Increasing Output Compaction in Presence of Unknowns Using an X-Canceling MISR with Deterministic Observation
Ritesh Garg, Richard Putman, Nur A. Touba · Proceedings - IEEE VLSI Test Symposium/Proceedings of the ... IEEE VLSI Test Symposium · 2008
Recently, an X-canceling MISR methodology was proposed in Touba (2007) which was based on providing very high probabilistic error coverage by canceling out X's in MISR signatures. This paper investigates a new methodology for using the X-canceling MISR architecture based on deterministically observing scan cells. The two main advantages of the proposed approach are (1) it can provide a higher amount of compaction, and (2) it is effective for larger percentages of X's in the output response. Also, this paper investigates a hybrid approach that combines X-masking with an X-canceling MISR. Experimental results indicate that significant amounts of output compression can be achieved with no loss of fault coverage.