Diagnosis of interconnect faults in cluster-based FPGA architectures

Fault diagnosis has particular importance in the context of field programmable gate arrays (FPGAs) because faults can be avoided by reconfiguration at almost no real cost. Cluster-based FPGA architectures, in which several logic blocks are grouped together into a coarse-grained logic block, are rapidly becoming the architecture of choice for major FPGA manufacturers. The high density interconnect found within clusters greatly complicates the problem of FPGA diagnosis. We propose a technique for the testing and diagnosis of cluster-based FPGA architectures. We present a hierarchical approach to define a set of FPGA configurations in which each fault is detectable, and each fault pair is differentiable. The cornerstone of this work is the concise expression of the distinguishing conditions of each fault pair. Experimental results demonstrate that nearly 100% fault coverage and diagnostic resolution are achieved with a low number of test configurations.