A technique for designing bidirectional error-free combinational logic circuits

A technique is presented for designing arbitrary combinational circuits so that any single stuck-at fault will result in either single bit error or unidirectional multibit errors at the output. Once the outputs of a circuit are encoded, unconstrained multilevel optimization can be applied to the circuit. An algorithm that detects whether a fault at an input line might result in bidirectional errors at the output is given. An algorithm for building circuits such that any stuck-at fault at an input line will result in unidirectional errors at the outputs is also proposed