NES 2.0 Mapper 328: Difference between revisions
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(more information about this oddball) |
(→Random number generator or Protection ($CE80-$CEFF, $FE80-$FEFF, read): 16K PRG means A14 is ignored...) |
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==Random number generator or Protection ($CE80-$CEFF, $FE80-$FEFF, read)== | ==Random number generator or Protection ($CE80-$CEFF, $FE80-$FEFF, read)== | ||
Mask: unknown. If what CaH4e3 wrote (quoted below) is accurate, $ | Mask: unknown. If what CaH4e3 wrote (quoted below) is accurate, $BFFF. | ||
D~7654 3210 | D~7654 3210 | ||
Revision as of 19:01, 1 June 2018
NES 2.0 mapper 328 is used for the Test Ver. 1.01 Dlya Proverki TV Pristavok test cartridge. Its UNIF board name is UNL-RT-01. There is only 16K of PRG and 2K of CHR and mirroring is hard-wired.
Random number generator or Protection ($CE80-$CEFF, $FE80-$FEFF, read)
Mask: unknown. If what CaH4e3 wrote (quoted below) is accurate, $BFFF.
D~7654 3210
---------
1111 RR1R
++-+- Random bits
It's not known whether the RRR bits are meant to be an actual random number or a protection that can be fooled by returning random numbers.
CaH4e3 wrote that the "PRG EPROM has copy protected areas with "weak bits", which is tested at some points of the program. [The random numbers are t]rying to simulate "weak bits" behaviour"
