Simulation of non-classical Faults on the Gate Level - The Fault Simulator COMISM -

COMSIM is a fault simulator for combinational circuits which can efficiently handle various gate level fault models. Stuck-at faults, function conversions, bridging faults, transition faults as well as multiple faults of all types and faults with additional fault detection conditions, can be simulated in one pass. This offers a practical approach to solve the conflict between the accuracy of fault modeling, which usually requires a low level circuit description, and the desired performance of the simulation tools, which forbids the use of a low level description. In a preprocessing step which has to be performed only once for a given cell library, the effects of realistic faults are investigated for each gate type. These fault effects are mapped onto gate level faults and stored in a fault library. The specification of a corresponding gate level fault is almost always possible due to the wide variety of gate level fault models which can be simulated by COMSIM. Simulation results are given which demonstrate the practicability and the advantages of library-based fault modeling. The experimental results show that COMSIM can efficiently handle non-classical faults on the gate level.