Does $4200 have to only be written to once?

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psycopathicteen
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Joined: Wed May 19, 2010 6:12 pm

Does $4200 have to only be written to once?

Post by psycopathicteen » Sat Sep 09, 2017 2:18 pm

I know $4210 has to be read once per frame to stop NMI, but does that reset $4200?

Pokun
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Location: Hokkaido, Japan

Re: Does $4200 have to only be written to once?

Post by Pokun » Tue Sep 12, 2017 3:36 am

I don't think so from reading Nintendo's dev docs. Reading $4210 acknowledges NMI and resets the NMI Flag (bit 7 of $4210), but NMIs are only enabled/disabled using bit 7 of $4200.

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