INES Mapper 250: Difference between revisions

Latest revision as of 20:10, 14 April 2023

INES Mapper 250 is a mapper by Nitra, used for pirate games such as Time Diver Avenger and the Queen Bee V.

Hardware consists of regular MMC3 chip connected in different way:

A10 instead of A0 is used to determine which register to write to (i.e. the registers are at $8000, $8400, $A000, $A400, $C000, $C400, $E000, $E400 and their associated
A7..A0 is used instead of D7..D0: the value written to each register is the lower byte of the address (i.e. address AND $00FF), data value is discarded

Queen Bee V contains also 74153 mux which controls PRG-A13 resulting in the following change:

below
$8000 $8000 $a000 $c000 $e000
   0   MMC3  MMC3   0     1

Source: [1]

@@ Line 2: / Line 2: @@
 [[INES Mapper 250]] is a mapper by Nitra, used for pirate games such as [[wikia:c:bootleggames:Time Diver: Avenger|Time Diver Avenger]] and the Queen Bee V.
-FCEUX implements mapper 250 as an MMC3 variant where instead of using the LSB of the address to determine which register to write to, it uses the $0400s bit (i.e. the registers are at $8000, $8400, $A000, $A400, $C000, $C400, $E000, $E400 and their associated mirrors).
+Hardware consists of regular MMC3 chip connected in different way:
+* A10 instead of A0 is used to determine which register to write to (i.e. the registers are at $8000, $8400, $A000, $A400, $C000, $C400, $E000, $E400 and their associated
+* A7..A0 is used instead of D7..D0: the value written to each register is the lower byte of the address (i.e. address AND $00FF), data value is discarded
-Per Nintendulator, the provided value to write is discarded.  Instead, the value written to each register is the lower byte of the address (i.e. address AND $00FF).
+* Queen Bee V contains also 74153 mux which controls PRG-A13 resulting in the following change:
+ below
+  $8000 $8000 $a000 $c000 $e000
+   MMC3  MMC3   0     1
+Source: [http://krzysiobal.com/carts/?action=search&mpr=250]