Optimizing Pseudo-Random Built-In Self-Testing of Fully Synchronous as well as Multisynchronous Networks-on-Chip

Most built-in self-test architectures use pseudo-random test pattern generators. However, whenever this technique has been applied to on-chip interconnection networks, overly large testing latencies have been reported. On the other hand, alternative approaches either suffer from large area penalties (like scan-based testing or the use of deterministic test patterns) or poor fault coverage in the control path (functional testing). Moreover, the recent proliferation of clock domains on a chip makes testing overly challenging. This manuscript presents the optimisation of a built-in self-testing framework based on pseudo-random test patterns to the microarchitecture of network-on-chip switches. As a result, fault coverage and testing latency approach those achievable with deterministic test patterns while materialising relevant area savings and enhanced flexibility. Finally, the authors implement the extension of the proposed testing methodology to multisynchronous systems, thus making it compliant with the relaxation of synchronisation assumptions in nanoscale designs.