Pseudo-exhaustive testing of sequential circuits for multiple stuck-at faults

Abstract

A Sequential circuit design is based on using mixed description of a behavior of a combinational part. The behavior is represented with a composition of ROBDDs and monotonous products. The design method provides fully delay testability of a combinational part of a sequential circuit. In this paper it is shown that the method also provides multiple stuck-at faults testability of a combinational part. The pseudo-exhaustive test consisting of two parts is developed. One part is used to test sub-circuits obtained by covering nodes of the proper ROBDDs by elementary circuits (Invert-AND-XOR circuits). It allows detecting multiple stuck-at faults at gate poles of elementary circuits evenly remote from the combinational part inputs. The second test part detects all multiple stuck-at faults at gate poles of the rest component of the combinational part. It is supposed that only one of these two components of a combinational part may be faulty. An estimation of the length of such test is given.