Re: gEDA-user: Symbol style recommendations

[Mark Rages <markrages@xxxxxxxxx>]

On Thu, Mar 19, 2009 at 10:41 PM, Mark Rages <markrages@xxxxxxxxx> wrote:
> 2009/3/19 Peter TB Brett <peter@xxxxxxxxxxxxx>:
>> On Thursday 19 March 2009 21:58:59 Josh Jordan wrote:
>>> I prefer to use actual pinouts in my schematics for two reasons: It helps
>>> you with chip placement because naturally you will tend to place symbols
>>> and lines to get the fewest line crossings.  Going to layout after you have
>>> already decided the best general position for parts makes it much easier.
>>> The second reason is that later on it will be easy to look back to a
>>> schematic that has a similar layout as the board and the same pinouts.
>>
>> We'll have to agree to disagree. When I look at a schematic, I want to be able
>> to quickly and easily work out what the circuit is designed to do, and having
>> the pins on my symbols arranged by function and bus offset rather than by
>> physical position helps a great deal.
>>
>> What you're doing completely defeats the point of having separate schematic
>> and layout diagrams, IMHO.
>>
>> What do you do about parts that have different pinouts depending on what
>> package they're in?
>>
>>                                     Peter
>
> Of course you use the place the part on the schematic with the pinout
> you are using.
>
> When you are troubleshooting a circuit with a scope or analyzer, it
> adds an extra decoding step to have the pin order scrambled.  And it
> really is annoying when you're trying to look at the schematic to see
> where your 64-pin micro has an unused pin free.
>

Resurrecting this old thread as I just ran across an example of
worst-practices regarding IC layout:


http://live.midwesttelecine.com/Screenshot-PIC18F87J50%20FS%20USB%20Plug-In%20Module%20User's%20Guide.png

(or http://tinyurl.com/c97tsp)

This schematic combines the inconvenient form of a physical-ordered
layout with the confusion of pins moved around, and all to a bunch of
named nets anyway.

(Just for the record, this is a dev board with no predefined function,
and a high likelihood that the end user will be scoping signals and
attaching other circuits, so IMHO physical order is called for.)

Regards,
Mark
markrages@gmail
-- 
Mark Rages, Engineer
Midwest Telecine LLC
markrages@xxxxxxxxxxxxxxxxxxx


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user