General Description: After setting up timing specifications in the FPGA Express Constraints Editor, FPGA Express 3.x may generate an NCF file with invalid syntax. The Translate stage of implementation (NGDBUILD) may then give an error similar to the following:
Checking timing specifications ... ERROR:TSDatabase:19 - Processing TIMESPEC definition "TS_0=FROM "nco1_N214" TO "PADS" 15000.000000 pS" on instance "en_top_lvl_TIMESPEC_NCF": No TNM, TPSYNC or user group named "nco1_N214" is defined.
This occurs because the FROM:TO timespec in the ncf file written out by FPGA Express is: TIMESPEC TS_0 = FROM "nco1_N214" TO "PADS" 15 ns ;
when it should be: TIMESPEC TS_0 = FROM "nco1/N214" TO "PADS" 15 ns ;
An underscore "_" is used as the hierarchy designator instead of a forward slash "/".
Place this constraint in the UCF file using the correct syntax.
If you choose to edit the NCF file rather than transferring the constraint to the UCF file, do not click on Implement from Foundation Project Manager since the constraint will be exported again from FPGA Express before implementation begins.