NES 2.0 Mapper 548: Difference between revisions
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{{DEFAULTSORT: | {{DEFAULTSORT:548}}[[Category:FDS conversion mappers]][[Category:Mappers with fixed-timing cycle IRQs]][[Category:Mappers with CHR RAM]] | ||
'''NES 2.0 Mapper 548''' denotes 科統實業股份有限公司 (Co Tung Co.)'s '''CTC-15''' circuit board, used for their cartridge conversion of the FDS game ''Almanaの奇跡 (Almana no Kiseki)''. | '''NES 2.0 Mapper 548''' denotes 科統實業股份有限公司 (Co Tung Co.)'s '''CTC-15''' circuit board, used for their cartridge conversion of the FDS game ''Almanaの奇跡 (Almana no Kiseki)''. | ||
=Banks= | =Banks= | ||
Revision as of 18:18, 9 October 2019
NES 2.0 Mapper 548 denotes 科統實業股份有限公司 (Co Tung Co.)'s CTC-15 circuit board, used for their cartridge conversion of the FDS game Almanaの奇跡 (Almana no Kiseki).
Banks
- CPU $6000-$7FFF: 8 KiB unbanked PRG-RAM
- CPU $8000-$BFFF: Switchable 16 KiB PRG-ROM bank
- CPU $C000-$FFFF: Fixed 16 KiB PRG-ROM bank #3
- PPU $0000-$1FFF: 8 KiB unbanked CHR-RAM
Mirroring is hard-wired to Horizontal.
Registers
Latch and IRQ control ($4800, write)
Mask: $F800
A~FEDC BA98 7654 3210
-------------------
0100 1... ..A. BC..
+--++--- Latch value
+--- IRQ control
Power-on value (ABC): $7
- The latch value is not used until the Latch Apply register is writtent o.
- IRQ control:
- 0: Enable M2 counting and IRQ generation
- 1: Disable M2 counting and IRQ generation, acknowledge IRQ.
If counting is enabled, the counter is clocked on every falling edge of M2. An IRQ is generated at a counter value of 23680 and self-acknowledged at a value of 24320.
Latch Apply ($5000, write)
Mask: $F800
Upon writing to the $5000-$57FF address range, the latched value written to $4800 is XOR'd with $05 and applied as the 16 KiB PRG-ROM bank at CPU $8000-$BFFF. The power-on bank is $7.
