A functional-level testability measure for register-level circuits and its estimation
Estimation of circuit testability is an important issue when evaluating the circuit design. A testability measure indicates how easy or difficult it would be to generate tests for the circuit. STAFAN (Statistical Fault Analysis) is a well known gate-level testability analysis program which predicts the fault coverage of a digital circuit under the stuck-at fault model, without actually performing fault simulation. STAFAN offers speed advantage over other testability analysis programs such as SCOAP; further, it explicitly predicts the fault coverage for a given test set, unlike other testability measures which are harder to interpret. We show how a STAFAN-like testability analysis program can be constructed for circuits built out of register-level modules such as adders, multipliers, multiplexers, and busses. Our tool, which we call FSTAFAN, is useful in a testability-driven high-level synthesis environment. We have implemented FSTAFAN on a Sun/SPARC workstation and describe its performance on some register-level circuits.
testability measures level circuits module-external lines sensitization count stuck-at-faults