4 ms·
The Apple ][ hardware did not have a direct way to track vertical blanking. There were hacks that used artifacts in the dynamic memory refresh to sniff out whe
by joezydeco 6y ago
The Apple ][ hardware did not have a direct way to track vertical blanking. There were hacks that used artifacts in the dynamic memory refresh to sniff out when the VBI was happening.
http://www.deater.net/weave/vmwprod/megademo/vapor_lock.html http://www.deater.net/weave/vmwprod/megademo/vapor_lock.html
- jonahbenton 6y agoAh, thank you, that's interesting. I don't recall puzzling through that exact machinery. But I had a IIe, not a II, and looking at resources for that- yeah, I had a rev B motherboard, and remember well working in the double hi res context, both black and white and color: http://www.battlestations.zone/2017/04/apple-ii-double-hi-res-from-ground-up.html http://www.battlestations.zone/2017/04/apple-ii-double-hi-re... So cool.