On the Design of Easily Testable Iterative Systems of Combinational Cells

A design procedure is shown which allows the construction of one-dimensional iterative systems of combinational cells with good single stuck-at fault test complexity. Let S be a system where one of the M input words and two of the N states are defined for test purposes and the cells are realized as AND–EXOR normal form circuits, then S is testable with at most [log2(M x N) + 6] tests for all single faults and for any number of cells. A weaker restriction is shown, where no normal form realization is necessary, and which gives good testability for single or multiple stuck-at faults of the input/output and interconnection lines of cells.