Description

Originally, the core was tested using the evaluation license on hardware and the DOUT stopped after several hours as expected. The core was purchased and the full license installed.  

In ISE, the "regenerate core" option was used to regenerate the netlist. However, the DOUT still stopped after several hours.

Solution

To resolve this issue, it is necessary to delete the old XCO and start again from the beginning to recreate the netlist.