Re: gEDA-user: SOT143

[Bill Wilson <billw@xxxxxxxxxxxxxx>]

On Sun, 4 Sep 2005 14:25:35 +0200
Karel Kulhavy <clock@xxxxxxxxxxxxx> wrote:

> If I find in PCB Window -> Library -> ~geda -> SOT143, SMT transistor, 4
> pins and I want it, what should I put into footprint= in gschem?
> 
> sot143
> SOT143
> sot 143
> SOT 143
> sot_143
> SOT_143
> sot-143
> SOT-143
> 
> ?
> 
> Where is it possible to obtain algorithm to translate
> "SOT143, SMT transistor, 4 pins" into the string that is necessary to
> put into footprint=?

>From the description line:

    SOT143, SMT transistor, 4

You just use the SOT143 string directly as the footprint value.  That
string should be defined to be a macro which expands with the right
SMT footprint parameters in the geda.inc file.  Use the string exactly
and case must match.

If you try such strings from the descriptions and don't get what
you expect, do this to help debug what's going on:

1) cd /usr/local/share/pcb/m4
   ( or to wherever your PCB m4 install directory is)

2) grep SOT143 *   gives:
    geda.inc:define(`PKG_SOT143',   `PKG_SMT_TRANSISTOR4( `$1', `$2', `$3', 19, 21)');
    geda.list:geda_SOT143:SOT143:SOT143
    geda.m4:define(`Description_geda_SOT143',       ``SMT transistor, 4 pins'')

3) So you now know that in geda.inc, a macro SOT143 is defined which
in turn calls another macro SMT_TRANSISTOR4.  (The "PKG_" is always
prefixed for you, so you don't include it in the footprint value).

The first three args are always handled for you in gsch2pcb, so you can use as
your footprint either:

    SOT143
or
    SMT_TRANSISTOR4 19 21

Bill