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AR# 22569

8.1i ISE - When I implement a top level EDIF design, the following error occurs: "ERROR:NgdBuild:28 - Top-level input design file "top_cs.ngc" cannot be found or created"


General Description:

When I implement an EDIF design, the following messages occurs in the console:

"WARNING:NgdBuild:257 - Launcher: Could not find the file "/project/top_cs" with extension "ngc" in the search path. The filename extension will be ignored.

ERROR:NgdBuild:28 - Top-level input design file "top_cs.ngc" cannot be found or created. Please make sure the source file exists and is of a recognized netlist format (e.g., ngo, ngc, edif, edn, or edf)."


This error occurs when the module name in the EDIF file does not match the file name.


A top level EDN file named "top.edn," contains following first line:

(edif top_vhdl

note that the name is "top_vhdl" (which is different than "top").

When implementation is run, there is no "top_cs.ngc" but "top_vhdl.ngc" in my run directory.

To resolve this error, rename all instances of "top_vhdl" to "top" in the "top.edn" file.

Project Navigator is issuing the wrong command when the EDIF file name does not match the top-level module name in the file.

This issue is fixed in the latest 8.1i Service Pack, available at:

The first service pack containing the fix is 8.1i Service Pack 1.
AR# 22569
Date Created 09/04/2007
Last Updated 07/07/2010
Status Archive
Type General Article