Automatic error correction of tri-state circuits

Boolean equivalence checking is a well established approach for verifying combinational circuits and is on the verge of becoming an integrated part of the design cycle. Previously (1999), we have presented a method for performing automatic error correction in combinational circuits if equivalence checking fails. However like all other automatic error correction techniques proposed in the past, it cannot handle circuits containing tri-states. This is a restriction for practical applications since tri-states occur in many real-life circuits. In this paper we present two solutions how the rectification method can be extended to locate and rectify errors in tri-state circuits. This makes the method applicable to a much broader range of circuits.