Minimal overhead modification of iterative logic arrays for C-testability

The minimal modification of the basic cell of various iterative logic arrays to make them C-testable is investigated. The overhead is measured in terms of the number of additional columns and rows to be added in the flow table of the basic cell. One-dimensional unidirectional arrays without vertical outputs, one-dimensional bidirectional arrays with vertical outputs, and two-dimensional unidirectional arrays are considered. The overhead of the present approach is shown to be smaller than that of previous approaches. It is demonstrated that two extra columns and two extra rows are enough to make any arbitrary two-dimensional orthogonal unidirectional array C-testable