4-in-1 multicart (UNROM/ANROM): Difference between revisions
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[[File:4-in-1 unrom,anrom top.jpg|thumb|Top layer]] [[File:4-in-1 unrom,anrom bottom.jpg|thumb|Bottom layer]] [[File:4-in-1 unrom,anrom schematics.png|thumb|Schematics]] | [[File:4-in-1 unrom,anrom top.jpg|thumb|Top layer]] [[File:4-in-1 unrom,anrom bottom.jpg|thumb|Bottom layer]] [[File:4-in-1 unrom,anrom schematics.png|thumb|Schematics]] | ||
[[Category:Mappers]] | |||
Latest revision as of 03:43, 6 October 2022
PRG: 512 kiB ROM
CHR: 8 kiB RAM
Bus conflicts: no
gG | GAME ---+---------------- 00 | Trog 10 | Duck Tales I 01 | Marble Madness 11 | Captain Skyhawk
Registers
$6000-$7FFF: UNROM/ANROM banking type & game number
7 bit 0
---- ----
TgGP
||||
|||+------------ protection: 0 - off, 1 - contents of this register cannot be changed until console reset
|++------------- selects one of four 128 kB games; g is lower address line: PRG-A18 = G, PRG-A17=g
+--------------- banking style: 0 - UNROM: $8000-$bfff 16 kB switchable CBA bank, $c000-$ffff fixed to last bank, PPU vertical mirroring
1 - ANROM: $8000-$ffff 32 kB switchable BA bank, PPU single screen mirroring
$8000-$FFFF: bank select (when in UNROM mode)
7 bit 0
---- ----
CBA
|||
+++------------ UNROM bank (when in UNROM MODE)
$8000-$FFFF: bank select (when in ANROM mode)
7 bit 0 ---- ---- M BA | || | ++------------ ANROM bank (when in ANROM MODE) +----------------- one screen mirroring
