[Coco] Finally RGB from a coco 2

[lciotti at lrlc.us]

Ed you are working very hard on these projects put me on the list to buy these when they are ready!

Lou

Sent from my iPhone

> On Jul 1, 2015, at 6:53 PM, Zippster <zippster278 at gmail.com> wrote:
> 
> Hi Darren,
> 
> The comparators weren’t behaving as I expected on the first prototype, so I’m laying out a second
> one with optional hysteresis on the LM339s to enhance stability, and individual voltage dividers instead
> of the very hard to adjust networks I had on the first one.
> 
> I may add a header for a piggyback board with a circuit using an AD725 ic for composite and s-video
> (artifact support) that will hopefully be the clearest composite possible on a CoCo2 (in addition to the VGA).
> 
> There’s also a collaborative project I’m working on with Brendan Donahe.  An MC6847 VGA board using an
> Altera Cyclone IV FPGA. I just ordered our development prototype PCBs last week.  This one will support 
> artifacts directly once we have it developed.
> 
> We will definitely have some 6847 VGA options eventually.  :)
> 
> - Ed
> 
> 
>> On Jul 1, 2015, at 3:56 PM, Darren A <mechacoco at gmail.com> wrote:
>> 
>> I think I would rather wait for Ed's 6847-to-VGA project. Any updates on
>> the progress Ed?
>> 
>> - Darren
>> 
>> 
>>> On Wed, Jul 1, 2015 at 1:05 PM, Zippster <zippster278 at gmail.com> wrote:
>>> 
>>> I don’t know.
>>> 
>>> I asked Fred about schematics on Atari Age, he declined, saying he wanted
>>> to offer kits and upgrades.
>>> 
>>> My guess would be the transistor circuit inverts Y and level (amplitude)
>>> adjusts Y, øA, and øB.
>>> The small board probably handles component to RGB matrix conversion, the
>>> the HDMI converter
>>> box as scan-doubler to 31.4khz for the monitor.
>>> 
>>> - Ed
> 
> 
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