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Encounter 8.1 vs 9.1 sdf generation

MzQuarter

Hi,

I've used Encounter 8.1 for past projects to generate sdf back-annotation for simulation and it worked great. Now we've moved to Encounter 9.1, but the exact same 8.1 encounter project reloaded in 9.1 gives different results. First of all, the middle field ("typical", my guess) is no longer present, and when I load the sdf in a simulator the delays are all taken as 0 (no delays).  Second, the delays for interconnect are different, and quite often 0. Another difference I noticed is that in 8.1 the value triplets were always the same (which I thought odd), but not in encounter 9.1.

What am I missing? I'm almost sure it's just a setting, but I can't see where or how.

Thanks.

--------------------------------------------------------------------------------
Encounter 8.1:

(INTERCONNECT I_NCS U134/A (0.0037:0.0037:0.0037) (0.0037:0.0037:0.0037))
(INTERCONNECT I_SCLK Q_TRANSACTIONCOMPLETE_REG/CKN (0.0045:0.0045:0.0045) (0.0045:0.0045:0.0045))

Encounter 9.1:

(INTERCONNECT I_NCS U134/A  (0.003::0.004) (0.003::0.004))
(INTERCONNECT I_SCLK Q_TRANSACTIONCOMPLETE_REG/CKN  (0.000::0.000) (0.000::0.000))

Parents

  • If i understood correctly, you want to do mixed signal timing simulation with parasitic delay included. When you do extraction of your top level to generate SPEF, you could generate spef_typical, spef_best, spef_wst for different corners. Then before writing out sdf, you could just use  "set_analysis_view -setup best -hold best","spefIn spef_best'(look in cmd ref for full syntax), and then write_sdf . This will give sdf with interconnect delay for you best corner. Do the same thing for all 3 corners with corresponding spef and view. Then finally you have to combine all the sdf using "sdfCombine" to generate single sdf file with all three corners delay values populated.

    This may not be the most efficient way to do it. I will let other forum users to comment on the ways they are generating sdf.

Reply

  • If i understood correctly, you want to do mixed signal timing simulation with parasitic delay included. When you do extraction of your top level to generate SPEF, you could generate spef_typical, spef_best, spef_wst for different corners. Then before writing out sdf, you could just use  "set_analysis_view -setup best -hold best","spefIn spef_best'(look in cmd ref for full syntax), and then write_sdf . This will give sdf with interconnect delay for you best corner. Do the same thing for all 3 corners with corresponding spef and view. Then finally you have to combine all the sdf using "sdfCombine" to generate single sdf file with all three corners delay values populated.

    This may not be the most efficient way to do it. I will let other forum users to comment on the ways they are generating sdf.

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