INES Mapper 040: Difference between revisions
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Like mapper 50, this hardware produces an interrupt 4096 M2 cycles after the IRQ is enabled. | Like mapper 50, this hardware produces an interrupt 4096 M2 cycles after the IRQ is enabled. | ||
The corresponding hardware is a [ | The corresponding hardware is a [//forums.nesdev.org/viewtopic.php?p=217200#p217200 CD4020 functioning as a 13-bit counter], and if the software doesn't acknowledge the interrupt for another 4096 cycles it will self-acknowledge. | ||
== See also == | == See also == | ||
* [http://nesdev.org/40.txt SMB2j aka "The Lost Levels" Mapper #40 Info] by The Mad Dumper. | * [http://nesdev.org/40.txt SMB2j aka "The Lost Levels" Mapper #40 Info] by The Mad Dumper. | ||
Revision as of 21:59, 21 April 2018
iNES Mapper 040 describes yet another pirate port of SMB2j from the FDS to a cartridge. It is very similar to mapper 50.
This description was produced from the source code of FCEUX and Nestopia.
Registers:
---------------------------
Range,Mask: $8000-FFFF, $E000
$8000: Disable and acknowledge IRQ
$A000: Enable IRQ
$E000: 8 KiB bank mapped at $C000
PRG Setup:
---------------------------
$6000 $8000 $A000 $C000 $E000
+-------+-------+-------+-------+-------+
| { 6 } | { 4 } | { 5 } | $E000 | { 7 } |
+-------+-------+-------+-------+-------+
Like mapper 50, this hardware produces an interrupt 4096 M2 cycles after the IRQ is enabled.
The corresponding hardware is a CD4020 functioning as a 13-bit counter, and if the software doesn't acknowledge the interrupt for another 4096 cycles it will self-acknowledge.
See also
- SMB2j aka "The Lost Levels" Mapper #40 Info by The Mad Dumper.
