INES Mapper 087: Difference between revisions
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m (cross-reference to m101 and CNROM. use "H" and "L" instead of "A" and "B" in disch's notes) |
(Suggestion for new development) |
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[[iNES Mapper 101]] is the same but with the bits in order. [[CNROM]] (which postdates mapper 87) is the same but with the bits in order and bus conflicts. | [[iNES Mapper 101]] is the same but with the bits in order. [[CNROM]] (which postdates mapper 87) is the same but with the bits in order and bus conflicts. | ||
New development should use mapper 101; those who wish to use a mapper 87 donor board can swap banks 1 and 2 of the CHR ROM. | |||
Revision as of 22:47, 16 August 2013
Here are Disch's original notes:
========================
= Mapper 087 =
========================
Example Games:
--------------------------
Argus (J)
City Connection (J)
Ninja Jajamaru Kun
Notes:
---------------------------
Regs are at $6000-7FFF, so these games have no SRAM.
Registers:
--------------------------
$6000-7FFF: [.... ..LH]
H = High CHR Bit
L = Low CHR Bit
This reg selects 8k CHR @ $0000. Note the reversed bit orders. Most games using this mapper only have 16k
CHR, so the 'H' bit is usually unused.
iNES Mapper 101 is the same but with the bits in order. CNROM (which postdates mapper 87) is the same but with the bits in order and bus conflicts. New development should use mapper 101; those who wish to use a mapper 87 donor board can swap banks 1 and 2 of the CHR ROM.
