INES Mapper 144: Difference between revisions
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[[iNES Mapper 144]], allocated for the game ''Death Race'', describes a intentionally defective variant of the [[Color Dreams]] board ([[iNES Mapper 011|11]]). | [[iNES Mapper 144]], allocated for the game ''Death Race'', describes a intentionally defective variant of the [[Color Dreams]] board ([[iNES Mapper 011|11]]). | ||
This game's PCB (labelled '''50282''') is almost identical to the revision B Color Dreams boards, but | This game's PCB (labelled '''50282''') is almost identical to the revision B Color Dreams boards, but a 300Ω resistor was added between CPU D0 and the combination of mapper hardware and ROM. This addition means that ''only'' the ROM's ''least significant bit'' always wins bus conflicts. | ||
Nestopia-1.4.0 implements this as | Nestopia-1.4.0 implements this as <code>EffectiveData = (WrittenData & ROM[address]) | (ROM[address] & 1)</code> | ||
FCEUX-2.1.5 works around this by ignoring writes to 0x8000 | FCEUX-2.1.5 works around this by ignoring writes to 0x8000 | ||
The most succinct description is | The most succinct description is <code>EffectiveData = (ROM[address] & (WrittenData|1))</code> | ||
Revision as of 01:19, 26 October 2012
iNES Mapper 144, allocated for the game Death Race, describes a intentionally defective variant of the Color Dreams board (11).
This game's PCB (labelled 50282) is almost identical to the revision B Color Dreams boards, but a 300Ω resistor was added between CPU D0 and the combination of mapper hardware and ROM. This addition means that only the ROM's least significant bit always wins bus conflicts.
Nestopia-1.4.0 implements this as EffectiveData = (WrittenData & ROM[address]) | (ROM[address] & 1)
FCEUX-2.1.5 works around this by ignoring writes to 0x8000
The most succinct description is EffectiveData = (ROM[address] & (WrittenData|1))
