My design contains several I/O that are unconnected. Since they are not used in the design, the CPLDFit tools optimize them out. I use the "Preserve Unused I/O" option, but these I/O continue to be optimized away. How do I keep these I/O from being removed from the design?
To work around this problem, place pin location constraints on these unused I/O. This, in combination with the "Preserve Unused I/O" option, will allow these I/O to be retained through implementation.
This application of the pin location constraints should not be required, and it will be corrected in a future software version.