Design of Self-Dual Fault-Secure Combinational Circuits

The method of alternating inputs is an interesting combination of time- and hardware-redundancy for error detection of self-dual circuits. In this paper it is shown how a combinational self-dual circuit can be transformed into a self-dual fault-secure circuit. For 82% of the benchmark circuits the necessary average area overhead is only 8,81%. A selfdual circuit is called self-dual fault-secure it every error due to a single stuck-at fault is immediately detected. Faults are detected if, for alternating inputs, the outputs of the faulty circuit are not alternating

Concurrent Checking of Sequential Circuits by Alternating Inputs

In this paper we investigate how the method of alternating inputs can be applied for concurrent checking of sequential circuits. The state transition function and the output function of the sequential circuit are transformed into corresponding self-dual functions and the memory elements are duplicated. Alternating inputs are submitted to the primary inputs of the sequential circuit. The primary outputs are alternating as long as no error occurs. The error detection probabilities for errors due to single stuck-at faults of the combinational circuits, the memory elements and of the input lines are experimentally determined for benchmark circuits