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 How To Find 1 Unrouted Net? 

Last post Fri, Jul 24 2009 1:09 AM by steve. 8 replies.
Started by melview1 22 Jul 2009 01:10 PM. Topic has 8 replies and 7168 views
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  • Wed, Jul 22 2009 1:10 PM

    • melview1
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    How To Find 1 Unrouted Net? Reply

    I am using OrCAD PCB Editor v16.2 and I have a design that has 1 unrouted net out of 366 nets.  I can't find where this unrouted net is.  I started by looking for the rats nest, but it doesn't show up.  I assume it is a very small disconnect that is difficult to find.  Does anyone know a way to find an unrouted net?  Maybe a menu option that can zoom me in to the net in question?  Any help would be appreciated.  Thanks.

     

     --Mark

    • Post Points: 20
  • Wed, Jul 22 2009 1:55 PM

    • Rik Lee
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    Re: How To Find 1 Unrouted Net? Reply

    Set the Color/Visibility to all invisible and then display all rats. You should see just the rat. You can also get an unconnected pins report and use the XY location listed to help find the missing connection. If the net has the VOLTAGE property applied you may want to remove that.

    • Post Points: 20
  • Wed, Jul 22 2009 2:04 PM

    • Nancie
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    Re: How To Find 1 Unrouted Net? Reply

    Maybe you can try this:

    Go in Tools --  Quick Report -- Unconnected Pins Report, and you will see the pins that are not connected. 

    • Post Points: 20
  • Wed, Jul 22 2009 3:28 PM

    • melview1
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    Re: How To Find 1 Unrouted Net? Reply

    Thanks for the tips guys, but none of them worked.  There's gotta be a way to have it zoom to the unrouted net or do an unrouted net report that gives you the coordinate of the net.  When I choose View-->Status, this is where I see "Unrouted nets:  1/366 0.3%"  In this status window, it allows you to click on all of the other items and get a report that gives you the location, but not the unrouted nets item.  Any other thoughts?

     

    --Mark

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  • Wed, Jul 22 2009 4:06 PM

    • redwire
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    Re: How To Find 1 Unrouted Net? Reply

    Try the quick report again and click on the coordinate in the report. Turn pad filling off, rats on, top and bottom only copper on.  It's there!

    You might have to try both sets of coordinates to find the end that's unrouted and make sure all nets with NO_RAT have that property deleted.

    Still can't find it? Send it to me as an attachment.

    • Post Points: 20
  • Wed, Jul 22 2009 4:59 PM

    • noahness
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    Re: How To Find 1 Unrouted Net? Reply

    What I do when I have a hard to find unrouted net (or anything whose coordinates are given in a report):

    Zoom way in (perhaps to point where a pad fills the screen) and then open the unrouted nets report. Clicking the coordinate in the report will then center the screen at that coordinate at the current zoom level.

    Hope this helps.

     

    -Noah

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  • Thu, Jul 23 2009 9:05 AM

    • melview1
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    Re: How To Find 1 Unrouted Net? Reply

    I figured it out.

    No matter what I did, I couldn't make a rats nest visible of the unrouted net in question.  Even doing the Unconnected Pins Report and clicking on the location didn't yield anything.  It showed me the location of the pin, but it appeared to be ok.  I probably had 20 lines in this report.  Pretty much all of my pin connections go off of the pad and immediately go to a via.  So what I did was to delete the connection between the pad and via and reroute it for all of the pins in the report.  None of them appeared to be incorrect or disconnected, but I did it anyway.  The report is now empty and the unrouted net is gone.

    This wasn't a problem with a previous revision of this layout.  The Unconnected Pins Report was empty.  I suspect something happened when I updated all of my discrete components to include a silkscreen change I made to the footprints.  Many of them "lost" their connection, like it was moved slightly off grid, due to a metric/english thing or something, but these showed the rats nest and were easily visible and easily fixable.  I had to reroute dozens of pins that had that problem.  However, it must have done something slightly different to the approximate 20 connections in the Unconnected Pins Report.  Many of which now had a small stub in the middle of the pad, like it was going from pad center to the nearest grid point, then to my trace.  When I rerouted it, this stub was removed.  Maybe OrCAD didn't like this stub for some reason (maybe there's a min trace length that it somehow violated?) and although it wasn't a complete disconnect to warrant a visible rats nest, it was enough to show up in the Status window as an Unrouted Net.

    Thanks for everyone's help.  Hopefully I was descriptive enough to help others.

     

    --Mark

    • Post Points: 20
  • Thu, Jul 23 2009 9:29 AM

    • mjmessinger
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    Re: How To Find 1 Unrouted Net? Reply

    I have one other suggestion of something to look for in this situation.  We've seen where a trace appears to connect properly to a pin but it isn't really connected.  Try using the slide tool to move the trace off of the pad.  If it is properly connected, the end of the CLine will be firmly rooted on the center of the pad.

    • Post Points: 20
  • Fri, Jul 24 2009 1:09 AM

    • steve
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    Re: How To Find 1 Unrouted Net? Reply

    If the units have been changed from metric to english or vice versa you could try Tools - Derive connectivity, check both the boxes and run. This will normally remove this type of "invisible connection". It's normally a process I would recommend if the units have been changed or if it's a translated design from another CAD package.

    • Post Points: 5
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Started by melview1 at 22 Jul 2009 01:10 PM. Topic has 8 replies.