Retiming for BIST-sequential circuits

Pseudoexhaustive BIST of sequential circuits consists of breaking all cycles in the circuit, partitioning the obtained acyclic circuit by placing some segmentation cells in the circuit, and balancing the partitioned circuit by introducing (or selecting in the scan path) additional flip-flops as delays in order to apply combinational TPG methods, In this paper, we present a new efficient method for pseudoexhaustive BIST. We first determine the flip-flops that cause the unbalanced structure of the acyclic circuit by using the peripheral retiming and, second, we use these flip-flops for the circuit partitioning. Thus, these flip-flops can be used for both partitioning and balancing problem of the circuit at the same time. We propose an algorithm for a partitioning problem which combines our idea with existing approaches