[Coco] COCO Video

[john dumas]

On 6/19/2013 8:41 AM, Mark Marlette wrote:
> John,
>
> Yes, I have two in my possession, this is of the CoCo3/GIME and not the 6847.
Yeah, that's what I thought. If a '47 BB existed, it must have been 
somewhere other than
Austin.

And Bye the Bye, it is believed by many that the VDG was specifically 
designed
for Tandy (the VideoTex). That *MAY* be true, but the rumor going around 
Austin
during the design phase was that it was for an un-named game company to
make a home game console. Due to the way the VDG project came about, we
may never know....

But when the silicon was available, the buzz became that the supposed 
"game company"
was not going to buy and MOT went looking and found Tandy. That is what 
I was given
to believe at the time. After all this time, I wonder if we can ever get 
documentation
that will give a true and accurate picture. Boisy has done the hard work 
and thanks to him!

cheers,
johnd
>
> Regards,
>
> Mark
> http://www.cloud9tech.com
>
>
>
>
> ________________________________
>   From: john dumas <JohnDumas at austin.rr.com>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Wednesday, June 19, 2013 8:34 AM
> Subject: Re: [Coco] COCO Video
>   
>
> On 6/19/2013 2:39 AM, T. Franklin wrote:
>> I think you're confusing the 6847 with the GIMI. The 6847 was a chip Developed by Motorola for a dumb terminal called TRS-80 VideoTex Terminal, for the farm industry (precursor to the CoCo). The GIMI was breadboarded with discrete components when developing the CoCo3.
>>
>> https://en.wikipedia.org/wiki/TRS-80_Color_Computer
>>
>>
>>
>>
>>
>>
>>
>> The logic of the 6847 is relatively simple and constructing a replacementfor it isn't outside of the realm of possibility. The thing was breadboardedwith discrete logic while being designed, after all.
> If there was a breadboard of the VDG, it was well hidden from the folks
> at the Austin
> Design Center! While doing the Time Domain Analysis of the VDG, I would
> have LOVED
> to have a breadboard to compare with some of the race conditions and the
> one logic
> error, I found....and had to correct.
>
> A breadboard would also have very useful while testing the first
> silicon. If such a BB existed,
> I wonder WHERE it lived? Has anyone actually seen it with their own Mark
> One eyeballs?
>
> Oh and BTW, a BB would have prevented the surprise we got when the first
> silicon powered
> up in one of the two "modes" - green or orange background......I
> remember the "What the...!"
> expressions. Seems that all of us designers involved with the chip
> missed that "feature"
> before finalizing the design.
> My bad!
>
>
> cheers,
> johnd
>