INES Mapper 185: Difference between revisions
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'''iNES Mapper 185''' is used for games that use the [[CNROM]] board with weak copy protection measures. | '''iNES Mapper 185''' is used for games that use the [[CNROM]] board with weak copy protection measures. | ||
======================== | ======================== | ||
= Mapper 185 = | = Mapper 185 = | ||
======================== | ======================== | ||
Example Games: | Example Games: | ||
| Line 13: | Line 10: | ||
Spy Vs. Spy (J) | Spy Vs. Spy (J) | ||
Mighty Bomb Jack (J) | Mighty Bomb Jack (J) | ||
Registers: (**BUS CONFLICTS**) | Registers: (**BUS CONFLICTS**) | ||
--------------------------- | --------------------------- | ||
$8000-FFFF: [ | $8000-FFFF: [..CC ..CC] | ||
CHR Reg | CHR Reg | ||
| Line 23: | Line 19: | ||
Notes: | Notes: | ||
--------------------------- | --------------------------- | ||
This mapper is retarded. These games only have 8k of CHR, | This mapper is retarded. These games only have 8k of CHR, and they attempt to disable CHR by writing | ||
a specific value to the CHR Reg, then | a specific value to the CHR Reg, then 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. | actual CHR. If they don't get the expected garbage, they lock up. | ||
| Line 35: | Line 31: | ||
otherwise CHR is disabled | otherwise CHR is disabled | ||
When CHR is disabled, | When CHR is disabled, the pattern tables are open bus. Theoretically, this should | ||
return the LSB of the address read, but real-world behavior may vary. | |||
This table has been assembled from nocash and the sources of MESS, Nestopia, and FCEUX. | |||
{| class="datatable" | |||
! !! colspan=2|if this value is written | |||
|- | |||
! Game !! Must work !! Mustn't work <!-- possible submapper number --> | |||
|- | |||
| [http://bootgod.dyndns.org:7777/profile.php?id=1262 Bird Week] || 0x0F || 0xF0 <!-- 3 --> | |||
|- | |||
| [http://bootgod.dyndns.org:7777/profile.php?id=1264 B-Wings] || 0x33 || 0x00 <!-- F --> | |||
|- | |||
| [http://bootgod.dyndns.org:7777/profile.php?id=1261 Mighty Bomb Jack] || 0x11 || 0x00 <!-- 5 --> | |||
|- | |||
| Sansuu 1 Nen and [http://bootgod.dyndns.org:7777/profile.php?id=1263 Sansuu 2 Nen] || 0x22 || 0x20 <!-- A --> | |||
|- | |||
| [http://bootgod.dyndns.org:7777/profile.php?id=3791 Sansuu 3 Nen] || 0xFF || 0x00 <!-- F --> | |||
|- | |||
| [http://bootgod.dyndns.org:7777/profile.php?id=3592 Spy vs Spy] || 0x21 || 0x13 <!-- 9 --> | |||
|- | |||
| [http://bootgod.dyndns.org:7777/profile.php?id=2332 Seicross (v2)] || 0x20 || 0x21 <!-- 8 --> | |||
|} | |||
Revision as of 01:19, 18 January 2014
iNES Mapper 185 is used for games that use the CNROM board with weak copy protection measures.
========================
= Mapper 185 =
========================
Example Games:
--------------------------
Spy Vs. Spy (J)
Mighty Bomb Jack (J)
Registers: (**BUS CONFLICTS**)
---------------------------
$8000-FFFF: [..CC ..CC]
CHR Reg
Notes:
---------------------------
This mapper is retarded. These games only have 8k of CHR, and they attempt to disable CHR by writing
a specific value to the CHR Reg, then 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, the pattern tables are open bus. Theoretically, this should
return the LSB of the address read, but real-world behavior may vary.
This table has been assembled from nocash and the sources of MESS, Nestopia, and FCEUX.
| if this value is written | ||
|---|---|---|
| Game | Must work | Mustn't work |
| Bird Week | 0x0F | 0xF0 |
| B-Wings | 0x33 | 0x00 |
| Mighty Bomb Jack | 0x11 | 0x00 |
| Sansuu 1 Nen and Sansuu 2 Nen | 0x22 | 0x20 |
| Sansuu 3 Nen | 0xFF | 0x00 |
| Spy vs Spy | 0x21 | 0x13 |
| Seicross (v2) | 0x20 | 0x21 |
