problem about $sdf_annotate and SDF type

[yyqonline]

hi, everyone

i am doing post-layout simulation with a SDF file generated by
PrimeTime command
"write_sdf"
and i back annotated the sdf file to my design using the system task
$sdf_annotate by:
$sdf_annotate("sdf_file_name", cell_instance) ;
and i found that ModelSim will not annotate the delay info to my
design, and the warning info is as follow
Warning: (vsim-SDF-3924) sdf_filename: Out of 11085 SDF
statements, 11085 had null values.
I have not succeeded in shooting this warning information about this
warning in ModelSim's manuals. And the Waveform generated shows that
there is no timing info except the specify in the verilog library.

At last, i found that if i annotate the sdf file by using the ModelSim
command
vsim -sdfmax
or
vsim -sdfmin
and ModelSim echoes the info showing that sdf info have been
annotated, and the waveform is ok.

Is anyone can show me something about the $sdf_annotate, esp. about
how ModelSim supporting this task.
And can anyone be kind enough to tell me about what the sdf type (typ,
max, min) mean?

Due to the network problem, i can not view many sites googled, so it
would be appreciated very much that anyone emailing me an emacs
verilog-mode file and other information.

Thanks a lot.

YQ Yang

 

[Ajeetha (www.noveldv.com)]

On Apr 3, 9:26 am, "yyqonline" <yyqonl...@gmail.com> wrote:

hi, everyone

i am doing post-layout simulation with a SDF file generated by
PrimeTime command
"write_sdf"
and i back annotated the sdf file to my design using the system task
$sdf_annotate by:
$sdf_annotate("sdf_file_name", cell_instance) ;
and i found that ModelSim will not annotate the delay info to my
design, and the warning info is as follow
Warning: (vsim-SDF-3924) sdf_filename: Out of 11085 SDF
statements, 11085 had null values.
I have not succeeded in shooting this warning information about this
warning in ModelSim's manuals. And the Waveform generated shows that
there is no timing info except the specify in the verilog library.

At last, i found that if i annotate the sdf file by using the ModelSim
command
vsim -sdfmax
or
vsim -sdfmin
and ModelSim echoes the info showing that sdf info have been
annotated, and the waveform is ok.

Is anyone can show me something about the $sdf_annotate, esp. about
how ModelSim supporting this task.
And can anyone be kind enough to tell me about what the sdf type (typ,
max, min) mean?

Due to the network problem, i can not view many sites googled, so it
would be appreciated very much that anyone emailing me an emacs
verilog-mode file and other information.

Thanks a lot.

YQ Yang

That would mean that your SDF file had empty entries for TYP delays.
If you look in PT manual for write_sdf, you should be able to fix
that. That was a good message from Modelsim to warn you BTW.

would be appreciated very much that anyone emailing me an emacs
verilog-mode file and other information.

I will send that to you, but going forward, getit from:

http://www.verilog-mode.com/

HTH
Ajeetha, CVC
www.noveldv.com