General Description: With FPGA Express 3.1 and earlier, when one writes out timing constraints, they are placed in the XNF file. If the timing specification becomes complex enough, these lines become exceedingly long and may violate the 2048 character limit. The following error will result during implementation:
ERROR:basxn:53 - Line number 30788: maximum field length exceeded
This issue has been resolved in FPGA Express 3.2 (Foundation 2.1i) and newer, as timing constraints are no longer written into the XNF. They are now placed in an NCF file.