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 how do i set wire width and space for a particular net? 

Last post Thu, Sep 19 2013 11:14 AM by Kari. 7 replies.
Started by flyinmeteor 25 Mar 2010 04:28 AM. Topic has 7 replies and 2534 views
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  • Thu, Mar 25 2010 4:28 AM

    • flyinmeteor
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    • Joined on Thu, Nov 19 2009
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    how do i set wire width and space for a particular net? Reply

    see title

    • Post Points: 20
  • Thu, Mar 25 2010 10:47 PM

    • BobD
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    Re: how do i set wire width and space for a particular net? Reply

    If you're looking to set routing rules that NanoRoute will follow when doing detailed routing, have a look at:

    Route->NanoRoute->Set Attribute

    You can set additional spacing on any signal net, but if you want to route (for example) double-width wires you'd need to have or create a non-default rule in your technology LEF and then associate it with the nets you want routed double-width.

    Let me know if this isn't what you're looking for.

    Thanks,
    Bob

    • Post Points: 20
  • Mon, Jul 11 2011 10:43 AM

    • patrice06
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    Re: how do i set wire width and space for a particular net? Reply

    Hi Bob,

    Using non-default rule for creating wider wires for some specific case,  is well understood. Kari has also explained in a tutorial how to create those rules in a LEF file .

    But it is still obscure to me what we should do if we want to have "via arrays" on these wires. By default, it seems we get the default (single) via at each layer chnage.  How can we get the maximum possibe array of vias (like the special vias of the power/ground nets) ?

    Could you tell a bit more ?

    Thanks

    Patrice

    • Post Points: 20
  • Mon, Jul 11 2011 11:12 AM

    • BobD
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    Re: how do i set wire width and space for a particular net? Reply

    I think if the wire gets very wide you'd need to define via array generation rules by hand. If it's just multi-cut vias you're interested in you might try "generateLef -2cutVia" after defining the lef with the wider wires.

    -Bob

    • Post Points: 20
  • Tue, Jul 12 2011 6:01 AM

    • Kari
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    Re: how do i set wire width and space for a particular net? Reply

     Hi Patrice,

    You should be able to use the USEVIARULE statement in your NONDEFAULT rule to grab the via rule that you want to use, although if this isn't specified, it should be grabbing your default rules automatically. You can also try the MINCUTS statment in your nondefault rule; please check the LEF manual for details. Let us know if you get it working.

    - Kari

    • Post Points: 20
  • Fri, Mar 22 2013 1:36 PM

    • ttran0671
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    Re: how do i set wire width and space for a particular net? Reply

    Hi All,

         I'm currently having the same problem too.  I set Non-Default Rule to route wider width but it still insert single VIA for these Wider Width. I'm new to Encounter but I recall  IC Compiler is smart enough to do that when I specify the Custom Non-Default Rule with Double Widht/Double Cut ...Some like very strange......I hope Cadence AE can shed some lights on this.

    I did try  the %generateLef  -2CutVia    but getting an Error message and obviously it did not work.

     

    ** ERROR: (ENCRM-125): There are LEF files loaded. Skip generateLef utility. Please dont load any LEF files before invoking this utility.

     

    • Post Points: 35
  • Mon, Mar 25 2013 2:12 AM

    • patrice06
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    Re: how do i set wire width and space for a particular net? Reply

    Hi Ttran,

    First of all, I want to report that I was not able to get it to work, despite trying all the suggestions by Kari.

    But I would like to suggest another solution that  was in fact much more powerful for my case. I have used the mixed signal routing capability of Encounter. You can easily control many constraints.  I did that during the floorplan stage. Here is a pratical example to have this running easily:

    Encounter command:

    #special nets to probe pads
    routeMixedSignal -nets {pad_VPPD1 pad_VPPD2} -constraintFile MyConstraint.const

    MyConstraint.const  file (in the working directory):

    NETS
      WIDTH 8.000000
      SPACING 0.230000
      MAXRES 11.000000
      TAPERING
      MINCUT 16
      ROUTELAYERS M1:M3
         pad_VPPD1
    END NETS

    NETS
      WIDTH 15.000000
      SPACING 0.230000
      MAXRES 20.000000
      TAPERING
      MINCUT 64
      ROUTELAYERS M1:M3
         pad_VPPD2
    END NETS

    Please, try it, you will like it !

    Patrice

    • Post Points: 5
  • Thu, Sep 19 2013 11:14 AM

    • Kari
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    Re: how do i set wire width and space for a particular net? Reply

    TTran,

    Have a look at the generateVias command.

    - Kari 

    • Post Points: 5
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Started by flyinmeteor at 25 Mar 2010 04:28 AM. Topic has 7 replies.