The role of Cortex-M
Arm’s Cortex-M CPUs deliver the features that are needed for MCUs in the automotive compute platforms of the future. Automotive partners – like
Elmos Semiconductor which plans to adopt a range of Cortex-M products in its next-generation of automotive MCUs – are choosing Cortex-M for their MCUs as the product range delivers a common architecture, functional safety, advanced security and a broad ecosystem of support.
A common architecture
Recent global supply limitations have impacted the automotive industry. In some cases, vehicles have been unable to ship due to the lack of availability of endpoint MCUs. With few options for alternative controllers, vehicles have been stockpiled awaiting the availability of these critical components. The deployment of a standardized MCU compute architecture assists in providing added flexibility to deploy alternative products to fill gaps in availability.
Through 30 years of working with automotive industry partners, Arm has a diverse and scalable portfolio of compute cores for a variety of automotive applications, from the high-performance central compute to power-efficient endpoint MCUs. This provides a common architecture that means designers and developers benefit from scalable hardware and software that can be used across these automotive applications, saving engineering time and costs. Looking ahead to new SDVs, having this common architecture will enable software development and deployment, and OTA updates.
Functional safety
Functional safety underpins safety critical applications in automotive systems, helping to minimize the risk to people and the environment by detecting and reporting faults that may result in hazardous conditions. Functional safety is increasingly important as new technologies like autonomous driving emerge, while also continuing to support already established safety critical needs. Its need also extends to other markets beyond automotive, such as industrial, aerospace and transportation.
The Cortex-M family brings safety capabilities across all performance points of embedded controllers, enabling Arm’s partners to develop safety critical systems that scale.
Cortex-M85,
Cortex-M55 and
Cortex-M23 have a multitude of safety features that partners can utilize to achieve their safety goals in an efficient way.
Support from a broad software ecosystem then provides a plethora of safety certified software and tools for safety critical developments built on Arm Cortex-M CPUs. These can be easily accessed by Arm’s partners and the wider developer community. Arm also provides native support for safety tools and software, such as
Arm’s functional safety run-time system (FuSa RTS),
Software Test Libraries and
Arm Compiler for Embedded.
Security
Like safety, there is a rising need for enhanced cybersecurity to guard against malicious software attacks that pose serious threats to passenger vehicles. A hack now pose significant safety concerns, particularly as levels of autonomy rise in vehicles. Security features are also needed to protect against unauthorized access to information.
Upstream’s 2022 Global Automotive Cybersecurity Report states that 87.7 percent of reported security incidents in 2020 and 2021 were caused by threats to vehicle data and code.
The attack surface has increased in connected SDVs, with security needing to be considered across the complete vehicle and not just the high-performance nodes. The protection of edge MCUs must be accounted for and, together with the rest of the vehicle, considered across the lifetime of the vehicle to include software updates.
At a processor level, this means being able to trust the code being executed and having security features to mitigate spurious software attacks. Cortex-M class CPUs are increasingly used to perform secure system management and boot management services in central and zonal compute architectures. Through the Armv8-M architecture,
TrustZone is introduced across the Cortex-M family. Cortex-M23 and
Cortex-M33 are the first processors to support the hardware enforced separation and security offered by TrustZone. This ensures system-wide security spanning software, CPUs, Interconnect, Memory and Peripherals.
Through the Armv8.1-M architecture, more enhanced security features have also been added. Cortex-M85 includes Pointer Authentication Code (PAC) and Branch Target Indicator (BTI). PAC and BTI help mitigate against return-orientated and jump-orientated software attacks. For more information, read Alan Mujumdar’s blog on the
Armv8.1-M PAC and BTI extension.
The Arm ecosystem
As SDVs continue to play a more prominent role in the automotive sector, Tier 1s, OEMs and developers are looking at ways to optimize time and costs for software development. The sheer scale of the Arm architecture – with more than 200 billion deployments to date – motivates providers of tools, operating systems and software libraries to add Arm support in their offerings, enabling cost-effective software development. For Cortex-M processors, Arm’s ecosystem partners offer a broad range of support for IDE, compilers, Debug and Trace tools and software. Arm also offers the
Common Microcontroller Software Interface Standard (CMSIS)that provides consistent and standardized software building blocks. All this means automotive developers can choose from a broad range of options to reduce their time-to-market and development risk.
Driving automotive growth
The compute requirements of new SDVs support the wider automotive industry’s continuing need for a multitude of MCUs in vehicle compute platforms, with “no controller left behind.” Cortex-M CPUs offer power efficient computing, scalability, safety features and security functionality to support this drive towards wider MCU adoption. Alongside the product capabilities, Arm has the world’s largest software ecosystem that provides wider support to deliver a seamless integration and developer experience. With Cortex-M based MCUs helping to drive the growth of new vehicles like SDVs, the future of the automotive sector will be one that is built on Arm.
www.arm.com
