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Re: IIGS mass storage ideas
Smohn Jith wrote:
"Ed Eastman" <noone@nowhere.net> wrote in message
news:dpkduc$res$1@unlnews.unl.edu...
Sean Fahey wrote:
Scan-doubler or mirroring video card that allows GS video to be displayed
accurately on modern VGA monitors
OK, I'll test my latest one and get back to you. :)
Thankx,
Ed
I was looking into this for a while. There is a chip made by AVERlogic that
does it, although it's a bit pricey. I think the device should plug in the
back, and then hook up to the monitor. I have seen on the web where someone
displayed VGA using a PIC for a home built computer. You might be able to
use the PIC to process the analog RGB to digital VGA.
Generating a little VGA is trivial--capturing CGA RGB and re-generating
it as VGA is not a PIC-sized job. Some specialized 3-channel digitizing
hardware is needed, and a dual-ported video memory, plus 3 channels of
video DAC for output. If the capture cannot lock to the IIgs dot clock,
then it will be necessary to oversample by 2-3x to get a good image,
which works out to a 28-40MHz sampling rate!
If you build the converter into the IIgs, the dot clock is available, so
it could run at 14MHz (except for SHR mode).
Actually modifying existing monitors is interessting.....I wonder which is
easier....
I expect this would be *much* easier, since a lower sweep frequency
puts less stress on everything.
Frankly, since every TV is an RGB monitor with a tuner attached, it
is hard to imagine that there would be a shortage (until SD TV is
gone for a decade).
-michael
Music synthesis for 8-bit Apple II's!
Home page: http://members.aol.com/MJMahon/
"The wastebasket is our most important design
tool--and it is seriously underused."