |
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[[Category:iNES Mappers]] | [[Category:iNES Mappers|185]][[Category:in NesCartDB|185]][[Category:Discrete logic mappers|185]] | ||
Here are Disch's original notes: | Here are Disch's original notes: | ||
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Registers: | Registers: (**BUS CONFLICTS**) | ||
--------------------------- | --------------------------- | ||
$8000-FFFF: [CCCC CCCC] | $8000-FFFF: [CCCC CCCC] | ||
CHR Reg | CHR Reg | ||
Revision as of 18:31, 29 July 2012
Here are Disch's original notes:
========================
= Mapper 185 =
========================
Example Games:
--------------------------
Spy Vs. Spy (J)
Mighty Bomb Jack (J)
Registers: (**BUS CONFLICTS**)
---------------------------
$8000-FFFF: [CCCC CCCC]
CHR Reg
Notes:
---------------------------
This mapper is retarded. These games only have 8k of CHR, but they seem to attempt to disable CHR by writing
a specific value to the CHR Reg, then they VERIFY that garbage is read back, then they swap back to the
actual CHR. If they don't get the expected garbage, they lock up.
Perhaps this was some sort of copy protection?
Each game has their own value that enables/disables CHR. Rather than failing to attempt to list all the
exact values used here (I don't know what all of them are), I can provide some logic:
if C AND $0F is nonzero, and if C does not equal $13: CHR is enabled
otherwise CHR is disabled
When CHR is disabled, it is as if CHR is filled with all $12's
