Thomas wrote:
(1) I'm vaguely aware that there's a "current scanline" hardware
counter somewhere - does that count actual PAL lines or only lines
with pixels on them?
HPEN port (&01f8) will give the current scanline - for scanlines in the
display area only (0-191 iirc)
And how long does the end-of-display interrupt signal last? My memory
is saying 24 cycles, but I'm not sure why. I guess since we're on a
system with no explicit interrupt acknowledgments, it's going to be
something tiny?
If I also remember correctly from all the tinkering I've done, the interrupt
pulse lasts for 128 clock cycles.
Colin
=====
Quazar : Hardware, Software, Spares and Repairs for the SAM Coupe
1995-2009 - Celebrating 15 Years of developing for the SAM Coupe
Website: http://www.samcoupe.com/
