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Re: gEDA-user: Symbol with 20 pins for a module of 40 connections



On 11/4/06, Jeff VR <jffvnrkl@xxxxxxxxx> wrote:
Hello,
I'm trying to create a gschem symbol for one of my modules.  It's
connecting primarily with a surface mount connector that receives the
pins from the module.  The pins from the module will touch the pcb
before the module is fully down on the connector so I added holes to
allow them to pass through.  To make the board a little cheaper I made
the holes pins int the footprint and I just as well connect the pin
hole to the appropriate pad so someday I could decide to leave off the
surface mount connector all together.

My visible schematic pins get assigned to pads of the footprint.  The
trick is I want to add the invisible pins that get associated with the
paired visible pin.  I know how to implicitly tie a pin to a net but
the netname(net?) for my explicit pins gets overridden when I run
gchem2pcb thus breaking my connection between my pad and pin.   This
is hard to explain let me try a visual.

I want to connect each of these pairs.  My footprint has 20 pads and
20 pins with the following numbering.  Again the primary objective is
to connect each pair within the symbol that represents this module and
only have 20 pins visible on the schematic.
Pad   Pin
1        21
2        22
3        23
4        24
5        25
6        26
7        27
...       ...
20      40

I tried assigning pin 1 the same netname as pin 21 but I think when I
convert the schematic to pcb it overrides that attribute with the
netname from the schematic thus breaking the connection in the symbol
between pin 1 and 21.

Of course I could just add the 20 extra explicit pins to my symbol and
then draw the nets on the schematic that connect each pair but this
seems like clutter that the tools will allow me to avoid if I just new
how to do it.

I am not quite sure of the question so I hope this helps.

You can have pins and pads in a footprint with the same the "pin number"
and they will connect. In the footprint below I overlay pads (on component and
solder side) with pins.

(* jcl *)

Element[0x0 "DIP-8-300" "" "" 0 0 -21000 -26500 0 100 0x0]
(
  Pad[-16500 -15000 -13500 -15000 6000 2000 8000 "" "1" 0x0800]
  Pad[-16500 -15000 -13500 -15000 6000 2000 8000 "" "1" 0x0880]
  Pin[-15000 -15000 6000 2000 8000 3500 "" "1" 0x01]
  Pad[-16500 -5000 -13500 -5000 6000 2000 8000 "" "2" 0x0800]
  Pad[-16500 -5000 -13500 -5000 6000 2000 8000 "" "2" 0x0880]
  Pin[-15000 -5000 6000 2000 8000 3500 "" "2" 0x01]
  Pad[-16500 5000 -13500 5000 6000 2000 8000 "" "3" 0x0800]
  Pad[-16500 5000 -13500 5000 6000 2000 8000 "" "3" 0x0880]
  Pin[-15000 5000 6000 2000 8000 3500 "" "3" 0x01]
  Pad[-16500 15000 -13500 15000 6000 2000 8000 "" "4" 0x0800]
  Pad[-16500 15000 -13500 15000 6000 2000 8000 "" "4" 0x0880]
  Pin[-15000 15000 6000 2000 8000 3500 "" "4" 0x01]
  Pad[13500 15000 16500 15000 6000 2000 8000 "" "5" 0x0800]
  Pad[13500 15000 16500 15000 6000 2000 8000 "" "5" 0x0880]
  Pin[15000 15000 6000 2000 8000 3500 "" "5" 0x01]
  Pad[13500 5000 16500 5000 6000 2000 8000 "" "6" 0x0800]
  Pad[13500 5000 16500 5000 6000 2000 8000 "" "6" 0x0880]
  Pin[15000 5000 6000 2000 8000 3500 "" "6" 0x01]
  Pad[13500 -5000 16500 -5000 6000 2000 8000 "" "7" 0x0800]
  Pad[13500 -5000 16500 -5000 6000 2000 8000 "" "7" 0x0880]
  Pin[15000 -5000 6000 2000 8000 3500 "" "7" 0x01]
  Pad[13500 -15000 16500 -15000 6000 2000 8000 "" "8" 0x0800]
  Pad[13500 -15000 16500 -15000 6000 2000 8000 "" "8" 0x0880]
  Pin[15000 -15000 6000 2000 8000 3500 "" "8" 0x01]
  ElementLine[-21000 -19500 -21000 19500 1000]
  ElementLine[-21000 19500 21000 19500 1000]
  ElementLine[21000 19500 21000 -19500 1000]
  ElementLine[21000 -19500 5250 -19500 1000]
  ElementLine[5250 -19500 0 -14250 1000]
  ElementLine[0 -14250 -5250 -19500 1000]
  ElementLine[-5250 -19500 -21000 -19500 1000]
)

--
http://www.luciani.org


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