Talk:Programming UNROM

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Revision as of 05:19, 27 February 2013 by Tepples (talk | contribs) (What's ambiguous about mapper 2?)
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NES 2.0 advocacy

Converting a ROM from original iNES to NES 2.0 isn't strictly necessary unless the mapper is ≥ 256 or the iNES header is ambiguous. For example:

  • Several VRC mappers are ambiguous as to which low CPU address lines are connected to the mapper's port select.
  • Mapper 1 is ambiguous between SIROM (PRG A14 from MMC1 output) and other SxROM boards using 32K PRG (PRG A14 from CPU A14).
  • Mappers 1, 4, and 5 are ambiguous among PRG RAM sizes. For example, SNROM vs. SOROM, MMC3 vs. MMC6.
  • A few games (notably Low G Man) require the PRG RAM to be absent.

What's ambiguous about mappers 2 (UxROM), 3 (CNROM), and 7 (AOROM), other than whether or not the ROM has a positive chip enable to avoid bus conflicts? --Tepples (talk) 22:19, 26 February 2013 (MST)

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