  The identification of safe faults (i.e., faults which are guaranteed not to
produce any failure) in an electronic system is a crucial step when analyzing
its dependability and its test plan development. Unfortunately, safe fault
identification is poorly supported by available EDA tools, and thus remains an
open problem. The complexity growth of modern systems used in safety-critical
applications further complicates their identification. In this article, we
identify some classes of safe faults within an embedded system based on a
pipelined processor. A new method for automating the safe fault identification
is also proposed. The safe faults belonging to each class are identified
resorting to Automatic Test Pattern Generation (ATPG) techniques. The proposed
methodology is applied to a sample system built around the OpenRisc1200 open
source processor.
