AR# 515: SYNOPSYS FPGA COMPILER: Problems reading an XNF file back into Synopsys.
AR# 515
SYNOPSYS FPGA COMPILER: Problems reading an XNF file back into Synopsys.
Description
Synopsys issues errors when reading in a post place-and-route XNF file. It issues one or more messages such as:
Error: File 'count8/count8.xnf', Line 54 at or near 'N171': Cannot match this DFF to a set of pins. Is it specified correctly?. (XNFI-1)
Solution
This occurs when you try to read in an XNF file that has been translated from the placed and routed lca file by LCA2XNF. An XNF file generated by LCA2XNF cannot be read in by Synopsys.
In order to read in a back-annotated XNF in Synopsys, the following steps must be followed after place and route:
1) LCA2XNF design
2) XNF2VSS design (This will generate an .vxnf file and attach SCHNM attributes, which are needed for the Synopsys XNF reader, in the XNF file.)