DISTRIBUTED MUTUAL INTER-UNIT TEST METHOD FOR D-DIMENSIONAL MESH-CONNECTED MULTIPROCESSORS WITH ROUND-ROBIN COLLISION RESOLUTION

A collision-free extension to the mutual inter-unit test methodology for d-dimensional VLSI multiprocessors is proposed to guarantee that any processor core is tested only by its neighboring node at a time and no special care needs to be taken to choose those moments when test actions should start. Collision resolution hardware based on the round-robin arbitration routine is discussed in detail. A parallel collision-resolution-aware mutual inter-unit test algorithm is formulated and diagrammed. The proposed approach has been shown to improve the testability of mesh-connected multiprocessors by increasing the probability of successful fault detection as compared with the distributed self-checking methodology. Further, the new approach drastically reduces extra connectivity in the multiprocessor with respect to known mutual inter-unit test methods and leads to more easily manufactured multiprocessor fabric. For example, in a 4-dimensional system, we need 55% less extra connections with our approach.