Characteristic States and Cooperative Game Based Search for Efficient Sequential ATPG and Design Validation

This paper introduces a new cooperative traversal on the partitioned finite-state-machine (FSM) space to generate test stimuli for both sequential test generation and design validation. The new features for this logic-simulation-based automatic test pattern generation (ATPG) include: (1) cooperative search that exploits orthogonality is performed on two global state partition sets; (2) feedback information is dynamically extracted from characteristic states (each characteristic state examines a subset of corner cases of the design) to prune away redundant search spaces; (3) different from dynamic partitioning, interactions between two global partition sets are emphasized in the proposed approach. The proposed cooperative search is similar to a cooperative two-player game, where each partition set presents the state space for a player. Experimental results show that test vectors generated by such a cooperative search can yield both higher coverage and up to 5 times reduction on test generation time