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Re: Using VGA/LCD monitor with a IIgs?



MdntTrain wrote:
On Dec 3, 12:23 pm, sporadic <sporadica...@gmail.com> wrote:

On Dec 3, 8:34 am, MdntTrain <j...@cimmeri.com> wrote:






On Dec 2, 11:55 pm, sporadic <sporadica...@gmail.com> wrote:

On Dec 2, 7:26 pm, MdntTrain <j...@cimmeri.com> wrote:

On Dec 2, 12:03 pm, sporadic <sporadica...@gmail.com> wrote:

On Dec 2, 5:10 am, Steven Hirsch <snhir...@gmail.com> wrote:

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:

http://picasaweb.google.com/sporadically/GSOnAcer24LCDWithAmbery#

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.

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

  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:

http://picasaweb.google.com/sporadically/GSOnAcer24LCDWithAmbery#

Jimmy- Hide quoted text -

- Show quoted text -

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.

  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 -

- 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.

;-)

The duration of a horizontal line is much less problematic than
the fact that this box's input sampler clock will not lock to
a multiple of the IIgs dot clock.

If it won't lock, then it must at least oversample significantly
(3x-4x) to avoid generating a lot of aliasing artifacts.

-michael

NadaNet and AppleCrate II: parallel computing for Apple II computers!
Home page: http://home.comcast.net/~mjmahon

"The wastebasket is our most important design
tool--and it's seriously underused."