7 easy-to-use and long-lasting tips for embedded system development

Becoming a professional embedded systems developer is no easy task. It requires a deep understanding of every bit and byte of the system, as well as the discipline to ensure reliability in even the most challenging environments. There are many techniques that can be used to build highly dependable embedded systems, from well-structured development cycles to rigorous testing and validation. In this article, I’ll share seven practical and long-lasting tips that will help you create more robust and reliable embedded systems—while also detecting and handling anomalies when they occur.

Tip 1 – Fill the ROM with a known value

Many developers assume that their code will run flawlessly without any interference. However, microcontrollers can sometimes jump out of their intended application space and execute unintended code, which can lead to unpredictable behavior. This might happen due to a buffer overflow, a corrupted pointer, or a hardware fault. If the memory isn’t initialized, it may contain random values—making it hard to trace the root cause of the problem.

To mitigate this risk, one effective approach is to fill unused ROM sections with a known pattern using the FILL command. This not only helps detect unexpected execution but also allows the system to trigger an interrupt service routine (ISR) if it encounters invalid code. This gives the system a chance to log the error and take corrective action before it becomes critical.

Tip 2 – Check the application’s CRC

One of the great advantages of embedded development is the ability to automatically generate checksums like CRC. These can be used to verify the integrity of the application during startup or even periodically during runtime. While many systems only check the CRC at boot, doing so at regular intervals ensures that the application hasn’t been corrupted over time—especially in harsh environments where flash memory might be subject to errors or accidental writes.

Tip 3 – Perform a RAM check at startup

Hardware failures are inevitable, and checking the integrity of RAM at boot is a crucial step in ensuring system reliability. A simple RAM test involves writing a known pattern to memory and then reading it back to verify correctness. This helps catch early signs of hardware failure, such as faulty memory chips or electrical noise, which could otherwise go unnoticed and lead to system crashes.

Tip 4 – Use a stack monitor

The stack is often overlooked, yet it plays a vital role in system stability. If the stack grows beyond its allocated size, it can overwrite adjacent memory, leading to unpredictable behavior. A stack monitor can help by placing a known pattern between the stack and other memory regions. If the pattern changes, it indicates that the stack is overflowing, allowing the system to log the event and potentially recover gracefully.

Tip 5 – Leverage the Memory Protection Unit (MPU)

MPUs are becoming more common in modern microcontrollers and offer a powerful way to protect memory regions from unauthorized access. By isolating tasks and restricting memory access, MPUs can prevent one faulty process from crashing the entire system. Make sure to enable and configure your MPU properly—it can significantly improve system robustness.

Tip 6 – Build a strong watchdog system

A watchdog timer is essential for ensuring that the system recovers from unexpected failures. It should be independent of the main program logic and reset the system if it detects a failure. Advanced setups can include external watchdogs or task-based health checks, ensuring that each component is functioning as expected.

Tip 7 – Avoid dynamic memory allocation

While dynamic memory allocation (like malloc/free) is convenient in general-purpose systems, it can be risky in resource-constrained embedded environments. It can lead to memory leaks, fragmentation, and unpredictable behavior. Instead, consider using static memory allocation, where memory is pre-allocated and managed throughout the system’s lifecycle. This reduces the risk of runtime errors and makes debugging easier.

In conclusion, building reliable embedded systems requires careful planning, disciplined coding, and a solid understanding of hardware and software interactions. By implementing these seven strategies, you can significantly improve the stability and longevity of your embedded applications. Whether you're working on a small microcontroller or a complex real-time system, these practices will help you avoid common pitfalls and build systems that stand the test of time.