How to choose between ARM and RISC-V for your next embedded systems project?

Below is an expert comparison of RISC‑V and ARM processors from an embedded systems engineering perspective, focusing on programmability, toolchains, and programming languages.


—

1. Architectural and Programmability Considerations

RISC‑V

Open and Modular Design:
RISC‑V is an open-source ISA that allows engineers to customize the processor by selecting only the necessary extensions (e.g., integer, floating-point, vector, and bit-manipulation units). This modularity is particularly attractive for niche embedded applications where resources are limited or where tailor-made features are beneficial.

Simplicity and Clean-Slate Design:
The simplicity of the base ISA (typically 32- or 64-bit) makes it easier for embedded engineers to understand and optimize code. This clean design can result in lower power consumption and reduced silicon area—critical factors in deeply embedded devices.

Customization vs. Standardization:
Although the open nature is a strength, it can also lead to fragmentation if different vendors choose varying subsets and custom extensions. This fragmentation might complicate portability if your software targets multiple RISC‑V implementations.


ARM

Proven and Mature Ecosystem:
ARM’s proprietary ISAs (e.g., ARM Cortex-M for microcontrollers, Cortex-A for higher performance embedded applications) have been refined over decades. This maturity translates into robust documentation and established best practices in the embedded community.

Rich Feature Set and Optimizations:
ARM architectures typically offer a wide range of built-in features—from low-power modes to advanced interrupt handling—tailored for embedded applications. The design balances performance with power efficiency, which is crucial for battery-powered devices.

Ecosystem Consistency:
ARM’s licensing model leads to a more standardized set of instructions across vendors, making it easier to write portable, optimized code across different ARM-based platforms.



—

2. Toolchains and Development Ecosystem

RISC‑V Toolchains

GNU and LLVM Support:
The GNU toolchain and LLVM have robust support for RISC‑V, which means you can compile C/C++ code and even Rust programs. However, some toolchain optimizations may still be catching up compared to the decades of refinement seen in ARM’s tools.

Open-Source Emphasis:
Many RISC‑V development environments and simulators are open source. This openness can be an advantage for academic research or projects where licensing fees must be minimized.

Ecosystem Growth:
Although the ecosystem is rapidly maturing—with growing support from companies like SiFive and various academic projects—the debugging and performance analysis tools are still not as widely available or as polished as those for ARM.


ARM Toolchains

Diverse Commercial Options:
ARM benefits from a wide array of mature toolchains, including GCC, Keil MDK, IAR Embedded Workbench, and ARM’s own DS-5 suite. These tools are highly optimized for ARM cores, often providing better performance tuning, advanced debugging capabilities, and integrated simulation/emulation environments.

Integrated Development Environments (IDEs):
The ARM ecosystem offers highly integrated IDEs that simplify project management, peripheral configuration, and real-time debugging, which is a strong advantage for industrial embedded systems where time-to-market and reliability are critical.

Vendor and Community Support:
With years of adoption in the industry, ARM’s toolchain ecosystem is backed by extensive vendor support, community forums, and a plethora of third-party libraries—making troubleshooting and optimization more straightforward.



—

3. Programming Languages and Software Support

Language Support on RISC‑V

C/C++ Dominance:
Like most embedded systems, C and C++ are the predominant languages on RISC‑V. The open ISA encourages contributions to compilers and toolchains, gradually improving optimization capabilities.

Emerging Support for Modern Languages:
As the RISC‑V ecosystem matures, support for languages like Rust is growing. Rust’s focus on memory safety without sacrificing performance is particularly appealing in embedded systems, and the community is actively developing RISC‑V targets.

Assembly and Custom Extensions:
The straightforward RISC‑V assembly language is often used for low-level optimizations and hardware interfacing. Its clean design makes it more approachable than some legacy, more complex ISAs.


Language Support on ARM

Wide Range of Language Support:
ARM processors are widely supported by almost every mainstream programming language used in embedded development. In addition to C/C++, ARM toolchains support assembly language programming with robust, vendor-specific optimizations.

Industrial and Safety-Critical Software:
For safety-critical applications, ARM’s long-standing presence means that languages like Ada or MISRA C (a subset of C with guidelines for safety-critical systems) are well supported through certified toolchains.

Modern and Scripting Languages:
There is also growing support for higher-level languages (including Rust, MicroPython, and even JavaScript variants in some cases) on ARM platforms, primarily due to the extensive development of frameworks and runtime environments by both commercial and open-source communities.



—

4. Conclusion

Programmability:
RISC‑V offers a customizable and transparent ISA that can be finely tuned for specific applications, but it may require additional effort to manage ecosystem variability. ARM, by contrast, provides a standardized, mature environment that minimizes integration headaches and accelerates development.

Toolchains:
ARM’s toolchains are more mature and feature-rich, offering comprehensive commercial support and integrated development environments that are ideal for industrial-grade embedded systems. RISC‑V’s open-source toolchains are rapidly evolving and offer significant flexibility, though they might lag slightly in terms of enterprise-level optimizations and support.

Programming Languages:
Both architectures support the core languages of embedded systems (C/C++ and assembly), but ARM’s ecosystem provides broader support for safety-critical and high-assurance languages, while RISC‑V is quickly catching up, especially in the burgeoning Rust community and other modern programming paradigms.


In summary, your choice between RISC‑V and ARM in an embedded systems context depends on the specific project requirements: if you need a proven, standardized, and extensively supported platform with advanced toolchain capabilities, ARM is the safe bet; if customization, cost efficiency, and open-source flexibility are paramount, RISC‑V presents a compelling alternative that is rapidly maturing.