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    static timing analysis

    there are two type of static timing analysis. pre STA and post STA. so ,how do this using sysnopsys tool?

    •   Alt15th April 2013, 12:24

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    Re: static timing analysis

    STA means static timing analysis, then you could analyze your design at any time of the flow. Generally the STA is only done as final step to check everything is fine.



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    Re: static timing analysis

    Pre STA is done by Design Compiler and is done before PnR..
    and Post STA is done by Prime Time and is done on Post layout netlist....

    But I can't understand that how we can do Pre STA as there is not any interconnection wire length information.



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    Re: static timing analysis

    Quote Originally Posted by maulin sheth View Post
    But I can't understand that how we can do Pre STA as there is not any interconnection wire length information.
    Therefore, the timing analysis will be more accurate after post STA.
    But we will try to estimate the interconnection delay before layout stage, said topographical mode in Design Compiler.
    This will reduce the gap between the pre STA and post STA.



    •   Alt16th April 2013, 04:45

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    Re: static timing analysis

    Quote Originally Posted by maulin sheth View Post
    Pre STA is done by Design Compiler and is done before PnR..
    and Post STA is done by Prime Time and is done on Post layout netlist....

    But I can't understand that how we can do Pre STA as there is not any interconnection wire length information.
    Wireload and interconnect are modelled in pre layout stage and .libs are used to compute the timing. Post layout the actual RC values are taken into account for accurate analysis.



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    Re: static timing analysis

    [QUOTE=jeevan.life;1222506]Wireload and interconnect are modelled in pre layout stage and .libs are used to compute the timing. Post layout the actual RC values are taken into account for accurate analysis.[/QUOTE

    what is the format for wire load model?as u said that it can be found in .lib file.so, will you please tell that how wire load model looks like?
    please gave me example.



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    Re: static timing analysis

    Wire load is a library file...and the format is .lib and also .db.... and .lib is ASCII format and .db is Binary format...
    It will include the wire load model...which contain the unit capacitance, fanout length etc....



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    Re: static timing analysis

    Quote Originally Posted by maulin sheth View Post
    Wire load is a library file...and the format is .lib and also .db.... and .lib is ASCII format and .db is Binary format...
    It will include the wire load model...which contain the unit capacitance, fanout length etc....
    will please explain how wire load model look like? i have seen .lib file but i unable to find this wlm.



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    Re: static timing analysis

    You can use "report_lib lib_name " command in dc_shell. It should report wire load model too.



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