A Heuristic Test-Pattern Generator for Programmable Logic Arrays

This paper describes a heuristic method for generating test patternsfor Programmable Logic Arrays (PLAs). Exploiting the regular structure of PLAs, both random and deterministic test-pattern generation techniques are combined to achieve coverage o f crosspoint defects. Patterns to select or deselect product terms are generated through direct inspection of an array; test paths to an observable output are established by successive, rapidly converging assignments of primary input values. Results obtained with a PLII program implementation of the method are described; these results demonstrate that the method developed is both effective and computationally inexpensive.