MCU addresses self-driving vehicle challenges

As carmakers endeavour to build more enjoyable, convenient and safe vehicles, driver assistance systems have rapidly become more sophisticated. In order to fully realise the autonomous vision of self-driving cars, Renesas believes that solutions are required across four key areas of automotive design; safety, security, sensors and networks. Renesas has developed the RH850/P1x-C series, which incorporates all four requirements on a single chip, to deliver an all-in-one solution for driver assistance systems.

Functional safety is essential to ensure the driver assistance system is operating normally and within safe parameters, and should a fault occur, to ensure that safety is not compromised. The RH850/P1x-C series includes a full complement of functions to support safety, and complies with ASIL D, the highest safety level stipulated in the ISO 26262 functional safety standard for road vehicles.

The RH850/P1x-C series is equipped with fault diagnostic functions, including two CPUs with identical configurations, operating in a lockstep system. ‘Error check and correct’ detects and corrects data errors affecting memory, such as flash memory and internal buses. The ‘built-in self-test’ function can detect faults in the various fault detection applications themselves, and the ‘error control module’ allows users to manage error signal inputs, based on circumstances, thereby helping to maintain system safety and reliability.

In the era of connected cars, in-vehicle, vehicle-to-vehicle, and vehicle-to-infrastructure networks are becoming mainstream, allowing systems to obtain information on road conditions and other factors that could impact the driving experience. Robust security measures are also required to ensure the systems are protected from unauthorised external access. The RH850/P1x-C series integrates a new hardware security module with a coprocessor supporting data encryption and random number generation to address safety-critical security requirements such as anti-tampering measures.

Vehicles use an increasing number of sensors, such as cameras and lasers, to collect information and respond to all types of driving conditions. This proliferation of sensors demands much larger software programmes and faster processing speeds. Renesas designed the RH850/P1x-C series with large memory capacity and a powerful CPU. The MCUs deliver the advanced functionality needed to support these requirements, offering up to 8MB Flash, up to 960kB global RAM, and operating speeds as fast as 240MHz.

Communication networks link driver assistance-related systems and implement cooperative control based on the data from the sensors. Communication functions of the RH850/P1x-C series include Ethernet, CAN, LIN, CSI and FlexRay, allowing the implementation of sensor fusion or complex control of chassis systems via a gateway function or vehicle network.

“The RH850/P1x-C are automotive safety MCUs that combine functional safety technology, security technology, and vehicle control network technology, which are the keys to realising safe vehicle control, on a single-chip. We anticipate that the series will become the world’s de facto standard for the sophisticated driver assistance systems of the future,” commented Ryuji Omura, Executive Vice President, Renesas. “With the safety MCUs, we hope to provide our customers with new added value by extending our lineup of vehicle safety MCUs to cover a wide range of vehicle segments, and at the same time building an ecosystem with a large number of partners to create a platform that will support the realisation of safer and more secure vehicles.”

Based on Renesas' 40nm process, the RH850/P1x-C series features the RH850/P1H-C and RH850/P1M-C group of MCUs. Samples of the RH850/P1x-C MCUs are scheduled to be available from February 2015. Mass production is scheduled to begin in September 2016 and is expected to reach a scale of 2m units per month in January 2020.