Answers Database


VCS: How to back annotate the SDF file for timing simulation?


Record #6349

Product Family: Software

Product Line: ViewLogic

Product Part: VCS

Problem Title:
VCS: How to back annotate the SDF file for timing simulation?


Problem Description:
Urgency: Standard

General Description:
How to back annotate the SDF file for timing simulationusing VCS?

Two methods to back annotate delay values from an SDF file:

o compiling the SDF file at compile-time
o reading the ASCII SDF file at run-time.


Solution 1:

To compile the SDF file at compile-time, use the +compsdf option.

vcsi -R -f options.f +compsdf

VCS will default to an SDF file that has the same name as the top level
simulation netlist.   If you want to use a different SDF file, specify the SDF
file name after the +compsdf option.

This requires no table files on the command line, VCS automatically figures
out the required capabilities.



Solution 2:

To read the ASCII SDF file at run-time, the user must provide a
table file with the -P option.

Create a PLI table file (sdf.tab) that maps the $sdf_annotate
system task to the C function sdf_annotate_call. This file is
specified using the -P switch, eg:

vcs -P sdf.tab -y $XILINX/verilog/src/simprims +libext+.v time_sim.v

An entry in the sdf.tab file for your design might look like:

$sdf_annotate call=sdf_ annotate_ call acc+=tchk, mp, mipb:%CELL+




End of Record #6349 - Last Modified: 10/12/99 11:36

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