Input and output encoding techniques for on-line error detection in combinational logic circuits

Presents techniques 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. An input encoding algorithm and an output encoding algorithm that ensure that every fault at the input will either produce single bit error or unidirectional multibit errors at the output are proposed. If there are no input faults which produce bidirectional error, no internal stuck-at fault will result in such an error irrespective of the way the circuit is implemented. The proposed techniques have been applied to MCNC benchmark circuits and the overhead is estimated.<>