Re: [avr-chat] Schematics & PCB design software

[David Kelly]

On Feb 16, 2009, at 5:55 PM, Kreyl wrote:

>  I  would  like  to  use free schematics & PCB design software. So, I
>  would  like to get any suggestions & recommendations. There is a lot
>  of such software, it's hard to select one.

For Macintosh and Windows http://mccad.com/ works well. The free  
version might be too limited to be of any use. But its free, so you  
have to answer that question for yourself.

I've owned the full version since 1991 or 1992. I don't like the  
provided schematic symbols or footprints but it has had built-in  
library editors since day one. Is better to create your own symbol  
that you know is right than to trust someone else's without verifying.  
Takes about as long to create as to verify.

ECAD is not easy to do right. Took a while to get a hang of the flow  
of Mccad tools. In their classic tools you have schematic libraries,  
package files, and PCB libraries. Assign a "ClassID" to schematic  
symbols in the schematic libraries. Then cross reference that to a PCB  
footprint name in a PCB library. This allows you to create multiple  
package files so that one creates a through-hole PCB, another does  
SMT. And one can manually package one part at a time selecting which  
package file you want.

Package files also bundle multiple components into one chip. 74HC04's  
for example. CPU chips usually have more pins than looks good on only  
one sheet so I break them up into U1.A, U1.B, U1.C ... whatever it  
takes. One section for data and address lines, one section for power  
and ground, another for analog inputs, often one section each for Port  
A, Port B, Port C, etc. Makes it easy to split the CPU across multiple  
schematic sheets.

The free version doesn't allow projects to span multiple schematic  
sheets.

--
David Kelly N4HHE, address@hidden
========================================================================
Whom computers would destroy, they must first drive mad.