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;
        bh=TB+cf7PEImV/ZIy5fQC0WLch79Yr9gTBf7YuobX91D0=;
        b=bSfQwtMXO/+RxXaLuXf5sEVA+u+oZKR41Xq4QGP/N/tt5gZI9T1dRefmmWSHK6OfwP
         CDSTBE2sIvYpiKkzlJqG2WYBfftoe3z3L5QR31i2czsSlMnM/X/0crO/UUIVO+oRJ3BK
         XEORZdLC8K8XDuDlZo+8Xta5nmOm0SdGa4dTs=
MIME-Version: 1.0
In-Reply-To: <CAF0dY_sin2XBTkubdmFYrtR0Fjf0BauT+o+owP0LoEx-4E5w7A@mail.gmail.com>
References: <CAF0dY_vaL=4949F9h1eVE7kxiWA2=+mtOSCygsLvpk+Ds3g1+Q AT mail DOT gmail DOT com>
	<CACNnPRkzfe0ErA7nwn3_kBJVkiLfbnf5g-byt14Q1WkJ899dyg AT mail DOT gmail DOT com>
	<CAF0dY_uets66CFRYYhnufy-R_WwqxYCaaycNCvScAZd1ycYznA AT mail DOT gmail DOT com>
	<201201031452 DOT q03EqBXC028986 AT envy DOT delorie DOT com>
	<CAF0dY_u_oZxVN57x-oAZONT0N=RK-oJCM3orzcxjuaEHxQ_2Ug AT mail DOT gmail DOT com>
	<201201031548 DOT q03FmaQj031068 AT envy DOT delorie DOT com>
	<CAF0dY_v1d-O2kazuNBt02y7SaMSCB+2tu7FxsGYCVC2Tz9ZkSg AT mail DOT gmail DOT com>
	<201201031606 DOT q03G6Nr7031765 AT envy DOT delorie DOT com>
	<CAF0dY_sin2XBTkubdmFYrtR0Fjf0BauT+o+owP0LoEx-4E5w7A AT mail DOT gmail DOT com>
Date: Tue, 3 Jan 2012 15:00:45 -0500
Message-ID: <CAAegBQdQgFNX-0z9SOHoS8jX+4eKAxG=AadpTvqpw_T894J1Fg@mail.gmail.com>
Subject: Re: [geda-help] Footprints
From: Stephen Trier <stephen DOT trier AT gmail DOT com>
To: geda-help AT delorie DOT com
Content-Type: multipart/alternative; boundary=14dae9399dcda0bd1704b5a52749
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
Precedence: bulk

--14dae9399dcda0bd1704b5a52749
Content-Type: text/plain; charset=ISO-8859-1

Chetan,

Is it possible that you are finding some confusion between symbols and
footprints?  Symbols are the familiar elements of scematic: two parallel
lines for a capacitor, a triangle for an op amp, and so on.  Footprints are
the shapes that must be on a PC board for components. A through-hole
resistor will have two holes a certain distance apart, a surface-mount
resistor two pads, and an op amp in a DIP package will need eight holes
(with sorrounding copper) for its pins.

Thus, a component is represented by two things: a symbol in gschem and a
footprint in PCB. In order to completely describe a component, it needs a
symbol on the schematic in gschem, and that symbol needs a "footprint="
attribute that will tell PCB which footprint from its library to use.

Some symbols is gschem's library and on gedasymbols.org have footprint
attributes already included. Others do not, and you must add the footprint
attribute yourself. This is especially helpful for symbols such as
resistors, which come in a dizzying variety of shapes and sizes, and
perhaps less helpful for certain chips that come in only one package. Even
a simple through-hole resistor can be mounted in either a standing or a
flat position, each of which requires a different footprint.

--14dae9399dcda0bd1704b5a52749
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

<p>Chetan,</p>
<p>Is it possible that you are finding some confusion between symbols and f=
ootprints?=A0 Symbols are the familiar elements of scematic: two parallel l=
ines for a capacitor, a triangle for an op amp, and so on.=A0 Footprints ar=
e the shapes that must be on a PC board for components. A through-hole resi=
stor will have two holes a certain distance apart, a surface-mount resistor=
 two pads, and an op amp in a DIP package will need eight holes (with sorro=
unding copper) for its pins.</p>

<p>Thus, a component is represented by two things: a symbol in gschem and a=
 footprint in PCB. In order to completely describe a component, it needs a =
symbol on the schematic in gschem, and that symbol needs a &quot;footprint=
=3D&quot; attribute that will tell PCB which footprint from its library to =
use.</p>

<p>Some symbols is gschem&#39;s library and on <a href=3D"http://gedasymbol=
s.org">gedasymbols.org</a> have footprint attributes already included. Othe=
rs do not, and you must add the footprint attribute yourself. This is espec=
ially helpful for symbols such as resistors, which come in a dizzying varie=
ty of shapes and sizes, and perhaps less helpful for certain chips that com=
e in only one package. Even a simple through-hole resistor can be mounted i=
n either a standing or a flat position, each of which requires a different =
footprint.<br>

</p>

--14dae9399dcda0bd1704b5a52749--