Posted By
siz
on 2020-10-26
10:39:23
|  Re: Looking for collaborator
That's right. But I strongly advise against setting that bit as that can cause problems because the video clock crystal (and the KERNAL ROM) is different in the PAL and NTSC machines.
The proper way of handling PAL and NTSC is to keep that bit untouched:
lda $ff07
and #$40
ora #yourvalue
sta $ff07
Or save the value at initialization time:
lda $ff07
and #$40
sta palntscflag
...
and when you want to write $ff07
lda #yourvalue
ora palntscflag
sta $ff07
There are some edge cases (a bit faster CPU clock) when you can set this bit intentionally but in that case you won't have picture.
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