High-level synthesis for orthogonal scan

Scan paths are commonly used in digital design to improve the testability of sequential circuits since a full scan path provides complete controllability and observability for every bistable element. A traditional scan path is implemented after the circuit has been designed, with little regard to the actual circuit function. High-level synthesis can exploit knowledge of the circuit function to synthesize a scannable circuit that has less area overhead than a circuit that has scan inserted after synthesis. In this paper, we discuss how synthesis algorithms that target orthogonal scan can result in final designs that are fully scanned and have as little as one-third the overhead of a traditional scan path.