On Wed, 15 Jan 2020 17:40:26 +0100, Peter Graf via Ql-Users wrote:

> Thierry Godefroy wrote:
> > In fact, I found out today that by increasing the sample rate to 1260 (from
> > the 1200 I used so far) on the OSSC, I could get it to output a 1024x512
> > (without scan doubling) or 2048x1024 (with it) resolution in the 480p HDMI
> > signal format... and the good news is that the monitor accepts it !
> What does the OSSC do then...
> a) scale 512 to 480 vertical pixels?
> b) somehow make the monitor display a 512 pixel signal?
> c) just output 480 pixels, and 32 lines are lost?

It's b)
As you can see on the high res photos, the monitor menu displays the
input resolution: 1024x512 (without x2 scan) or 2048x1024 (with it)...

That's why with the 1260 scan rate I get a pixel-perfect picture (or
very, very close to it, and certainly as good as, if not better than,
what my old 17" CRT can display).

> > Very interesting, since the best solution would indeed be to gain a
> > standard resolution output on the Q60.
> My personal preference would be a solution that includes more VRAM, so
> it is not interpolated, but an actually usable resolution.
> Besides lack of time and the BGA soldering issue, I remain unsure if
> such a massive board modification is appropriate for a historic computer.
> A lot depends on the question, what do we actually prefer today: Keeping
> the historic machine alive, or any 68060 machine that has decent video
> and runs SMSQ/E?

That's why I always suggested a 800x600 SVGA mode to replace the 1024x512
one... Granted, you loose 44288 pixels, but 800x600 is totally decent and
workable (under both SMSQ/E and Linux), and won't require any additional
VRAM, "just" needing a reprogramming of the FPGA(s) (or so is my wild

You then get both of "keeping the historic machine alive" and a "68060
machine that has decent video and runs SMSQ/E"... :-P

It might as well be possible to "cheat" a bit with nowadays' LCD monitors,
and see if they can be persuaded to display a 800x640 mode (i.e. to sync
640 lines in each frame with timings close enough to a true 800x600 mode),
which would be only 12288 less pixels when compared to 1024x512...

This said, the OSSC totally does the job for me, and I'm not worried any
more about the remaining lifetime of my last CRT (which I repaired myself
twice already, so I don't expect it to survive much longer)...


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