Answers Database
NC-VERILOG: How to back annotate the SDF file for timing simulation?
Record #947
Product Family: Software
Product Line: Cadence
Product Part: Verilog-XL
Product Version: 2.5
Problem Title:
NC-VERILOG: 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 simulation using
NC-Verilog?
Two methods to back annotate delay values from an SDF file:
o compiling the SDF file at elaboration-time
o compiling the SDF file with Ncsdfc.
The NC Verilog simulator reads only compiled SDF files. The SDF
source file is supplied as an argument in a $sdf_annotate task by
Ngd2ver.
Solution 1:
To compile the SDF file at elaboration-time, use the -autosdf option.
ncelab -autosdf <testfixture_name> glbl
The elaborator first determines if the $sdf_annotate argument is an
SDF file or a compiled file. If it determines that it is an SDF file, it
then looks for a corresponding compiled file (sdf_filename.X). If it
doesn't find a corresponding compiled file, the elaborator issues a
warning message and then spawns the Ncsdfc utility to automatically
compile the SDF file. If a compiled file exists, Ncsdfc checks to make
sure that the date of the compiled file is newer than the date of the
source file and that the version of the compiled file matches the version
of Ncsdfc. If either check fails, the SDF file is recompiled. Otherwise,
the compiled file is simply read.
When invoked by the elaborator, the ncsdfc utility generates a log file
called sdf_filename.log.
Solution 2:
To read the ASCII SDF file using the Ncsdfc utility.
SDF files must be with Ncsdfc to annotate the timing information
contained in the SDF file.
ncsdfc sdf_filename.sdf
Ncsdfc will create a file called sdf_filename.sdf.X. If a compiled
file exists, Ncsdfc checks to make sure that the date of the
compiled file is newer than the date of the source file and that
the version of the compiled file matches the version of Ncsdfc. If
either check fails, the SDF file is recompiled. Otherwise, the
compiled file is simply read.
End of Record #947 - Last Modified: 11/12/99 16:38 |
