NES 2.0 Mapper 380

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Revision as of 19:31, 19 November 2021 by NewRisingSun (talk | contribs) (Rewrite to follow mapper 227's format, add UOROM mode)
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NES 2.0 Mapper 380 denotes the 970630C (submapper 0) and KN-35A (submapper 1) multicart circuit board mounting 256-512 KiB of PRG-ROM plus 8 KiB of unbanked CHR-RAM.

Address Latch ($8000-$FFFF, write)

[A~1... ..Om CRQP PpMS]
          || |||| |||+-0: PRG A14=p
          || |||| |||  1: PRG A14=CPU A14
          || |||| ||+- 0: Vertical mirroring
          || |||| ||   1: Horizontal mirroring
          || |+++-++-- PRG A18..A14
          || +-------- 0: CHR-RAM writeable
          ||           1: CHR-RAM write-protected
          |+---------- Submapper 0:
          |            0: PRG A3..A0=CPU A3..A0
          |            1: PRG A3..A0=Solder pad 3-0
          |            Submapper 1:
          |            0: PRG A17=Q if CPU A14=1
          |            1: PRG A17=1 if CPU A14=1 (UOROM)
          +----------- 0: When CPU A14=1: PRG A16..14=111 (UNROM)
                       1: When CPU A14=1: PRG A16..14=PPp
Power-on value: 0

Effective meaning:

Bit 9   Bit 8   Bit 0   Meaning
$200s   $100s   $001s
 (O)     (m)     (S)
  0       0       0     Switchable inner 16 KiB bank PPp at CPU $8000-$BFFF, fixed inner bank #7 at CPU $C000-$FFFF (UNROM)
  0       0       1     Switchable inner 16 KIB bank PP0 at CPU $8000-$BFFF, fixed inner bank #7 at CPU $C000-$FFFF (UNROM with only even banks reachable, pointless)
  0       1       0     Switchable inner 16 KiB bank QPPp at CPU $8000-$BFFF, fixed inner bank #15 at CPU $C000-$FFFF (UOROM, submapper 1 only)
  0       1       1     Switchable inner 16 KIB bank QPP0 at CPU $8000-$BFFF, fixed inner bank #15 at CPU $C000-$FFFF (UOROM with only even banks reachable, pointless, submapper 1 only)
  1       ?       0     Switchable 16 KiB inner bank PPp at CPU $8000-$BFFF, mirrored at CPU $C000-$FFFF (NROM-128)
  1       ?       1     Switchable 32 KiB inner bank PP at CPU $8000-$FFFF (NROM-256)
  • When the m bit is set, PRG A3-A0 are replaced with the values of four solder pads, which when the menu code reads particular ROM locations effectively selects one of up to 16 menus with different game counts (submapper 0 only).
  • Because all bits are cleared on reset, CPU $8000-$BFFF is set to 16 KiB bank #0, and $C000-$FFFF is set to 16 KiB bank #7 on reset.