Multiple identical pins, only one connection needed.

Chicken Farmer wrote on Tue, 13 August 2013 10:30

This is not a post about how to have multiple pins with the same name

(e.g. ground).

 

This is about having a package which has multiple pins with the same

name, only one of which needs to be connected. For a good example,

search for "smd tactile switch" on your favourite component vendor

website. A push button SMD tactile switch would have a very detailed

circiut symbol as:

 

 

 

 

1                                     

  3

o-------------------o

          |

          |

          o |

            |____

            |

          o |

          |

2         |         4

 

o-------------------o

 

and the land pattern will more or less match the circuit symbol. 

Naturally the actual circuit symbol would be more like:

 

      ___|___

A -o     o- B

 

It's easy enough to create a device where pin A is connected to pads

1,3

and pin B is connected to pads 2,4.

 

In practice only one of 1,3 and one of 2,4 needs to be connected (the

duplication is really for mechanical strength).

 

Is there any way to tell Eagle that this is the case so that before

routing it only has an air wire to one of the pins, and therefore

after

one pin is connected, it doesn't leave an air wire on the other pin?

 

 

On a very similar note, consider also a CR2032 battery holder which is

essentially a bent piece of metal with anchor points on both sides,

e.g.

 

http://uk.farnell.com/keystone/3002/battery-smd-retainer-20mm/dp/1650693

 

Likewise is there any way of telling the device that there is a

connection between the two terminals so that it doesn't try to connect

parts of the circuit connected to opposite sides with an air wire?

Hello,

I believe EAGLE does support this but it's not obvious.  When you are

connecting symbol pins to package pads/smds do the same thing you would do

with the one pin to multiple pads/smds (i.e. connect the first one and then

append the remaining).  So you should have a row to the right of the

Connect Dialog that looks like this:

G$1.GND   SH1, SH2, SH3, SH4

(names will be different obviously).

But the trick is the 2nd column in the list of made connections on the

right.  In the rows with appended pins you will see an icon.  If you mouse

over it will say "ALL".  That means that all of the connections must be

made.  But if you click on it then the icon changes slightly and a mouse

over will say "ANY".  That is what you want.

I haven't actually used this yet but I'm pretty sure that is supposed to do

what you are intending--if ANY of the connections is made then consider

that sufficient.

Let me know if that helps.

Cheers,

James.

--

James Morrison  ~~~  Stratford Digital

Specializing in CadSoft EAGLE

• Online Sales to North America

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--

Web access to CadSoft support forums at www.eaglecentral.ca.  Where the CadSoft EAGLE community meets.

SOLVED

CadSoft Guest wrote:

 

 

But the trick is the 2nd column in the list of made connections on the

right.  In the rows with appended pins you will see an icon.  If you mouse

over it will say "ALL".  That means that all of the connections must be

made.  But if you click on it then the icon changes slightly and a mouse

over will say "ANY".  That is what you want.

 

 

 

 

 

 

Let me know if that helps.

 

Cheers,

 

James.

--

James Morrison  ~~~  Stratford Digital

Thanks very much for the quick reply.

That did excactly what I want in both cases. The air wires have all gone.

A note to anyone else reading this thread, the change in icon is incredibly subtle when the pin in question is selected. It's almost invisible since the selection highlight is dark blue, and the change is the disappearance of a small black bar on the dark blue background. When a pin is not highlighted, the difference is sufficiently clear. Also, I used right click to toggle between the two started.

Regards

-Chicken