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 f ault effects from the flip-flops to the primary outputs by distinguish ing the faulty machine state from the fault-free machine state. Set, c lear, and pseudoregister justification sequences are used for state ju stification via a combination of partial state justification solutions . Reengineering of existing finite-state machine sequences may be need ed for specific target faults, Moreover, conflicts imposed by the use of multiple sequences may need to be resolved. Genetic-algorithm based techniques are used to perform these tasks. Very high fault coverages have been obtained as a result of this technique.