Addressing Real-time Application Requirements with RISC-V Extensions

The ARC-V RHX processor is designed for hard real-time applications where predictability is paramount. Key features include:

• Advanced Interrupt Handling: RHX features a low-latency interrupt architecture, allowing critical events to preempt ongoing tasks with minimal delay.
• Precise Timing Controls: The processor supports fine-grained scheduling and timing mechanisms, ensuring that tasks execute precisely when required.

These features make RHX ideal for applications such as engine control, braking systems, and airbag deployment, where microsecond-level response times are essential.

To further enhance real-time performance, the adoption of the Synopsys RTIA (Real-time Instruction Architecture) extensions is highly recommended. Synopsys RTIA extensions enhance the standard RISC-V AIA (Advanced Interrupt Architecture) to provide hardware-level optimizations that streamline context switching, improve interrupt handling, and support task isolation.

• Faster Context Switching: RTIA reduces the overhead associated with switching between tasks, allowing the processor to respond to critical events more quickly.
• Improved Interrupt Response: With prioritized and nested interrupt support, RTIA ensures that the most urgent events are handled first, maintaining system stability.
• Enhanced Task Isolation: By separating tasks at the hardware level, RTIA improves both safety and security, preventing faults in one subsystem from affecting others.

These enhancements are particularly valuable on devices running real-time operating systems (RTOS), where multiple safety-critical and non-safety tasks must coexist. By leveraging RTIA extensions, automotive designers can meet the most stringent timing requirements while simplifying software development. RTIA optimizes the way interrupts are managed, reducing the time required to detect, acknowledge, and service interrupts with minimal overhead and area impact.

Latency Impact

• Reduced Interrupt Latency: RTIA can cut interrupt response times by up to 50%, enabling faster reaction to safety-critical events such as obstacle detection or collision warnings.
• Consistent Performance: By minimizing context switch overhead, RTIA ensures that system behavior remains predictable, even under heavy load.

Area Impact

• Modest Silicon Footprint: While RTIA introduces additional hardware logic, its area impact is relatively small compared to the overall benefits. The incremental increase in silicon area is more than offset by the gains in latency reduction and system reliability.
• Efficient Resource Utilization: RTIA’s design focuses on maximizing performance per square millimeter, making it a cost-effective choice for automotive SoCs where space and power are at a premium.

Leveraging ARC-V RHX processors with RTIA extensions allows automotive designers to build systems that are both high-performing and resource-efficient, meeting the demands of next-generation vehicles.

To fully leverage the benefits of ARC-V processors and associated extensions, automotive engineers should consider the following best practices:

1. Prioritize Critical Tasks: Use hardware-supported task prioritization to ensure that safety-critical functions always receive top priority.
2. Isolate Safety and Non-Safety Tasks: Implement task isolation at both software and hardware levels to prevent interference between subsystems.
3. Utilize Built-In Diagnostic Features: Take advantage of processor diagnostics and monitoring tools to detect and address faults before they impact system performance.
4. Optimize for Latency: Configure RTIA and AIA settings to minimize latency, especially in time-sensitive applications.
5. Balance Performance and Area: Select processor configurations that provide the necessary performance without excessive silicon area or power consumption.

Real-time determinism is a foundational requirement in today’s automotive applications, underpinning the safety, reliability, and performance of critical systems. The ARC-V RHX processor, with supported real-time interrupt architecture (RTIA extensions), offers a comprehensive solution for achieving deterministic performance in even the most demanding environments.

By focusing on low latency, efficient resource utilization, and scalable architecture, these technologies empower automotive manufacturers to deliver innovative features while meeting rigorous safety standards. As vehicles become smarter and more connected, the importance of real-time determinism will only continue to grow, making advanced processor solutions essential for the future of mobility.