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 New board has missing nets 

Last post Thu, Feb 28 2013 1:01 AM by tmd63. 4 replies.
Started by tmd63 26 Feb 2013 04:17 AM. Topic has 4 replies and 725 views
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  • Tue, Feb 26 2013 4:17 AM

    • tmd63
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    New board has missing nets Reply

     I have a new design and the schematic has transferred to PCB.

    But when I look at the design, some of the nets have a boxand cross instead of a rubberband net. I have not set any plane layers yet.

    When I open the constraint manager, 'Properties' shows the nets but 'Electrical' does not.

    The impossible we do straight away. Miracles take a little longer.
    • Post Points: 20
  • Tue, Feb 26 2013 4:32 AM

    • oldmouldy
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    Re: New board has missing nets Reply
    It sounds like there has been some SI Setup, the "Box and Cross" will be down to assigned Voltages on the Nets, and the Nets will have been removed from Electrical because they are members of XNets, you can change the Options>Filter to uncheck XNets so that the Nets will be listed but, from a constraint standpoint, constraints will only be applicable to XNets. Remove the Voltage properties from nets and any assigned Signal Models on Comps to resume non-SI behaviour. You may need to change the schematic as well to prevent the properties from being re-imported during Logic Import.
    • Post Points: 20
  • Tue, Feb 26 2013 6:32 AM

    • tmd63
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    Re: New board has missing nets Reply

     I went into constraint manager and the missing nets do have voltages attached. But I could not find the options>filter in design entry HDL?

    These net are created by using the default power connections and these only allow a voltage. If I try to remove the voltage, it complains.

    The impossible we do straight away. Miracles take a little longer.
    • Post Points: 20
  • Wed, Feb 27 2013 1:17 PM

    • oldmouldy
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    Re: New board has missing nets Reply

    Clarification: In Constraint Manager, "you can change the Options>Filter to uncheck XNets so that the Nets will be listed" etc...There is also an Options>Filter check for "Nets of XNets", you could try that option.

    It sounds like your library includes Signal Model properties, certainly for discrete parts, as a consequence, you are going to get XNets created for any net with attached discretes with a high enough level license for the tools on Logic Import. There is a NO_XNET_CONNECTION property that can be attached to schematic parts to prevent XNets being created when discretes with signal model properties are used but this would need to be applied carefully in case some "real" XNets are not created as required.

    • Post Points: 20
  • Thu, Feb 28 2013 1:01 AM

    • tmd63
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    Re: New board has missing nets Reply

     OK Clarification.

    I open my constraint mananger and I see:

    File;Edit;Objects;Column;View;Analyze;Audit;Window;Help

    Objects>Filter does not show any XNets on the default view. But |If I switch to 'Electrical', 'Net', 'Routing' then the Object>Filter does show XNets.

     But switching the XNetticked or unticked does not change the view of net. They are still displaying a crossed box.

    I cannot change the schematic parts properties as this is a very large company and only the librarians have access to change these parts.

     

    The impossible we do straight away. Miracles take a little longer.
    • Post Points: 5
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Started by tmd63 at 26 Feb 2013 04:17 AM. Topic has 4 replies.