Application of genetically engineered finite-state-machine sequences to sequential circuit ATPG

New methods for fault-effect propagation and state justification that use finite-state-machine sequences are proposed for sequential circuit test generation. Distinguishing sequences are used to propagate the fault effects from the flip-flops to the primary outputs by distinguishing the faulty machine state from the fault-free machine state. Set, clear, and pseudoregister justification sequences are used for state justification via a combination of partial state justification solutions. Reengineering of existing finite-state machine sequences may be needed for specific target faults. Moreover, conflicts imposed by the use of multiple sequences may need to be resolved. Genetic-algorithmbased techniques are used to perform these tasks. Very high fault coverages have been obtained as a result of this technique.