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Author Topic: CHR bank switching at Mapper 4 (MMC3)  (Read 3770 times)


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CHR bank switching at Mapper 4 (MMC3)
« on: June 21, 2011, 11:57:28 am »
How can I change the progress so that the game loads another CHR bank? Is it possible to use breakpoint to find the progress or what?
Can someone explain me how to use this information :


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Re: CHR bank switching at Mapper 4 (MMC3)
« Reply #1 on: June 21, 2011, 01:23:14 pm »
MMC3 has 6 switchable CHR banks.  4 of them are 1k (64 tiles) in size, 2 of them are 2k (128 tiles) in size.  It can pick which side (left or right) gets the 2k banks, and which side gets the 1k banks.

Set a data breakpoint at $8000 and $8001
Watch for the command number you're interested in at $8000, probably command 0-5.
Watch for the bank number the game uses at $8001 after you hit the $8000 write you're interested in
Look at the game code, see if it just some something simple like LDA #$12 \ STA $8001.
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