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Re: looking for an S-100 expert builder to build and test prototype board

Hi!  Thanks Neil, Dave, and Kipp!  I appreciate your support!

Well the answer to the whole VGA connection issue is "kinda sorta".

The V9938 (and V9958 with an almost identical pin out) support RGBI
(TTL) at NTSC/PAL dot clock frequencies in addition to composite.
Many recent LCD monitors also supply a composite video input channel.

There is another project at N8VEM (ColorVDU) on the ECB side which has
circuitry that *potentially* allows an RGBI to be converted to a VGA
compatible monitor.  I will be sending that PCB to manufacturing this

However, this does not resolve the differences in dot clock.  This
trick relies on the recent LCD monitors which can sync to lower than
VGA dot clocks because they share circuitry with their TV equivalent

There are a few very rare CRT type VGA monitors which can sync at NTSC/
PAL frequencies.

In other words, there is a *possibility* under the right circumstances
of VGA "sorta" compatibility.  This is not a sure thing though and
will depend on your monitor.  Recent LCD monitors have a decent chance
of working though IMO.  This is something we'll have to hash out in
the prototyping area on the PCB.  It's why we need a build and test
phase to sort out what is real versus what is wishful thinking.

I very much appreciate your support.  Please consider.  Thanks and
have a nice day!

Andrew Lynch

On Dec 14, 10:00 pm, yoda <y....@r2d2.org> wrote:
> Hi Andrew
> I was looking at the schematics - is there any plans to do VGA instead/
> as well as composite video.  It seems that composite will push the
> limits at 80 columns ?
> I will have to order some parts but should have them before the board
> arrives.
> Dave
> On Dec 14, 6:23 pm, lynchaj <lyn...@yahoo.com> wrote:
> > Woo Hoo!  Two volunteers!  That's great!
> > I've uploaded the KiCAD file set, schematics, and PCB layout to the
> > N8VEM wiki here:
> >http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder¶m=S-100%20VDP
> > OK, so we've got a design and builders to put it together.  This is
> > great!
> > Does anyone want to pitch in to get some prototype PCBs made?
> > Typically that's $150 for 5 PCBs athttp://www.33each.com
> > You don't have to pay for it all or even build a board if you want to
> > participate.
> > If you buy a board I can send it to one of the volunteers.
> > Please remember though this is a high risk venture and no guarrantees
> > it will work.
> > However, I think there is a pretty good chance and if we spread the
> > risk and work out a bit everyone benefits!
> > Thanks and have a nice day!
> > Andrew Lynch
> > On Dec 14, 6:50 am, lynchaj <lyn...@yahoo.com> wrote:
> > > Hi,
> > > There is an S-100 board project that is ready for prototype build and
> > > test but the project is "stuck in the mud" due to availability issues
> > > (aka "real life") of the original design team.
> > > Is there anyone who would like to take on a build and test of a rather
> > > ambitious S-100 board?  The project I am referring to is the S-100 VDP
> > > which is a video board based on the V9938/V9958 video display
> > > processor.
> > > This board has potential for greatly improved color graphics, 80
> > > column text, etc using the latest of the VDPs which descended from the
> > > original TMS9918.
> > > I have a design schematic and PCB layout which is ready for prototype
> > > build and test.  However it will stay on the "black board" until some
> > > builder can make it a reality.
> > > The design could even be extended to include audio (AY-3-8910 or
> > > similar) once we get the video section working.  This would provide a
> > > measure of MSX compatibility for the S-100 bus systems.  There is
> > > quite a bit of stuff we can export from the N8VEM N8 "all in one"
> > > project to this board to accelerate an improved design.
> > > This board is deceptively simple looking but is not for the feint of
> > > heart.  Video boards never are...
> > > Anyone interested?  Thanks and have a nice day!
> > > Andrew Lynch- Hide quoted text -
> - Show quoted text -