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 SDF Generation Confusion 

Last post Wed, Nov 7 2012 8:48 AM by moogyd. 0 replies.
Started by moogyd 07 Nov 2012 08:48 AM. Topic has 0 replies and 843 views
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  • Wed, Nov 7 2012 8:48 AM

    • moogyd
    • Top 500 Contributor
    • Joined on Mon, Mar 22 2010
    • Posts 23
    • Points 385
    SDF Generation Confusion Reply

    Hi,

    I have been given some SDF that has been generated for min/max

    write_sdf ../SDF/func.sdf      -precision 6 -max_view func_worst  -min_view func_best

     When I look in the SDF file, I see:

        (CELL
        (CELLTYPE  "SDFFRX1")
        (INSTANCE  instname)
          (DELAY
        (ABSOLUTE
        (IOPATH RN Q  () (0.445556::1.320084))
        (IOPATH RN QN  (0.282808::0.854712) ())
        (IOPATH (posedge CK) Q  (0.555220::1.656612) (0.407100::1.234008))
        (IOPATH (posedge CK) QN  (0.245180::0.769608) (0.303232::0.970056))
        )
          )
          (TIMINGCHECK
        (WIDTH (negedge RN) (::0.482700))
        (WIDTH (posedge CK) (::0.356600))
        (WIDTH (negedge CK) (::0.502200))
        (PERIOD (posedge CK) (::1.000000))
        (PERIOD (negedge CK) (::1.000000))
        (SETUPHOLD (posedge D) (posedge CK) (::0.351500) (-0.094300::))
        (SETUPHOLD (negedge D) (posedge CK) (::1.047800) (-0.297200::))
        (RECREM (posedge RN) (posedge CK) (::0.381600) (-0.049500::))
        (SETUPHOLD (posedge SE) (posedge CK) (::1.057100) (-0.088100::))
        (SETUPHOLD (negedge SE) (posedge CK) (::0.964600) (-0.146400::))
        (SETUPHOLD (posedge SI) (posedge CK) (::0.389800) (-0.107100::))
        (SETUPHOLD (negedge SI) (posedge CK) (::1.007200) (-0.292000::))
          )
      )

    i.e. The MIN/MAX triplets are present for the IOPATHS, but for SETUPHOLD I see only max for setup and min for hold.

    I think that this is giving problems in post layout gate level simulation (ncsim) where I use TOOL_CONTROL and +maxdelays. In this case, when I run a max simulation, no hold value will be annotated, so I see timing issues (since actual hold time is negative).

     I hope someone understands what I'm talking about ;-)

    Can anyone provide a solution.

    Thanks,

    Steven

    • Post Points: 5
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Started by moogyd at 07 Nov 2012 08:48 AM. Topic has 0 replies.