Re: Using VGA/LCD monitor with a IIgs?

[MdntTrain <js@cimmeri.com>]

On Dec 3, 12:23 pm, sporadic <sporadica...@gmail.com> wrote:
> On Dec 3, 8:34 am, MdntTrain <j...@cimmeri.com> wrote:
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>
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> > On Dec 2, 11:55 pm, sporadic <sporadica...@gmail.com> wrote:
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> > > On Dec 2, 7:26 pm, MdntTrain <j...@cimmeri.com> wrote:
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> > > > On Dec 2, 12:03 pm, sporadic <sporadica...@gmail.com> wrote:
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> > > > > On Dec 2, 5:10 am, Steven Hirsch <snhir...@gmail.com> wrote:
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> > > > > > sporadic wrote:
> > > > > > >> Can you publish some screen shots?  In particular, I'd like to see what the
> > > > > > >> 80-column text mode looks like.  I'm not a gamer, but do care about being able
> > > > > > >> to use programming tools.
> > > > > > > Here are a few pics I just took:
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> > > > > > >http://picasaweb.google.com/sporadically/GSOnAcer24LCDWithAmbery#
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> > > > > > I don't think any of those are 80-column text mode, are they?  And, as Mike
> > > > > > added, it would be nice to see the GSOS desktop.
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> > > > > Pics 1 & 2 are 40 columns, 3 & 4 are 80 columns.  I'm waiting for the
> > > > > MicroDrive to show up so until then, I probably won't have easy access
> > > > > to the GSOS desktop.  I'll look for the system 6 setup disk, it's
> > > > > gotta be here somewhere.
>
> > > > > Jimmy
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> > > >    A friend tested this unit.  It crapped out on 16mhz video
> > > > (640x200).  Maybe you'll have better luck.
>
> > > >       jS
>
> > > So is the GS Finder desktop 640x200?  I nearly broke out in a cold
> > > sweat when I read this and I had to find the GSOS disk.  Well, I'm
> > > still happy to report that it's working for me.  I've updated the
> > > picasa album with 3 more pictures from the Finder desktop.  I also
> > > found a disk labeled Slide.3200.Vol#3, and ShowAll 3200 SmallPic,
> > > which I vaguely recall as the palette switching 3200 color pics.  They
> > > also displayed via the Ambery on the Acer 24" LCD.
>
> > > I'll be happy to take more pictures this weekend, with better lighting
> > > and steadier hands:
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> > >http://picasaweb.google.com/sporadically/GSOnAcer24LCDWithAmbery#
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> > > Jimmy- Hide quoted text -
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> > > - Show quoted text -
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> > Spor, see all those alternating lines that Michael points out?
> > That's what I meant by "crapping out" on the 16mhz (640x200) video.
> > You do get video, and decent b&w video at that, but I personally find
> > the striping unacceptable.
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> >    jS
>
> Ah ok, it's been so long since I seen the Finder, I don't really
> recall how it should look.  I had interpreted "crapped out" as no sync/
> no display.  Well, I think given my intended usage, the Ambery box
> still meets my needs so I'm going to keep it until the GS2VGA solution
> becomes available.  Bummer!  I'll send an email to Ambery and see if
> this is something they can address in the design.  What resolutions
> does Amiga support?  Ambery states Amiga is supported, so is the
> 640x200 16MHz signal found on Amigas as well?
>
> Jimmy- Hide quoted text -
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> - Show quoted text -

The problem, I believe, is twofold.  One, the IIgs is using
dithering... deliberately displaying, as Michael pointed out,
alternating lines of different colors in order to phosphor mix a new
one.  The Ambery is faithfully showing these lines, but your monitor
isn't doing the mixing (as a low dot pitch crt would have).

The second problem is aliasing.   Appears the Ambery isn't quite
locking onto the IIgs dot clock correctly.. thus some black lines and
other unwanted artifacts are showing.    This could be because of
Apple's 64 1/2 cycles or whatever.  The Amiga likely has truer video
timing, easier to lock on to.

If I said anything wrong, someone please correct me.

 jS