All ports are optional, with the exception that at least one input and one output clock are required. Availability of ports is controlled by user-selected parameters. For example, when Dynamic Reconfiguration is selected, only those ports related to Dynamic Reconfiguration are exposed. Any port that is not exposed is either tied off or connected to a signal labeled unused in the delivered source code.
IMPORTANT: Not all ports are available for all devices or primitives; for example, Dynamic Phase Shift is not available when Spread Spectrum is selected.