Block-Level Fault Model-Free Debug and Diagnosis in Digital Systems

The concept of fault model free diagnosis is combined with cause-effect analysis in digital systems represented as networks of functional blocks. We consider the diagnosis as a task to locate a faulty block in the network by using concise block level topological fault dictionaries. The dictionary does not need fault simulation and represents only the connectivity of blocks to observable checkpoints. We define the distance between the entries (codewords) in the dictionary, and make use of these distances to match the observed test responses to the entries of the dictionary. A measure is proposed for evaluating the block-level diagnosability of a given network which can be used for improving the diagnostic resolution. Experimental results provide the data which characterize the proposed measure and show the efficiency of using topological fault dictionaries.