The ARM Cortex-R82 is the latest high-performance real-time processor from ARM designed for safety-critical applications. It builds upon the successful Cortex-R family of processors and offers significant improvements in performance, power efficiency, and reliability compared to previous generations.
Overview
The Cortex-R82 is a 32-bit RISC processor optimized for real-time deterministic execution in embedded systems. It implements the ARMv8-R architecture and includes features focused on high performance, power efficiency, and functional safety.
Key features of the Cortex-R82 include:
- Up to 8 cores running at up to 2.5 GHz
- Out-of-order superscalar pipeline
- Tightly-coupled memory subsystem
- Hardware virtualization support
- Enhanced reliability, availability, and serviceability (RAS) capabilities
- Lock-step mode for fault tolerance
- ISO 26262 ASIL-D safety certification
The Cortex-R82 is designed to deliver real-time responsiveness and high performance for applications such as automotive ADAS, industrial automation, robotics, medical devices, and transportation systems.
Performance
The Cortex-R82 represents a major performance leap over previous Cortex-R generations. Each core is capable of dual-issue superscalar execution, allowing it to issue and retire up to two instructions per cycle. This helps to fully utilize the core’s execution resources.
The out-of-order pipeline enables instructions to be reordered and executed efficiently, further enhancing performance. Local registers help reduce unnecessary memory accesses and stalls.
Overall, ARM claims the Cortex-R82 can achieve up to 3x the performance of the previous Cortex-R52 generation. Clock speeds scale up to 2.5 GHz, 40% higher than prior generations.
The L1 instruction and data caches have also been enlarged compared to prior designs. This helps feed the high-performance cores while minimizing trips to slower main memory.
Power Efficiency
While adding more performance, ARM has also focused on improving power efficiency. The Cortex-R82 implements multiple techniques to limit power consumption:
- Clock gating – Unused circuitry can be powered down when idle
- Power domains – Separate power rails to shut off unused sections
- Dynamic voltage and frequency scaling – Scale voltage and clock speed based on workload
New power control registers allow very fine-grained tuning of power states. Performance can be calibrated to precisely match application requirements without wasting power.
The net result is up to a 35% power efficiency gain over prior generations. This allows more performance headroom within tight thermal constraints.
Safety and Reliability
For critical real-time systems, reliability and functional safety are paramount. The Cortex-R82 implements numerous features to enhance safety:
- Lock-step mode – Duplicate cores run identical code to detect faults
- ECC protection – Error correcting codes on memories and buses
- Parity and error detection – Hardware checks to detect data corruption
- Bus-level protections – Address range checking, bus traffic encryption
These capabilities allow the Cortex-R82 to achieve the highest ASIL D safety certification for automotive applications. The lock-step feature enables two cores to run identical software in parallel. If the results differ, the system can flag an error and take corrective action.
For less critical applications, lock-step mode can be disabled to regain higher performance and power efficiency.
Real-Time Capabilities
Real-time performance is critical in embedded systems. The Cortex-R82 implements architectural features to enable predictable real-time behavior:
- Deterministic pipelines – No out-of-order execution or speculative memory accesses
- Interrupt handling – Low interrupt latency and predictable prioritized hierarchies
- Timing control – Cycle counting and stall insertion instructions
- Tightly Coupled Memories – Low latency RAM accessible by all cores
Software can take advantage of these capabilities to guarantee tasks meet their deadlines even in complex multi-core configurations. The processor is ideal for hard real-time systems that cannot tolerate unpredictable delays.
Memory Subsystem
The Cortex-R82 features an enhanced memory subsystem to feed its high-performance cores. Key highlights include:
- Large 1MB shared L2 cache – Reduces trips to main memory
- Hardware prefetching – Lookahead to timely load data from memory
- Coherent L1 caches – Automatic cache synchronization between cores
- Tightly Coupled Memory – Low latency RAM for critical software
The large shared L2 cache allows cores to minimize accessing external DRAM. When external memory is needed, prefetching hides much of the latency. Cache coherency keeps shared data synchronized.
The Tightly Coupled Memories provide 32KB to 64KB of fast RAM for storing critical routines and stack data. This memory can be accessed in a single cycle, versus multiple cycles for DRAM.
Virtualization
The Cortex-R82 includes virtualization capabilities to allow complex systems to be partitioned into isolated environments. This is useful both for safety and security:
- Separate software stacks can run on isolated guest OSes
- Faults in one OS will not impact others
- Guest OSes can be assigned resources and priorities
- Secure and non-secure worlds kept apart
Software is protected from directly accessing hardware or memory spaces belonging to other guests. The hypervisor can enforce timing partitioning to guarantee real-time behavior.
Virtualization allows consolidating multiple systems onto a single multi-core SoC without compromising reliability.
Development Tools
ARM offers a full suite of development tools for the Cortex-R82 including:
- Compiler toolchains – GCC, LLVM
- Debuggers – ARM DS-5, Lauterbach, iSystem
- Real-time operating systems – FreeRTOS, AWS FreeRTOS, Azure RTOS
- Modeling – Fast Models, Cycle Models
- Safety documentation – Safety manuals, Artisan Safety Certification Kits
These tools enable companies to build and verify complex software stacks leveraging the capabilities of the Cortex-R82. The processor also supports industry standard interfaces such as AMBA AXI, ARM CoreSight debug, and multiple RTOS solutions.
Licensing and Availability
The Cortex-R82 design is available for licensing to ARM partners for inclusion in SoC products. Lead partners will have early access to the IP starting in 2022.
First commercial silicon based on the Cortex-R82 is expected to sample in 2023, with devices hitting production in 2024. The processor is aimed at advanced driver assistance systems, industrial control, robotics, medical devices, storage, and mission-critical server applications.
By providing a major leap in real-time performance paired with functional safety, the Cortex-R82 will enable the next generation of embedded and edge computing systems.
