Answers Database

CADENCE GXILINX: APR/PPR guide may not work on pre-Unified Concept designs translated by GXilinx


Record #225

Product Family:  Software

Product Line:  Cadence

Problem Title:
CADENCE GXILINX:  APR/PPR guide may not work on pre-Unified Concept
designs translated by GXilinx



Problem Description:
It may be impossible to use the APR or PPR guide options on pre-Unified
Concept designs translated by GXilinx if GXilinx is run with the option
"physical_nets" set to ON.

PROGRAM:  gxilinx

VERSION: all versions up to v4.4-p1

PLATFORM(s):  Sun, HP


L


Solution 1:

CAUSE:
Net names are randomly generated on each run of GXilinx when it is run
with the option, "physical_nets", set to ON.  When set to ON, the
"physical_nets" option tells GXILINX to ignore the names of all nets in the
Concept schematic and randomly generate its own name for the nets.
It can be enabled in a GXILINX.CMD file by adding the line,

		     physical_nets on;

		     or by specifying the option on the command line:

			   gxilinx physical_nets=on

Since the APR/PPR guide option relies on net names being preserved from
run to run, guide will not work, because most of the net names will never
match in output XNF files from different runs of GXilinx..

This is a known problem with GXilinx versions up to v4.4-p1.

The main reason for turning physical nets ON in GXilinx is to avoid the #
symbols GXilinx uses as a hierarchy separator in the net names it
generates when the physical_net option is OFF.	"#" symbols will cause
XBLOX to issue an error message and die because "#" is not a legal
symbol for LCA files.


SOLUTION:

If you need to preserve the same net names each time GXilinx is run,
and also need to run GXilinx, the workaround is to leave physical nets
OFF (the default setting) when running GXILINX, then use a script or
text editor to replace all the "#" symbols with "_" in the output XNF file.





End of Record #225