[Coco] new mylars

[Mark Marlette]

Yep, no doubt. All part of the learning curve.


Another view of the vintage platform, yes slow speed etc.....

The CPLDs I use are 175MHZ+ devices, so slow transitioning edges, race conditions, etc are all seen by these new chips that the old vintage ones would have never responded to. So yes, it is a double edge sword.

The prices have dropped and the auto-router wasn't included, that was extra.
 
Mark Marlette 
http://www.cloud9tech.com 
mark at cloud9tech.com 


________________________________
From: Zippster <zippster278 at gmail.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> 
Sent: Tuesday, August 11, 2015 2:13 PM
Subject: Re: [Coco] new mylars


Yes, I know, but those things don’t really come into play at the slow speeds and simple circuits
involved with 80s computers like the CoCo.

It’s probably too much for a beginner to think about high-speed differential pairs and the like.
It can be overwhelming enough just getting started in self-taught design.  Let them get the basics
down first before learning the more advanced concepts.

A quick check shows that ORCAD is indeed not cheap…  $3,000 to $7,000 and up, putting it permanently
out of the reach of almost all hobbyists.  The good news is that excellent boards can be made with the free
and less expensive tools, though it may take more effort.

- Ed





> On Aug 11, 2015, at 1:11 PM, Mark Marlette <mmarlette at frontiernet.net> wrote:
> 
> I did layout my first memory board by hand, just to say I did it.
> 
> Took me, IIRC a full day. This was a simple board as well.
> 
> It took the Specctra, yes, 8 seconds. The SuperIDE took the same computer over 200 seconds to route that card. Every trick in the book was used on that board as it should have been a four layer card.
> 
> Ground bounce is a bad thing. I have had the luxury of taking high speed layout classes at work, priceless! Matching differential signals on trace lengths very critical.
> 
> Been with Orcad since it it's first version release over 25 years ago.
> 
> I'll agree with your approach on the simpler boards, but when it comes to power planes, it is hard to keep them on just one side in a complex design. A trick is to have planes on both sides then tie together with vias....makes a small cap.
> 
> What is nice is that the tools are there, something even back in the late 90's where very expensive are now free or low cost.
> 
> At work they spend several seven digits a year with Mentor Graphics......I won't be moving to that platform any time soon..... :)
> 
> 
> Mark Marlette 
> http://www.cloud9tech.com 
> mark at cloud9tech.com 
> 


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