X-Authentication-Warning:	delorie.com: mail set sender to geda-help-bounces using -f
X-Recipient:	geda-help AT delorie DOT com
DKIM-Signature:	v=1; a=rsa-sha256; c=relaxed/relaxed;
	d=gmail.com; s=gamma;
	h=mime-version:in-reply-to:references:date:message-id:subject:from:to
	:content-type:content-transfer-encoding;
	bh=ekiPOVk8RLFkxOTm9nUYaIzx5lptViGgbRbCOtH1+6s=;
	b=iO5QJduYwzWb/+5s/lz1S9fsTbZ9SFeu0XO47hZlu/IXeybwnYNSJ02za5uIaHxn9V
	BhX8a/Gnl9SJGm8yD66wjq3WenRp0NT4cZC72MxPhFaepOhw4aeLxosqyY9LmybOMcW6
	u5XqS/YoEehNBm0CAWCv9cfTVIcFgW7bSIlFM=
MIME-Version:	1.0
In-Reply-To:	<201202151829.q1FITZgo006033@envy.delorie.com>
References:	<CAErn8c+C8mBVmqtmcrkZroq-XPa8XgOso3Vv3WOk0miqq_0pTQ AT mail DOT gmail DOT com>
	<201202151829 DOT q1FITZgo006033 AT envy DOT delorie DOT com>
Date:	Fri, 17 Feb 2012 11:16:16 -0500
Message-ID:	<CAErn8cJO8mV6qCFSrrKgQ1iDYQzb4nUwxFjN_2+hLgX+Dbp5Gw@mail.gmail.com>
Subject:	Re: [geda-help] How can I route multi-pad signals?
From:	Luis Emiro Linares <macgyveremir AT gmail DOT com>
To:	geda-help AT delorie DOT com
X-MIME-Autoconverted:	from quoted-printable to 8bit by delorie.com id q1HGGLsL014034
Reply-To:	geda-help AT delorie DOT com
Errors-To:	nobody AT delorie DOT com
X-Mailing-List:	geda-help AT delorie DOT com
X-Unsubscribes-To:	listserv AT delorie DOT com

Thanks for your advice. The chip is the FDMF6707 DrMOS module from
Fairchild. I'm doing the PCB footprint and the gschem symbol. I have
now the following questions:

1. Could you please elaborate on how, if the pads have different pin
numbers, the autorouter will know?
2. For the gschem symbol, Is it valid for me to define a multi-pad
signal (i.e. PGND) by setting its pinseq and pinnumber both equal to a
comma-separated list of the pad numbers to which it corresponds in the
footprint?

On Wed, Feb 15, 2012 at 1:29 PM, DJ Delorie <dj AT delorie DOT com> wrote:
>
>> I have made the footprint of a 40-pad QFN chip + 3 hidden pads
>> underneath. There are 6 signals that are to be connected to several
>> of the pads, both on the border and underneath the package. Is it
>> possible to instruct the PCB autorouter about this multiple
>> connections?
>
> In general, if the pads have different pin *numbers* [*] the autorouter
> will know that they all need to be connected.
>
> However, I've found that it's often better to hand-route the traces
> *under* the chip first, and let the autorouter take care of the rest.
> Likewise, the autorouter isn't that smart about power/ground nets,
> since they usually have different rules than regular signals.  I do
> all my bypass caps and power/ground planes first, fan out any
> problematic pins, then see how the autorouter does.
>
> For more specific help, you'll need to tell us which chip it is :-)
>
>
> [*] i.e. same label, different pins, vs overlapping pins/pads with the
>    same number forming one oddly-shaped "pin"



-- 

Luis Emiro Linares García
------------------------------
Físico - Ingeniero Electrónico
Universidad de los Andes
Bogotá D.C., Colombia.

- Raw text -