INES Mapper 185: Difference between revisions

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[[Category:iNES Mappers]]
[[Category:iNES Mappers]]
   Here are Disch's original notes:
   Here are Disch's original notes:
========================
 
=  Mapper 185          =
  ========================
========================
  =  Mapper 185          =
 
  ========================
 
 
Example Games:
 
--------------------------
  Example Games:
Spy Vs. Spy (J)
  --------------------------
Mighty Bomb Jack (J)
  Spy Vs. Spy (J)
 
  Mighty Bomb Jack (J)
 
 
Registers:
 
---------------------------
  Registers:
I'm unsure whether or not this mapper suffers from bus conflicts.  I believe it does!  Use extreme caution!
  ---------------------------
 
  I'm unsure whether or not this mapper suffers from bus conflicts.  I believe it does!  Use extreme caution!
  $8000-FFFF:  [CCCC CCCC]
 
    CHR Reg
    $8000-FFFF:  [CCCC CCCC]
 
      CHR Reg
 
 
Notes:
 
---------------------------
  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
  This mapper is retarded.  These games only have 8k of CHR, but they seem to attempt to disable CHR by writing
actual CHR.  If they don't get the expected garbage, they lock up.
  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?
 
 
  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:
  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
  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
 
  When CHR is disabled, it is as if CHR is filled with all $12's

Revision as of 23:51, 13 November 2011

 Here are Disch's original notes:
 
 ========================
 =  Mapper 185          =
 ========================
 
 
 Example Games:
 --------------------------
 Spy Vs. Spy (J)
 Mighty Bomb Jack (J)
 
 
 Registers:
 ---------------------------
 I'm unsure whether or not this mapper suffers from bus conflicts.  I believe it does!  Use extreme caution!
 
   $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