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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

  • The first thing i noticed in sdf values between your 8.1 and 9.1 run is that their precision is different. 

     You can use write_sdf -prec to determine how much precision you want. If you want to compare 9.1 with 8.1, use write_sdf -prec 4 while writing sdf. 

    Secondly, it didn't look like you were getting corners interconnect delay in your 8.1 run. Something is not right, if you were expecting corner delays there. In your 9.1, you are getting corner delays, and the one with 0's might be just becuase of precision.  

    You have to create analysis view for MMMC analysis. But looks like your intent is to do just bcwc analysis.

    You said you wanted sdf for back annotated simulation. While doing back annotated simulation, do you run in all three corners?

Reply

  • The first thing i noticed in sdf values between your 8.1 and 9.1 run is that their precision is different. 

     You can use write_sdf -prec to determine how much precision you want. If you want to compare 9.1 with 8.1, use write_sdf -prec 4 while writing sdf. 

    Secondly, it didn't look like you were getting corners interconnect delay in your 8.1 run. Something is not right, if you were expecting corner delays there. In your 9.1, you are getting corner delays, and the one with 0's might be just becuase of precision.  

    You have to create analysis view for MMMC analysis. But looks like your intent is to do just bcwc analysis.

    You said you wanted sdf for back annotated simulation. While doing back annotated simulation, do you run in all three corners?

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