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 Setting Clock Input Transition Value When Pin Defined at Instance Output 

Last post Wed, Jan 16 2013 8:08 AM by Kari. 1 replies.
Started by JAUB 16 Jan 2013 07:52 AM. Topic has 1 replies and 661 views
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  • Wed, Jan 16 2013 7:52 AM

    • JAUB
    • Not Ranked
    • Joined on Thu, Mar 22 2012
    • Posts 2
    • Points 25
    Setting Clock Input Transition Value When Pin Defined at Instance Output Reply

    Quick CTS question (EDI 10.1.3) . When the clock root is defined at the output , such as
     
    AutoCTSRootPoint   someInstanceName/Y
     
    How do I set the input transition value for the clock root ? 

    I cannot use RootInputTran in the clock spec file to specify the input transition at the clock root since the clock is not specified at an input pin/port.

    The clock report shows  that CTS used the default root input tran value of 1ps which is way to fast for this design (periods for clocks 47ns and 100ns). 

      I recall seeing something about a setting/variable to tell CTS to take the driving cell into account to avoid using the default, but I cannot locate it in the docs or through online search.

     Any suggestions ?

     Thank You,

     

    Jeff Aubert

     

    • Post Points: 20
  • Wed, Jan 16 2013 8:08 AM

    • Kari
    • Top 10 Contributor
    • Joined on Tue, Jul 15 2008
    • Cary, NC
    • Posts 684
    • Points 13,590
    Re: Setting Clock Input Transition Value When Pin Defined at Instance Output Reply

    Hi Jeff,

     Does this do what you want?

    set_global timing_clock_source_use_driving_cell true

    - Kari 

    • Post Points: 5
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Started by JAUB at 16 Jan 2013 07:52 AM. Topic has 1 replies.