Krasamo is one of the top firmware development companies in Dallas, Texas, with more than 15 years of experience in IoT development

In industrial and commercial applications, embedded systems are fundamental for controlling and monitoring equipment, machinery, and plant operations. The primary challenge in the industry today is integrating these systems into the Internet of Things (IoT), which is especially difficult when working with legacy equipment not originally designed for connectivity.

This evolution demands a higher level of engineering to meet a demanding set of criteria: minimized energy consumption, reliable connectivity, precise data processing, and robust security for systems deployed in open environments.

Successfully navigating these technical requirements is the domain of professional firmware development. It is the critical discipline that ensures IoT devices operate effectively, securely, and reliably.

At Krasamo, we have spent more than 15 years mastering this discipline. As a top firmware development company based in Dallas, Texas, we specialize in building the reliable, secure, and efficient firmware that powers the next generation of embedded and IoT devices. This guide serves as a fundamental overview of this essential field.

What Is Firmware?

Firmware is a type of software embedded into hardware devices responsible for controlling their operation and device-specific low-level functions. Firmware provides devices with the instructions to carry out functions such as network connectivity, screen control, and interactions with other hardware components. Firmware is typically stored in flash memory (non-volatile) or read-only memory (ROM) and written in a low-level language such as C, C++, Rust or Assembly.

Understanding Firmware Development for IoT

Firmware development is the process of programming and maintaining the software embedded into IoT devices to access and control the microcontroller’s resources (I/O, memory, timers, etc.).

Developing firmware for embedded systems is a specialized discipline. It requires a deep understanding of the underlying hardware architecture, as components are tightly coupled and demand precise control for reliable operation. This foundation is crucial for ensuring the device’s performance, reliability, and security.

Furthermore, the field is constantly evolving, driven by advances in hardware. The increased processing power of modern microcontrollers, for example, allows them to support more sophisticated software. This has two major impacts:

• On-Device Intelligence: Many modern MCUs are now powerful enough to run optimized artificial intelligence (AI) and machine learning (ML) models directly on the device. This capability, known as Edge AI or TinyML, allows for real-time data processing and decision-making without relying on the cloud.
• Architectural Flexibility: This power also makes it practical to implement more complex, layered software architectures. To manage this complexity and improve portability, modern firmware development involves creating essential elements like drivers, APIs, and Hardware Abstraction Layers (HALs), which enable code to be adapted for multiple hardware platforms with minimal modifications.

Consequently, today’s IoT developers need a broad skillset: expertise in low-level languages like C or Assembly, the ability to diagnose issues on hardware, and the knowledge to architect and implement these advanced, layered systems.

Firmware Architecture and Components

To fully utilize the capabilities of microcontrollers, it is critical to understand their firmware architecture and system components, including the CPU for executing firmware instructions, memory types, sizes, and I/O protocols such as UART, USART, SPI, ADC, PWM that are used to connect sensors and actuators.

An organized firmware architecture defines the relationship between components and their environment, providing a foundation for software implementation. Developers can identify dependencies and interactions and typically divide firmware development into separate software layers, improving efficiency and maintainability in IoT development.

A firmware engineer can create an architecture diagram representing the system components and their relationships. Additionally, this can give an overview of the firmware system and software layers and their interaction with the hardware.

Microcontroller Processor

In the next paragraphs, we will discuss some of the critical components of the microcontroller system that are necessary to comprehend firmware development.

The central processing unit (CPU) is a microcontroller component responsible for executing instructions and controlling the microcontroller’s hardware. Modern microcontrollers can be typically found with 8, 16 or 32 bits CPUs, optimized for low power consumption and if real-time performance is needed, an RTOS can be integrated.

Focus on Low-Power Design: This optimization for low power is a critical discipline for any battery-operated device. It involves a range of specialized hardware choices and software techniques that go beyond standard firmware development. You can explore these strategies in our detailed guide to designing low-power embedded systems.

The processor, or CPU, contains a control unit, an arithmetic logic unit, and a set of registers. It connects to peripherals and memory, from which it fetches instructions. The processor then decodes and executes these instructions to control the system. In an embedded application, this means managing Input/Output operations to perform specific tasks, such as controlling a motor or collecting data from sensors.

Memory

ROM (Read-Only Memory) is non-volatile, meaning its contents are retained after the device turns off. ROM memory is usually where the microcontroller’s firmware is programmed and stored at the factory, and it cannot be altered.

Flash memory is non-volatile, yet it can be erased and reprogrammed. It is typically used for storing the main program code and data that may need updating, such as an operating system or configuration settings.

Another type of non-volatile memory is the EEPROM memory (Electrically Erasable Programmable Read-Only Memory) that can be erased and reprogrammed electrically, typically for applications where data changes frequently.

Random access memory (RAM) is used to temporarily store data that needs to be accessed while the microcontroller is running. It is fast, but volatile, meaning data is deleted after the device turns off.

I/O Peripheral

I/O peripherals are the hardware components that connect a microcontroller to the external world, allowing it to sense and control its environment. The microcontroller interacts with them by sending and receiving data using specific protocols over its I/O interfaces. While most peripherals involve bidirectional communication for control and data transfer, they are best understood by their primary function: either as an input device for receiving data or an output device for sending data and controlling actions. 

Input peripherals are used to receive data from the outside world. These include:

• Analog-to-Digital Converters (ADCs): Convert analog signals from sensors (like temperature or pressure) into digital signals that the microcontroller can process.
• Sensors: Directly provide data on environmental conditions.
• Timers and Counters: Used for precise timing and event counting.

Output peripherals allow the microcontroller to send data and control physical devices. These include:

• Digital-to-Analog Converters (DACs): Convert the microcontroller’s digital signals into analog signals to control actuators like motors or audio speakers.
• Actuators: Motors, relays, and servos that perform physical actions.
• Visual Indicators: LEDs, screens, and displays.

Interfaces

To communicate with other devices in the system—such as sensors, actuators, and other microcontrollers—an embedded system relies on communication interfaces. These are typically implemented using standard serial protocols like I2C, SPI, and UART, as well as other proprietary or standard interfaces. Because these protocols govern all external communication, expertise in designing and implementing them is essential for creating efficient and reliable firmware.

Modular Firmware: Benefits and Strategies

A modular structure can bring significant advantages to embedded firmware projects. By developing a flexible firmware architecture that is segmented in modules, functionality can be separated into independent modules with minimum dependencies and high cohesion.

Furthermore, this approach enables the modules to be used in new applications, making it a versatile solution.

Separating the application and low-level code boundaries is recommended to improve the scalability and maintainability of the device firmware. This separation allows for creating clear interfaces and function prototypes specific to each module, enabling them to perform their intended functions efficiently.

An architecture based on layers can hide the implementation details from other firmware layers and provide an interface with specifications for accessing hardware functions. A hardware abstraction layer (HAL) is a specific API designed with higher-level function calls to facilitate interaction with hardware.

While a deep dive into architectural patterns is a broad subject, the core principle is to always select the architecture that reliably meets your project’s needs.

Firmware Programming

Firmware programming creates a set of instructions that a microcontroller follows to coordinate its internal components and achieve the desired functionality of a device; therefore, it is critical to promote the security and reliability of the firmware code.

Firmware programmers with IoT skills and secure coding practices help protect from threats and attacks. They also follow firmware security practices such as encrypting data stored in the firmware, implementing access control, securing boot mechanisms, and using code signing, input validation, patch management, etc.

As mentioned, programming firmware in resource-constrained devices is challenging and requires optimization techniques.

When choosing a low-level programming language for the firmware, consider the specific needs of the project: target hardware, developer skill level, and the development environment. As a starting point, in the following paragraphs, we briefly describe the most important firmware programming languages.

• C Language. C is the most popular general language choice for developing firmware and is supported by manufacturers and tools. IoT developers must select a standard version of C language, such as the C99, ensuring safe constructs and useful features that support variable-length arrays, designated initializers, and restrict keywords. However, C language produces highly optimized code, requires memory management, and has less abstractions than C++.
• C++ Language. C++ is a low-level language, an extension of the C programming language that is used for programming complex systems, including portability across hardware platforms, providing direct access to hardware components and advanced concepts such as pointers, structs, memory management, etc. In addition, C++ supports object orientation; it is harder to optimize but gives the developer a higher level of abstraction.
• Assembly. Assembly is a programming language specific to processor architectures such as ARM, X86, and RISC-V with low-level instruction set and limited power and memory. It is a highly efficient program that controls hardware resources and enables code execution with low overhead. It isn’t a common choice to create a firmware codebase due to the almost inexistent abstraction, but if firmware speed and optimization is the main goal, it can be a good choice.
• Rust. Rust is a programming language that provides features for memory security and memory safety. It is a flexible firmware programming language that offers low-level access to resources and cross-platform compatibility. Rust creates an optimized executable and provides proper memory management, a high abstraction level, and fast running in embedded systems.
• Python. In the context of embedded systems, Python plays two distinct roles. On the host side, standard Python is an excellent tool for test automation, scripting, data analysis, and building user interfaces that communicate with a hardware device.

For writing the firmware itself, a specialized implementation called MicroPython (or CircuitPython) is used. MicroPython is a lean and efficient version of Python 3, optimized to run directly on microcontrollers. It dramatically accelerates development and prototyping due to its simplicity and extensive libraries. However, this ease of use comes at the cost of performance and higher memory consumption compared to low-level languages like C or Rust. This makes it an excellent choice for rapid prototyping, educational purposes, and projects where speed of development is more critical than raw execution speed.

IDEs Used in Firmware Development

Integrated development environments (IDEs) are essential to speed up firmware development; these provide the necessary tools, including a source code editor, version control system, compiler, assemblers, emulators, and linkers.

While general-purpose IDEs like Eclipse and VS Code (with PlatformIO) are popular, most professional development is done using IDEs that provide the tightest integration with the target hardware. These fall into two main categories:

Professional Third-Party IDEs

Tools like Keil MDK and IAR Embedded Workbench are industry standards known for their highly optimized compilers and broad support for different microcontrollers.

Manufacturer-Specific IDE

To provide the best possible support, most microcontroller vendors offer their own free IDEs tailored specifically for their hardware. For example:

• Silicon Labs: Simplicity Studio
• ST Microelectronics: STM32CubeIDE
• Texas Instruments: Code Composer Studio (CCS)
• NXP Semiconductors: MCUXpresso IDE and CodeWarrior

RTOS in Firmware Development

A Real-Time Operating System (RTOS) provides a framework for managing the complexity of modern embedded applications. Its core component is a scheduler that allows the system to run multiple software tasks concurrently, managing access to the CPU and other hardware resources. The primary benefit of an RTOS is determinism: it ensures that critical tasks are executed within predictable, fixed time constraints, which is essential for creating responsive and reliable devices.

It is essential to evaluate the capabilities of the RTOS to ensure it meets functional requirements such as response time, system reliability, and interrupt handling. Also, it must be capable of supporting the hardware platform and development tools to ensure it meets the performance requirements (responsiveness).

RTOSs are designed to meet the unique challenges of real-time systems, including the need for fast and reliable data transfer, interrupt handling, and synchronization of multiple tasks or processes, making them an essential component of many embedded systems and firmware applications.

Most RTOSs are available under open-source licenses, allowing customization to fit specific use case applications. This makes them versatile for deployment across various operations and devices.

Firmware Debugging

Firmware debugging is the essential process of identifying and fixing errors in code running on a microcontroller. Unlike purely software debugging, this requires a combination of specialized software and hardware tools.

The typical setup involves a software debugger (often integrated into an IDE) and a physical piece of hardware called a debug probe (e.g., a J-Link or ST-LINK). This probe connects the developer’s computer to the target device’s debug interface (like JTAG or SWD). This connection allows the developer to:

• Set breakpoints to halt code execution at specific lines.
• Step through the code line by line to observe its behavior.
• Inspect memory and CPU registers in real-time.
• Trace execution to analyze the program’s flow and timing.

In addition to hardware debugging, developers also use techniques like code reviews and logging (e.g., printing messages over a UART) to diagnose issues.

Firmware Testing: Ensuring Reliability and Safety

Firmware testing is one of the most critical stages in the development process, as a bug can cause device failure, safety risks, or costly recalls. Because firmware is so deeply integrated with physical hardware, it presents unique challenges that require a multi-layered testing strategy.

Key Testing Techniques

A comprehensive testing plan combines several techniques to validate the firmware at every level:

• Unit Testing: This is the most granular level of testing. Individual functions or modules of the code are tested in isolation to verify they perform exactly as expected. This helps catch bugs early, before they are integrated into the larger system.
• Integration Testing: Once individual units are verified, they are combined and tested to ensure they work together correctly. This stage focuses on validating the interfaces and data exchange between different software modules and hardware components.
• System Testing: The fully compiled firmware is loaded onto the target hardware to test the device as a complete system. This phase verifies that the product meets all functional and non-functional requirements, such as performance, timing, and power consumption.
• Hardware-in-the-Loop (HIL) Testing: For complex systems, HIL testing provides a bridge between simulation and the real world. The actual firmware runs on the target microcontroller, which is connected to a simulation that mimics the real-world environment and its various inputs and outputs. This allows for rigorous testing of scenarios that might be too dangerous or difficult to replicate physically.

Firmware Compiling and Linking

Linking firmware code is a process that combines object files, libraries, and dependencies into an executable image (firmware build) that is loaded onto the target platform.

The firmware is compiled into object files that are linked together with dependencies and contain machine-readable instructions to create a “firmware build” or “firmware binary” file (firmware image) to be loaded and executed by the hardware.

Linking combines the code and dependencies into a firmware image tailored to the project and the hardware platform.

Portable Firmware Development

Nowadays, clients consider building firmware code that can be reused and portable to other hardware, applications, and environments. Developing firmware should have a clean interface and detailed documentation that is easy to understand and helps to keep the firmware updated.

Ideally, engineers design firmware that can run on different MCUs and processor architectures with minor modifications.

As a firmware development company, Krasamo recommends building products on microcontrollers with defined generic interfaces that allow testing of new components, simplifying reusing code, and combining software components from various vendors.

Developing code in programming languages such as C or C++ in a standard accepted version using a well-defined implementation mechanism improves portability. Also, developing firmware code modularly or loosely coupled with few dependencies and cohesive elements can help execute specific functions on peripherals connected to an I/O interface.

A Krasamo firmware engineer is available to discuss how to create firmware and approach portability options adapted to your use case.

Embedded Software Development Services

When searching for a firmware company, it is critical to understand existing embedded architecture solutions for IoT and find a partner with firmware engineers who can technically influence your embedded system project.

Firmware engineers must be capable of designing a fully embedded system for IoT with different options based on the design objectives criteria.

In addition, firmware engineers must deeply understand the technical possibilities and limitations of every component in the system, from the microcontroller and memory to the sensors and actuators, to enable an advanced and reliable firmware design.

Krasamo has more than 15 years of experience developing firmware and helping clients with embedded projects. Krasamo offers:

1. A proven track record in embedded development (firmware programming, connectivity, hardware platforms, and development tools)
2. Firmware Customization and Optimization
3. Experience Developing Software for Real-time Systems
4. Testing and Debugging Services
5. Firmware Support and Maintenance
6. Troubleshooting and Debugging of Complex Issues

Krasamo IoT development Services

Applying these fundamentals to a real-world product requires strategic planning and deep technical expertise. At Krasamo, we provide end-to-end support to ensure your project is a success.

Our core services include:

• Custom Firmware and BSP Development
• System Architecture and Design
• IoT Connectivity and RTOS Integration
• Performance and Security Optimization
• Full Lifecycle Testing and Support

Every successful product begins with a solid strategy. To see how we can help you with architecture, component selection, and project planning, learn more about our IoT Consulting Services.