Low-cost software-based self-testing of RISC processor cores

Software self-testing of embedded processor cores which effectively partitions the testing effort between low-speed external equipment and internal processor resources, has been recently proposed as an alternative to classical hardware built-in set-test techniques over which it provides significant advantages. In this paper we present a low-cost software-based self-testing methodology for processor cores with the aim of producing compact test code sequences developed with a limited engineering effort and achieving a high fault coverage for the processor core. The objective of small test code sequences is directly related to the utilization of low-speed external testers since test time is primarily determined by the time required to download the test code to the processor memory at the tester's low frequency. Successful application of the methodology to a RISC processor core architecture with a 3-stage pipeline is demonstrated.