A Built-in Circuit for Self-Repairing Mesh-Connected Processor Arrays by Direct Spare Replacement

We present a self-repairing circuit for a mesh-connected processor array with faulty processing elements which are directly replaced by spare processing elements on two orthogonal lines at the edges of the array. First, the spare assignment problem is formalized as a matching problem in graph theory. Using the result, we present an algorithm for reconstructing the array in a convenient form for finding the matching by a logical circuit. Second, the logical circuit which exactly realizes the algorithm is given. The circuit can be embedded in a target processor array to reconstruct very quickly the array with faulty processing elements without the aid of a host computer. This implies that the proposed system is effective in enhancing especially the run-time reliability of a processor array.