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dbgAutoCellFunction and RC scale factors

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 Dear All,

I have two questions regarding Encounter v6.2:

1) I read somewhere that before starting to work on a design in Encounter I should do: set dbgAutoCellFunction 1

Does anyone know why is that? What does this function do?

2) Does anyone know where to find or how to calculate the Capacitance/Resistance Scale Factors that are needed for RC extraction? These are filled in the Avanced> RC Extraction tab of Design Import window.

 Thanks in advance,

 Alex

Parents

  • Hi Kari Thank you,

    I got hold Violations (for Reg2Reg paths) for my block as follows:

    @CTS:: -0.405ns,

    @POST_CTS_OPTIMIZATION: -0.3ns,

    @ROUTE: -0.45ns ,

    @POST_ROUTE_OPT: -0.5ns ,

    After I extracted spef and I correlate spef and detailed spef i derived new scaling factors(0.9 for both res and cap) by using Ostrich tool.With those new scaling factors how can i avoid hold violations for tha block.

    And Where to use those Scaling factors exactly? What tool will do exactly if I run with new scaling factors?Will it take different Ressistance and capacitance values while calculating delays??

    I use them as follows in config file::

    postroute_res=0.9;

    postroute_cap=0.9; 

    My Primary doubt was as iam moving from post_cts_opt to routing stage the hold should be improved right.Then what will be the reason for hold degradation for my block? Is the tool doing RC extraction with very pessimism before routing the design??

    2nd doubt::

    Can the design density crosses more than 100%?? 

     

Reply

  • Hi Kari Thank you,

    I got hold Violations (for Reg2Reg paths) for my block as follows:

    @CTS:: -0.405ns,

    @POST_CTS_OPTIMIZATION: -0.3ns,

    @ROUTE: -0.45ns ,

    @POST_ROUTE_OPT: -0.5ns ,

    After I extracted spef and I correlate spef and detailed spef i derived new scaling factors(0.9 for both res and cap) by using Ostrich tool.With those new scaling factors how can i avoid hold violations for tha block.

    And Where to use those Scaling factors exactly? What tool will do exactly if I run with new scaling factors?Will it take different Ressistance and capacitance values while calculating delays??

    I use them as follows in config file::

    postroute_res=0.9;

    postroute_cap=0.9; 

    My Primary doubt was as iam moving from post_cts_opt to routing stage the hold should be improved right.Then what will be the reason for hold degradation for my block? Is the tool doing RC extraction with very pessimism before routing the design??

    2nd doubt::

    Can the design density crosses more than 100%?? 

     

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