Software-Based Self-Test of Embedded Microprocessors

Abstract

In the recent years, the usage of embedded microprocessors in complex SoCs has become common practice. Their test is often a challenging task, due to their complexity, to the strict constraints coming from the environment and the application, and to the typical SoC design paradigm, where cores (including microprocessors) are often provided by third parties, and thus must be seen as black boxes. An increasingly popular solution to this challenge is based on developing a suitable test program, forcing the processor to execute it, and then checking the produced results (Software-Based Self Test, or SBST). The SBST methodology is particularly suitable for being applied at the end of manufacturing and in the field as well, to detect the occurrence of faults caused by environmental stresses and intrinsic aging (e.g., negative bias temperature instability, hot carriers injection) in embedded systems. This chapter provides an overview of the main techniques proposed so far in the literature to effectively generate test programs, ranging from manual ad hoc techniques to automated and general ones. Some details about specific hardware modules that can be fruitfully included in a SoC to ease the test of the processor when the SBST technique is adopted are also provided.