At the beginning of CPLD Fitter execution, an error occurs in the design, and an error message similar to one of the following is reported:
"ERROR:CPLDFitter - NGD2NDS failed. The NDS network is not created due to errors.
Fatal: NGD2NDS did not create a network.
Cpld - Design 'top' has no outputs."
This only appears in the flow engine log window, and not in any report files. The fitter report may issue the following error:
"ERROR:nd200 - Design 'name' has no outputs."
This error occurs because all logic was removed from the design. This is usually due to no input or output pad connections being present in the design. Synthesis tools typically have a global switch that defines whether input/output pads are automatically inserted into a design.
To locate this switch in XST, go to Synthesis Properties -> Xilinx Specific Options Tab -> Add I/O Buffers.