ID:15636 Input port <name> of atom "<name>" cannot be inverted

CAUSE: The specified atom has the specified input port that is inverted. However, the specified input port cannot be inverted. The inversion must be removed from the specified port.

ACTION: If you are using an EDA tool, contact the technical support for the EDA tool regarding this message. For further assistance contact Intel Technical Support by creating a Service Request at www.altera.com/mysupport.