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 Black Boxes 

Last post Mon, Jul 18 2011 10:54 AM by croy. 1 replies.
Started by AMit Raj 14 Jul 2011 10:38 PM. Topic has 1 replies and 2828 views
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  • Thu, Jul 14 2011 10:38 PM

    • AMit Raj
    • Not Ranked
    • Joined on Thu, Jul 14 2011
    • Bangalore, Karnataka
    • Posts 6
    • Points 120
    Black Boxes Reply

    While running LEC i got may unreachable blackboxes, can anyone tell me how to remove these BlackBoxes..??

    • Post Points: 20
  • Mon, Jul 18 2011 10:54 AM

    • croy
    • Top 500 Contributor
    • Joined on Fri, Jul 11 2008
    • <?xml version="1.0" encoding="utf-16"?> <string>HOME, PA</string>
    • Posts 32
    • Points 385
    Re: Black Boxes Reply

    What do you mean by "remove"? Remove from the reporting or remove from the design?

     

    Unreachables are a problem only if unexpected. You can do "report gate -unreach" to see why a point is unreachable (no path to an output through any sort of logic, therefore it has no effect, therefore LEC doesn't map nor compare it).

     

    Typical unreachables:

    1) unused logic in RTL

    2) spare gates

    3) disable test logic

    4) clock-gating latches (after modeling with set flatten model gated_clock)

     

    • Post Points: 5
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Started by AMit Raj at 14 Jul 2011 10:38 PM. Topic has 1 replies.