Does $4200 have to only be written to once?

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psycopathicteen
Posts: 3140
Joined: Wed May 19, 2010 6:12 pm

Does $4200 have to only be written to once?

Post by psycopathicteen »

I know $4210 has to be read once per frame to stop NMI, but does that reset $4200?
Pokun
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Joined: Tue May 28, 2013 5:49 am
Location: Hokkaido, Japan

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

Post by Pokun »

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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