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From: mmphosis <mmphosis@macgui.com>
Newsgroups: comp.sys.apple2.programmer
Subject: Re: Vertical Blank on Apple ][+
Date: Thu, 23 Mar 2023 14:33:12 -0000 (UTC)
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Xref: csiph.com comp.sys.apple2.programmer:6023

> Does this work on both hi-res screens?

For HGR2, change the $2000 addresses to $4000 addresses and BIT $C055 before
the wait routine.

> And on a IIe with the $C019 soft switch, Instead of racing the beam (or
> staying ahead of the refresh), isn't it better to start drawing when the
> beam is finished refreshing and is at the bottom of the screen, about to
> go
> up, and start drawing to the screen then.  Doesn't this do the same thing
> but offers a little more time to draw to the screen before the screen gets
> updated on the next time around?

Timing is everything and is fraught with peril.

http://www.deater.net/weave/vmwprod/megademo/cycle_switching.html

https://rich12345.tripod.com/aiivideo/softalk.html

https://web.archive.org/web/20150706084550/http://hoop-la.ca/apple2/2015/winterwarmup/