jm@tekadg.UUCP (Jeff Mizener) (11/05/84)
[]
I tell ya, I got soooo many questions. Just wish I had some answers...
Problem: I dislike looking at the text characters on my amdek 300a
when connected to my ibm color/graphics card. But setting the
6845 crt controller to interlace mode smears the picture.
I assmue that this is because the amdek has insufficient bandwidth
to accomodate the interlaced signal (or maybe it's the cable
playing low-pass filter).
Proposal: Connect an ibm direct drive monochrome monitor to the RGB output
of the color card. Then set the 6845 to interlace mode and see what
happens.
Question: Am I gonna blow up the whole mess? Around here, technical info
is scarce (odd as that may seem), and ibm doesn't fill in all the
blanks in my mind with what they do say. The very minimum I would
say is that I need to make a new cable. Then I may have to invert
one of the outputs (maybe in software?).
I'm afraid my name ain't Mr. Video, so this one goes out to you all.
Next Subject: What We Need is a library of "Patches, Hints And Kinks" for
the PC user. It would save re-inventing the wheel over and over,
and make hacking (and I use that term advisedly) less fustrating.
This is the sort of thing that would go in the file. As would
solutions to the "reset memory size after startup" and
"reset button" problems...
Comments?
Jeff Mizener / Tektronix Portables ADG / Beaverton OR
{ucbvax,decvax,purdue,uw-beaver,hplabs,allegra,ihnp4,ogcvax}!tektronix!tekadg!jm
ARPA: tekadg!jm.tek@udel-relay CSnet: tekadg!jm@tek
"May your stone always grow rolling grass that is greener underneath."dmt@hocsl.UUCP (11/07/84)
REFERENCES: <51@tekadg.UUCP> > Subject: monochrome monitor to rgb connection question > > Problem: I dislike looking at the text characters on my amdek 300a > when connected to my ibm color/graphics card. But setting the > 6845 crt controller to interlace mode smears the picture. > I assmue that this is because the amdek has insufficient bandwidth > to accomodate the interlaced signal (or maybe it's the cable > playing low-pass filter). > > Proposal: Connect an ibm direct drive monochrome monitor to the RGB output > of the color card. Then set the 6845 to interlace mode and see what > happens. > > Question: Am I gonna blow up the whole mess? Around here, technical info > is scarce (odd as that may seem), and ibm doesn't fill in all the > blanks in my mind with what they do say. The very minimum I would > say is that I need to make a new cable. Then I may have to invert > one of the outputs (maybe in software?). The Monochrome monitor is seriously incompatible with the output of the color board. (1) The signals have different meanings and senses. For instance, the mono monitor responds to intensity signals on two leads, while the color board RGB output is sorted by color and the composite output doesn't have separate sync leads (needed by the mono monitor). (2) The mono monitor runs at a higher horizontal sweep frequency (by about 20% -- nontrivial). My guess is that would cause it to simply not work, though I've heard rumors about this sort of thing turning the IBM monitor into a blue smoke generator. On balance, I'd go with a mono board and the mono monitor (in fact, I did ten months ago). It generates a DIFFERENT character set, that's much easier on the eyes. > Next Subject: What We Need is a library of "Patches, Hints And Kinks" for > the PC user. It would save re-inventing the wheel over and over, > and make hacking (and I use that term advisedly) less fustrating. > This is the sort of thing that would go in the file. As would > solutions to the "reset memory size after startup" and > "reset button" problems... > Comments? Except for Norton's book, "Inside the IBM PC", which deals with software only, I can't think of anything that fits your bill except the accumulated annals of net.micro.pc. Continue to subscribe, and ENJOY. Happy hacking. Dave Tutelman