INES Mapper 111: Difference between revisions

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{{DEFAULTSORT:111}}[[Category:iNES Mappers]][[Category:GNROM-like mappers]][[Category:Mappers using $4020-$5FFF]]
#REDIRECT [[GTROM]]
Mapper 111 is used by Memblers' Cheapocabra GT-ROM 512k self-flashable board.
 
It is only well-defined for 512KiB PRG, 32 KiB CHR-RAM, and 4-screen nametables.
 
Mask: $D000
$5000: [grnc pppp]
        |||| ||||
        |||| ++++- Select 32 KiB PRG at CPU $8000-$FFFF
        |||+------ Select 8 KiB CHR RAM at PPU $0000-$1FFF
        ||+------- Select 8 KiB nametable and scratch RAM at PPU $2000-$3EFF
        |+-------- 0: red LED is lit, 1: off
        +--------- 0: green LED is lit, 1: off
 
Like [[iNES Mapper 030]], the specific flash used on this board is the SST39SF040. Games are expected to use the chip's self-erase and self-write abilities for game saves.
 
The specific hardware on this board is a [[74377]], a [[7402]], and a [[7410]]. The exact connectivity is not known, but the functions evaluated by the logic must include:
* CHRRAMA14 = if (PPUA13==1) { n } else { c }
* PRGROM/OE = NOT(R/W)
* Latch on M2, /ROMSEL, A14, A12 high, and maybe on R/W low
 
Information: [http://forums.nesdev.org/viewtopic.php?p=146039 Membler Industries in 2015] - forum post describing the board.

Revision as of 03:32, 10 October 2017

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