NES 2.0 Mapper 439: Difference between revisions
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==Latch Register ($8000-$FFFF, write)== | ==Latch Register ($8000-$FFFF, write)== | ||
D~[M..PP PPPP] | D~[M..PP PPPP] Address mask: $8000 | ||
| ++-++++- PRG A19..A14 when CPU A14=0, | | ++-++++- PRG A19..A14 when CPU A14=0, | ||
| $3F when CPU A14=1 | | $3F when CPU A14=1 | ||
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==Outer Bank Register ($6000, write)== | ==Outer Bank Register ($6000, write)== | ||
D~[.PPP ....] | D~[.PPP ....] Address mask: $E001 | ||
+++------ PRG A19..A17 if enabled via $6001 | +++------ PRG A19..A17 if enabled via $6001 | ||
==Mask Register ($6001, write)== | ==Mask Register ($6001, write)== | ||
D | D~[MPPP ....] Address mask: $E001 | ||
|||+------- 0: PRG A17 from Latch, 1: PRG A17 from $6000 | |||+------- 0: PRG A17 from Latch, 1: PRG A17 from $6000 | ||
||+-------- 0: PRG A18 from Latch, 1: PRG A18 from $6000 | ||+-------- 0: PRG A18 from Latch, 1: PRG A18 from $6000 | ||
|+--------- 0: PRG A19 from Latch, 1: PRG A19 from $6000 | |+--------- 0: PRG A19 from Latch, 1: PRG A19 from $6000 | ||
+---------- 1: Protect Mirroring bit in Latch from being changed | +---------- 1: Protect Mirroring bit in Latch from being changed | ||
Latest revision as of 19:25, 21 June 2023
NES 2.0 Mapper 439 denotes the YS2309 UxROM-like multicart PCB. Its UNIF MAPRs are BMC-DS-07 and BMC-K86B. All registers set to $00 on reset.
Latch Register ($8000-$FFFF, write)
D~[M..PP PPPP] Address mask: $8000 | ++-++++- PRG A19..A14 when CPU A14=0, | $3F when CPU A14=1 +---------- Nametable mirroring, 0=Vertical, 1=Horizontal
This is basically an UxROM-like latch register for up to 1 MiB of PRG ROM, plus software-switchable mirroring.
Outer Bank Register ($6000, write)
D~[.PPP ....] Address mask: $E001
+++------ PRG A19..A17 if enabled via $6001
Mask Register ($6001, write)
D~[MPPP ....] Address mask: $E001 |||+------- 0: PRG A17 from Latch, 1: PRG A17 from $6000 ||+-------- 0: PRG A18 from Latch, 1: PRG A18 from $6000 |+--------- 0: PRG A19 from Latch, 1: PRG A19 from $6000 +---------- 1: Protect Mirroring bit in Latch from being changed
