X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f
X-Recipient: geda-user AT delorie DOT com
X-Cam-AntiVirus: no malware found
X-Cam-SpamDetails: not scanned
X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/
Date: 14 Nov 2012 15:55:06 +0000
From: "Peter C.J. Clifton" <pcjc2 AT cam DOT ac DOT uk>
To: geda-user AT delorie DOT com
Subject: Re: [geda-user] slotting
Message-ID: <Prayer.1.3.5.1211141555060.15335@hermes-1.csi.cam.ac.uk>
In-Reply-To: <CACPio-4cDVS+vmowijmZ6Y9E0+rXoEimc9ugZqTPGvOKQvoqow@mail.gmail.com>
References: <CACPio-7O1OS0Z-NkOJmzTvxSFf+v9j6yFM8F6xRXeZvTjDUK8A AT mail DOT gmail DOT com>
 <50A2B84F DOT 4080204 AT laserlinc DOT com>
 <CACPio-4+wJj6WY-GsJhskmZicM1mn6YKoRc4kVVP9ABXLpZYYg AT mail DOT gmail DOT com>
 <50A3AAA6 DOT 1080704 AT laserlinc DOT com>
 <CACPio-4cDVS+vmowijmZ6Y9E0+rXoEimc9ugZqTPGvOKQvoqow AT mail DOT gmail DOT com>
X-Mailer: Prayer v1.3.5
Mime-Version: 1.0
Content-Type: text/plain; format=flowed; charset=ISO-8859-1
Sender: "Peter C.J. Clifton" <pcjc2 AT hermes DOT cam DOT ac DOT uk>
Reply-To: geda-user AT delorie DOT com
Errors-To: nobody AT delorie DOT com
X-Mailing-List: geda-user AT delorie DOT com
X-Unsubscribes-To: listserv AT delorie DOT com
Precedence: bulk

On Nov 14 2012, Nathan Stewart wrote:
[snip]

>I was unclear about slotting of broken out symbols, or where the 'slots'
>are not identical (such as where I was using slots to represent both sides
>of the optoisolator).

In the gEDA world, this isn't slotting per-se, but having multiple symbols 
to connect different parts of a complex chip is common practice.

What I would do is to ignore slots, and make two separate symbols (if you 
want to separate transmit and receive). Each will be instantiated with the 
same refdes (e.g. OPTO1 or something like that), and the netlist will "just 
work". Each symbol can just use the pins it requires.

This probably won't play well with the renumber tools out there, and I'm 
not sure it is a good idea to try and trick them by invoking slotting.

Myself, I'd make an opto-pair one symbol (containing transmit AND receive), 
and would only use slotting if I had multiple opto isolators within the 
same chip.

Finally.. if you do use multiple symbols anywher, there is (or was?) a 
problem you have to work around, in that when picking up the symbols to 
retrieve attributes from (e.g. for forwarding to PCB layout), it was not 
clear which of the two symbols would be scanned for attributes.

To get around this, add the "footprint=..." and any other attributes you 
need to be "machine" readable to both halves of the symbol.

(If this issue hase has been resolved already, someone please let me know).

Best wishes,

Peter Clifton


Best wishes,

Peter Clifton