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Development System Reference Guide www.xilinx.com 165
PAR Syntax
R
• Signals that differ only by additional loads in the input design have the
corresponding pins routed according to the reference design in the guide file.
• Guide summary information in the PAR report describes the amount of logic from the
reference design that matches logic in the input design.
For detailed information about designing with PCI Cores, refer to the Xilinx PCI web page
at http://www.xilinx.com/systemio/pciexpress/index.htm
.
PA R S ynt ax
The following syntax places and routes your design:
par
[options] infile[.ncd] outfile [pcf_file[.pcf]]
options can be any number of the PAR options listed in “PAR Options.” They do not need
to be listed in any particular order. Separate multiple options with spaces.
infile is the design file you wish to place and route. The file must include a .ncd extension,
but you do not have to specify the .ncd extension on the command line.
outfile is the target design file that is written after PAR is finished. If the command options
you specify yield a single output design file, outfile has an extension of .ncd or .dir. A .ncd
extension generates an output file in NCD format, and the .dir extension directs PAR to
create a directory in which to place the output file (in NCD format). If the specified
command options yield more than one output design file, outfile must have an extension of
.dir. The multiple output files are placed in the directory with the .dir extension.
If the file or directory you specify already exists, an error messages appears and the
operation is not run. You can override this protection and automatically overwrite existing
files by using the –w option.
pcf_file is a Physical Constraints File (PCF). The file contains the constraints you entered
during design entry, constraints you added using the User Constraints File (UCF) and
constraints you added directly in the PCF file. If you do not enter the name of a PCF on the
command line and the current directory contains an existing PCF with the infile name and
a .pcf extension, PAR uses the existing PCF.
PAR Input Files
Input to PAR consists of the following files:
• NCD file—a mapped design file.
• PCF —an ASCII file containing constraints based on timing, physical placements, and
other attributes placed in a UCF or NCF file. A list of constraints is located in the
Constraints Guide. PAR supports all of the timing constraints described in the
Constraints Guide.
• Guide NCD file—an optional placed and routed NCD file you can use as a guide for
placing and routing the design.
PAR Output Files
Output from PAR consists of the following files:
• NCD file—a placed and routed design file (may contain placement and routing
information in varying degrees of completion).