In-Field NoC-Based SoC Testing with Distributed Test Vector Storage

The operational lifetimes of SoC and microprocessors face growing threats from technology scaling and increasing device temperature and power density. In-field (or on-line) testing of NoC-based SoC is an important technique in ensuring system integrity throughout this potentially shorter lifetime. Whether in-field testing is conducted concurrently with normal applications or executed in isolation, application intrusion must be minimized in order to maintain system availability. Specialized infrastructure IP have been proposed to manage on-line testing by scheduling tests and delivering test vectors to the various cores within the SoC from a centralized location. However, as the number of cores integrated into a single chip continues to increase, issuing test vectors from a centralized location is not a scalable solution. These increased distances that test vectors must travel have become a major concern for on-line testing because of its direct impact on application intrusion in terms of energy consumption, network load, and latency. In this paper, we apply a distributed storage technique to bound and minimize this distance, thereby minimizing network load, energy consumption, and test delivery latency across the entire network. Our experiments show that test delivery latency and energy consumption is reduced by approximately 90% for moderately sized NoC.