[Coco] COCO Video

[john dumas]

On 6/24/2013 9:25 PM, Mike Pepe wrote:
> John- what other methodologies were used to prototype ICs at Mot during that
> time, if there was no traditional breadboarding being used?
Classic Stone Age.
1-Logic simulators for sections, or even complete chips.
     [The logic was _tiny_ compared to today's chips!]
    To sim MOS, we first used 3 state, then 5 state simulators,
    which would better model the states that mos xistors could
     produce: i.e. 1, 0, floating, "soft 1", and "soft 0".
2-TTL breadboards.
3-Time Domain Analysis - Similar to xistor emulation in Spice.

#1 & #2 to verify the logic; #3 to size devices to correct electrical
characteristics.

Much later HDL was used to simulate (and create) the larger
chips. When I retired in '99, the HDL design was being implemented
in FPGAs to check out functionality before releasing to production.
And, of course, the entire design cycle was CAD from spec to chip,
no more typing pool to do the specs, no hand drawn logic diagrams,
and (thank gawd) no more ruby to peel, check and patch with tape!
[hoping the database - on punch cards - got updated! Many horror
stories there........]

cheers,
johnd
>
>> -----Original Message-----
>> From: coco-bounces at maltedmedia.com [mailto:coco-
>> bounces at maltedmedia.com] On Behalf Of john dumas
>> Sent: Monday, June 24, 2013 3:56 PM
>> To: CoCoList for Color Computer Enthusiasts
>> Subject: Re: [Coco] COCO Video
>>
>> On 6/24/2013 12:52 AM, Mike Pepe wrote:
>>> John, you've probably been asked this before, but what do you think of
>>> the theory that the 6847 and 6883 were designed specifically for
>>> Tandy? The 6883 in particular smells like a breadboard of TTL glue
>>> that got the old shrinkeroo into a 40 pin DIP.
>> The SAM (6883) *may* have been designed specifically for tandy.
>> But, my memory is that the VDG was not, but picked up by tandy after the
>> VDG was in production.....
>>
>> The SAM may have been breadboarded to replace the glue logic around the
>> VDG and MPU. That might explain the persistent belief by some that there
>> was a VDG breadboard. I am unaware of any real evidence that there was. If
>> a VDG breadboard existed I was CHEATED!!!
>> A breadboard would have been a big help at the circuit design/layout
>> phase.....
>>
>>
>>
>> cheer,
>> johnd
>>>> -----Original Message-----
>>>> From: coco-bounces at maltedmedia.com [mailto:coco-
>>>> bounces at maltedmedia.com] On Behalf Of john dumas
>>>> Sent: Thursday, June 20, 2013 2:33 PM
>>>> To: CoCoList for Color Computer Enthusiasts
>>>> Subject: Re: [Coco] COCO Video
>>>>
>>>> On 6/20/2013 3:02 PM, Mike Pepe wrote:
>>>>> John, if anyone should have seen it in breadboard form, it should have
>>>>> been you!
>>>> Yeah, that's what I've always thought.
>>>> Of course, there was a lot that never found it's way down to the
> "grunts".
>>>> And the VDG project, more than any other at the time, was a prime
>> example
>>>> of that. There surely was "stuff" going on in other groups - MOT was
> very
>>>> Bottoms-Up at that time - that never got well known in other
> groups.......
>>>> I don't think Boisy could have picked a more difficult task - history
>>> wise, that
>>>> is........
>>>>
>>>>
>>>>
>>>> Now his Atari design (Liber809) work...WOW, that looks really tough.
>>>> And truly amazing.
>>>>
>>>> cheers,
>>>> johnd
>>>>
>>>>
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