Pioneering Automotive Safety with Arm Split, Lock, and Hybrid Modes

How does a car make split-second decisions such as switching between real-time traffic updates, adaptive braking, or lane assist correctional steering? There is a growing need for such techniques that allow cars to operate autonomously while managing dynamic, control, and safety challenges. This becomes more paramount amidst the growing demand for safer, smarter, and more connected vehicles and the increasing adoption of autonomous driving features. 

What is Arm Split, Lock, and Hybrid Mode?

Automotive systems like Advanced Driver Assistance Systems (ADAS), Automated Driving Systems (ADS), and In-vehicle Infotainment (IVI) need to process large volumes of data quickly all while maintaining multiple levels of safety integrity. Balancing these requirements is crucial for vehicles, particularly with ongoing computing challenges around performance, power, and area.

Designed to make tomorrow’s driving exhilarating, safe, and convenient, Arm’s Split, Lock, and Hybrid processing modes offer the versatility needed to support various automotive safety levels, further enabling automakers to develop vehicles that are safe, powerful, and adaptable.  

Arm’s Split, Lock, and Hybrid modes offer a comprehensive solution by enabling a single silicon design to operate flexibly in different modes tailored to specific safety and performance needs. This versatility allows automakers and Tier 1 suppliers to deploy the same hardware across a wide range of safety-critical automotive use cases. 

Split, Lock, and Hybrid Modes Use cases and examples

Split Mode: Maximizing Performance

Use case example: A vehicle’s IVI system handles many non-safety critical tasks, such as playing music, providing navigation directions, and managing cabin temperature, all while maintaining a seamless driver experience.  

How Split Mode Delivers: In Split mode, processor cores operate independently, delivering maximum performance when handling demanding applications. This enables high throughput in applications where rapid response and high data processing are critical, such as running multimedia, navigation, communication features, high-end graphics, and fast processing. This mode is perfect for scenarios where speed and efficiency are crucial, and safety isn’t the primary concern. 

Lock Mode: Uncompromising Safety: ASIL D 

Use case example: Various ADAS features are used when driving through dense fog on a busy highway. The vehicle will actively scan the environment, anticipate potential hazards, deploy traction control, and assist with steering and even brakes.  

The vehicle system processes obstruction data, calculates risks, and automatically steers the driver away from the hazard, or applies emergency braking, protecting them from a potential accident. It is imperative that these systems are fail-safe proof in life-threatening situations.  

How Lock Mode Ensures Safety: Lock mode is engineered for the most stringent safety-critical applications, such as ADAS L2+ features, where system failure could have life-threatening consequences. In this mode, processor cores operate in pairs, with the Arm DynamIQ Shared Unit (DSU) logic and memory operating in lockstep, ensuring a redundant operation that enables fail-safe execution. This redundancy is essential for systems requiring the highest safety standards, like ASIL D/SIL 3, which govern critical functions such as automatic braking and collision avoidance and acts as a countermeasure for security threat. 

Hybrid Mode: The Balanced Solution for ASIL B 

Use case example: Hybrid mode works harmoniously to optimize power consumption while maintaining essential safety measures, ensuring a smooth driving experience without compromising reliability or control. In moderate-risk scenarios, such as maintaining a safe distance from other vehicles using adaptive cruise control or managing energy efficiently, hybrid mode ensures that critical functions operate harmoniously to enhance your driving experience without unnecessary power consumption or safety compromises. 

How Hybrid Mode Balances: Hybrid mode is engineered with balanced performance and safety in mind. In this mode, cores operate independently, and the DSU logic operates in lockstep. This allows for some redundancy and safety features while maintaining a higher level of performance and efficiency compared to full lockstep. For mid-tier safety features such as lane departure warnings or energy management in electric vehicles (EVs) that only need ASIL B/SIL 2, Hybrid mode coupled with Software test libraries (STLs) provides a balance between Availability, safety, and performance.  

Paving the Way for Automotive Excellence

Arm’s Split, Lock, and Hybrid modes are more than just a technical term—they are the key to unlocking the future of automotive innovation. By offering flexible, high-performance, and safety-conscious solutions, Arm is the best choice of foundational platform to build the future of automotive with safe and reliable vehicles.