Parallel pattern fast fault simulation for three-state circuits and bidirectional I/O

Industrial circuit designs commonly contain three-state elements, such as buses and drivers, transmission gates, and bidirectional I/O. A 5-valued fast fault simulation method and a 4-valued parallel pattern version that can handle these circuits are presented. Results demonstrate the effectiveness of the proposed methods in the presence of three-state elements, and show but a small performance degradation compared to 2- or 3-valued fault simulation.