Does freerouter route GND pins when perfomring autorouting

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Does freerouter route GND pins when perfomring autorouting

Postby TokTok » Wed May 28, 2014 9:49 am

Hi all,

I've been attempting to autoroute my .brd file using freerouter after creating the .sch and .brd files in cadsoft eagle.

I noticed that after creating the DSN file using the following .ulp file eagle2freerouter.ulp which I downloaded from the official Cadsoft downloads page. ( and then autorouting the DSN file in freerouter I noticed the ground pins seem not to be routed. I'm sure when using eagle autorouter the component ground pins get routed. All my ground pins as per my .brd file in eagle are connected with airwires which I expect to be routed in freerouter as the way eagle autorouter does it.

After posting my question on several forums online I came across an updated version of the ULP file which I've attached. As per the answer to my question (see this for forum link) it could be that I was using an old ULP file but even after using the updated file the GND pins on the DSN seem NOT to get routed.

Any ideas why or is the way freerouter performs its routing? Could it be an oversight on my part in terms of not understanding how freerouter performs routing?

I really would like to stick to using freerouter for my autorouting as it much better than eagle's default autorouter.

Below are download links to the respective files:
My .sch file -

My .brd file (routed using the .scr file generated from freerouter) -

My .dsn file (generated using the ULP file mentioned below) -

The ULP file I used -

I appreciate any suggestions/help.

Posts: 1
Joined: Wed May 28, 2014 9:04 am

Re: Does freerouter route GND pins when perfomring autorouting

Postby Elco » Wed May 28, 2014 11:30 am

[copy of my note in the Eagle support forum]

Just tested it, and it works OK. Since you have defined a "GND" polygon on both the top and the bottom layer over the whole board, the wiring signal "GND" is not routed, as it is already connected when loading the GND polygons.

If you delete the two GND polygon definitions in the DSN file (wiring is the last segment of the DSN file), you will see that the GND signal is properly routed.

Since signal polygons can breakup in routing, the eagle2freerouter converter allows you to specify the suppression of specific signal polygons (GND in this case) before Freerouter runs, forcing full routing of the GND signal. When loading the result into the Eagle BRD file, the polygons are added to get the copper back, but now you are sure that there are no orphan areas.

The converter has a lot of options to add to the Eagle functionality, look in the heading of the ULP under User modifiable parameters.

In this case, modify: string poly_drop = "";
into: string poly_drop = "GND";

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Joined: Wed Dec 21, 2011 4:15 pm

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