Changes in embedded software and testing

Evolution of embedded software

As embedded systems evolve, they become smaller, more powerful, and increasingly multifunctional. Developers now demand higher performance, lower power consumption, and greater integration within embedded applications. To meet these needs, microcontroller units (MCUs) and microprocessor units (MPUs) have undergone significant advancements.

Since the first 4-bit Intel MCU was introduced in 1971, MCU performance has increased dramatically. Today, 32-bit and 64-bit Arm-based MCUs operate at speeds exceeding 1 GHz, a stark contrast to early MCUs running below 700 KHz. Likewise, memory capacity has expanded from a few bytes to several megabytes, enabling more complex software execution.

In the past, MCUs were primarily responsible for basic input/output (I/O) control. Now, they drive sophisticated applications such as image analysis, signal processing, and real-time communication protocols. MCUs have evolved from simple controllers into the central intelligence of modern digital devices.

However, this increase in complexity presents significant software development challenges. Embedded software today consists of millions of lines of code, performing multiple functions in real time. As complexity rises, so does the risk of undetected software defects, making early-stage quality management essential. If issues are identified later in development—or worse, after deployment—the cost of fixing them escalates exponentially.

Figure 1: The cost of troubleshooting at different development stages

To mitigate risks and ensure high-quality embedded software, rigorous testing must begin early in the development process.

The role of embedded software testing

Software testing in embedded development follows a structured approach based on the V-model, where testing phases progress through:

1. Unit testing – Verifying the smallest functional units of code.
2. Integration testing – Ensuring different components work together.
3. System testing – Evaluating the complete embedded system.
4. Acceptance testing – Final validation before deployment.

Figure 2: Systematic software testing – Rick D. Craig & Stefan P. Jaskiel

Testing methods: static vs. dynamic analysis

Embedded software testing typically falls into two categories:

• Static analysis – Examining source code, design documents, and dependencies without execution.
• Dynamic analysis – Running the software in a simulated or real environment to detect runtime errors.

For optimal defect detection, both static and dynamic testing should be employed throughout development.

Test design techniques

Test cases are typically designed using:

• Specification-based techniques (requirements-driven).
• Structure-based techniques (analyzing program flow).
• Experience-based techniques (leveraging past testing knowledge).

Among these, experience-based techniques are commonly used to address real-world constraints in embedded testing.

Challenges in embedded software testing

Unlike traditional software testing in native environments, embedded software testing in cross-development environments presents unique challenges.

Figure 3: Native development vs. cross-development environment

Unlike a PC, MCUs have limited processing power and memory, making traditional debugging tools difficult to implement. Some embedded devices lack the ability to inject test code or simulate behavior effectively.

Embedded development occurs in a different environment than the actual execution platform. While the software might work on a development PC, unexpected behaviors can arise when deployed on actual hardware, which is affected by:

• Hardware dependencies (e.g., clock speed, bus communication).
• Environmental factors (e.g., temperature, humidity, electromagnetic interference).
• Hidden hardware defects impacting software operation.

Unlike object-oriented languages like Java or C#, embedded software written in C and Assembly lacks clear unit separation, making traditional testing approaches more challenging.

Due to these limitations, embedded software testing requires a flexible approach that adapts to hardware constraints, real-world dependencies, and system integration challenges.

Improving software quality with an advanced IDE

The growing complexity of embedded software has driven significant advancements in integrated development environments (IDEs).

In the early 2000s, the primary focus was code optimization, minimizing memory footprint, and increasing execution speed. Tools like IAR Embedded Workbench concentrated on compiler efficiency to maximize performance.

However, as embedded software has become more complex, the focus has shifted toward software quality, validation, and verification. Industry standards such as MISRA, ISO 26262, and IEC 62304 now emphasize static and dynamic analysis to improve reliability and ensure compliance.

To meet these requirements, modern IDEs integrate automated testing tools that enable:

• Early detection of coding errors through static analysis.
• Runtime error identification using dynamic analysis.
• Seamless debugging with real-time performance monitoring.

IAR Embedded Workbench: a comprehensive solution

IAR Embedded Workbench is one of the most widely used IDEs for MCU firmware development. It combines:

• Compilers, linkers, and debuggers in one environment.
• Static analysis (IAR C-STAT) and dynamic analysis (IAR C-RUN) for early bug detection.
• Powerful debugging tools that allow real-time memory, stack, and execution flow analysis.

Figure 4: IAR Embedded Workbench – integrated software testing and debugging

By integrating static and dynamic testing, modern IDEs significantly reduce software defects and lower development costs.

Conclusion

As embedded systems grow in size and complexity, the risk of software defects increases. Testing is no longer an afterthought—it is a critical part of the development process. However, embedded software testing is uniquely challenging due to resource constraints, hardware dependencies, and structural limitations.

To minimize risk and reduce problem-solving costs, developers must adopt advanced IDEs with integrated testing capabilities. By identifying issues early through static and dynamic analysis, teams can improve software quality while ensuring compliance with industry standards.

Investing in the right tools and methodologies will not only enhance product reliability and stability but also provide a competitive advantage in the embedded industry.

What’s next?

Ensuring high-quality, safe, and secure embedded software requires the right tools and expertise. Whether you're working on software-defined vehicles (SDVs), industrial automation, medical devices, or other embedded applications, IAR is here to help.

Get in touch! Contact our experts at fae@iar.com for guidance on quality, safety, and security strategies in embedded development.

Want to learn more? Visit iar.com/contact to explore how IAR can support your software development journey.