Fault Classification of the Error Detection Logic in the Blade Resilient Template

Resilient architectures emerged as a promising solution to remove worst-case timing margins added due to process, voltage and temperature variation, improving system performance while reducing energy consumption. Asynchronous circuits can also improve energy efficiency and performance due to the absence of a global clock. A recently proposed circuit template, called Blade, leverages the advantages of both asynchronous and resilient techniques. However, Blade still presents challenges in terms of testing, which hinder its practical application. This paper evaluates the fault behavior of the Error Detection Logic (EDL) block of Blade with single stuck-at or propagation delay fault models. We propose a fault classification based on the effects observed in the overall circuit operation while in the presence of a fault. This classification shows the obtained fault coverage assuming three different testability scenarios and it also shows that a single fault can entirely disable an EDL, disabling its resilience. The proposed classification can be used in the future to improve the design for testability of resilient architectures.