RE: gEDA-user: Documentation for learning EDA with gEDA?

[Alex Perry <alex.perry@qm.com>]

> So far, trying to draw just a few simple designs in gschem has been
> like pulling teeth compared to sketching them out on paper.  I have to
> believe that I'm doing something very wrong, probably because I don't
> understand the idioms common in EDA software.  Perhaps I just need
> practice and more familiarity with the key bindings.

You're seeing a difference that is akin to trying to explain why C++
(or ADA for that matter) is a better language than using Basic ...
using the hello world program as an example to make your point.

The tools keep track of the important things on schematics that have
several hundred components and thousands of interconnect nets.
Designs of that size are virtually impossible to get right ... by hand.
We also tend to do the little boards using the same tools, not because
it's saving time directly, but because it deals with all the documentation
and tracking activities that are needed on product-driven engineering.

> On a slightly related note, I'm using lots of chips from the LS74*
> family (the "TTL Cookbook" was a wonderful discovery) that include
> many identical gates on one chip.  It occurs to me that if I choose
> the wrong slot in my gschem capture for certain gates, the resultant
> pcb is going to need way more layers than I care to pay for.  Is there
> some program that can help me avoid resorting to trial-and-error to
> pick the right slot for each gate?

In commercial packages, that kind of swapping around is usually
handled by the PCB layout tool using metadata provided in the schematic.
As far as I know, none of the gEDA tools support that approach.

Also, if you're doing non-trivial amounts of TTL work, you might want
to use "icarus" and programmable logic chips ... it's a lot easier.