The ISO 26262 ‘Road vehicles - Functional safety’ standard defines the entire safety life cycle for electronics and/or software in safety-related systems in vehicles weighing less than 3500kg. Included in this are specific recommendations for the mitigation of random hardware faults, including diagnostics and/or the specific implementation of hardware safety systems.
When an internal fault occurs during driving, the automotive computing system used in an autonomous vehicle must either stop the vehicle safely or continue driving safely. There are several approaches to hardware fault detection, such as logic duplication and self-testing. In these large-scale SoCs, the complexity of the functions and the high operating frequencies make it difficult to have duplicated logics for the overall functionality. Furthermore, to perform high-reliability self-testing in large-scale SoCs, it would be necessary to shut down functions required for self-driving and other operations for extended periods.
Renesas’ hardware fault detection technology is said to be based on a state-of-the-art self-testing mechanism to resolve these issues. This technology makes it possible, even in the large-scale SoCs used in self-driving systems, to meet the criteria such as diagnostic coverage, which is expected to be required for the ISO 26262 ASIL B standard for functional safety.
In addition, Renesas has developed a system to predict and suppress the momentary voltage droops caused by hardware faults, and to prevent these faults from occurring.
Renesas showcased this technology at the International Solid-State Circuits Conference in San Francisco. It demonstrated a board mounted with a SoC that implemented these technologies, showing the utility of these results by demonstrating continuous graphics display using both CPU and GPU operations while operating both the runtime self-test systems and systems for predicting hardware faults due to voltage droops.
