Monitoring BIST by covers

摘要

The authors show how to combine a conventional built-in self-testnmethod with a simple method for online error detection for combinationalncircuits. The output sequence of one or more components of the signaturenanalyzer is monitored, in test mode, by an error detection circuitnconsisting of a one-cover and a zero-cover. The cover circuits need tondetect only such faults that are masked by the signature analyzer.nBecause of a large number of don't-care conditions for the coverncircuits the hardware overhead is very low. All faults in the faultnmodel under consideration are detected either by the cover circuits or,ndue to an erroneous signature, by the signature analyzer