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Does $4200 have to only be written to once?

Posted: Sat Sep 09, 2017 2:18 pm
by psycopathicteen
I know $4210 has to be read once per frame to stop NMI, but does that reset $4200?

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

Posted: Tue Sep 12, 2017 3:36 am
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.