The Spartan-3 "Single DCM" cores created within the CORE Generator tool become associated with the Spartan-3E/-3A "Single DCM_SP" Clocking Wizard Core once a project is closed and re-opened.
When the DCM-generated core is selected in the "Project IP" window in the CORE Generator interface, the "Single DCM_SP" product page is opened in the right-hand view of the CORE Generator interface. This page also displays the following messages:
This core was generated for a spartan3 ( xc3s400-5tq144 ) on 2010-09-20 at 21:53
This core is not supported by your chosen part.
This limits the ability to modify the previously generated core as the recustomization GUI cannot be opened from within the CORE Generator tool. It is also not possible to open the customization GUI by using the Manage Cores option from within Project Navigator.
The CORE Generator tool is incorrectly associating the previously generated Spartan-3 Single DCM Wizard with the Spartan-3E/-3A Single DCM_SP Clocking Wizard.
The core is correctly generated, and can still be used and implemented in a design in Project Navigator, or in a command line implementation flow.
From Project Navigator, the core can also be recustomized by double-clicking on the core in the design hierarchy, or selecting the core and choosing the recustomize core process in the Process window. After modifying the desired settings in the customization GUI for the Clocking Wizard, the core can be regenerated.
There is no work-around from within the CORE Generator interface to modify this core. In CORE Generator standalone mode, you must generate a new version of the Wizard from the beginning.