Extracting a Close-to-Minimum Multicycle Functional Broadside Test Set From a Functional Test Sequence

Abstract

Functional broadside tests avoid overtesting of delay faults that may occur with scan tests. Functional broadside tests can be extracted from a functional test sequence. This paper describes a procedure for extracting a close-to-minimum set of multicycle functional broadside tests from a functional test sequence. The procedure uses a modified sequential fault simulation process to collect information about detectable faults. This process indicates which faults must be detected by scan-out operations of multicycle tests, and which ones can be detected on primary outputs. The procedure uses a set-covering procedure to select a close-to-minimum set of clock cycles for scan-out operations. Every scan-out operation is complemented into a multicycle test. In addition, the procedure selects at most one test for faults that can be detected on the primary outputs. Experimental results are presented for benchmark circuits to demonstrate various features and extensions of the procedure.