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AR# 18127

8.1i XST - "Error: NGDBuild: 174 - Reference to library work not yet defined..."


Keywords: ISE, Project Navigator, XST, EDIF, netlist, cyclic, library, work, forward referencing

NGDBuild fails with the following error:

"Error: NGDBuild: 174 - Reference to library work not yet defined..."


This can happen if the project design is using cyclic library references (an element in the Work library uses a component from another library, while components in this other library reference components in the Work library).

NGDBuild fails because the EDIF netlist is written so that the Work library is referenced before it is defined.

XST has not yet been given the capability to handle cyclic library references. To work around this error, the design must be rewritten without the cyclical references or the user should use another synthesis that properly handles cyclic library references.
AR# 18127
Date Created 09/03/2007
Last Updated 01/06/2009
Status Archive
Type General Article