Electronic gadgets are controlled by microcontrollers, which are tiny computers. Since it is cheap, uses little power and is easy to connect into many devices, these find a lot of use in internet of things (IoT) applications. Central processing unit (CPU), random access memory (RAM) and input/output (I/O) components are all housed on a single chip. The I/O components allow the microcontroller to interact with its surroundings via sensors and tools, while the CPU executes instructions and the memory stores data and programs.
To develop an IoT device, one must communicate with a microcontroller using a programming language such as C or C++. An attached computer with a USB or serial port will be able to accomplish this. The microcontroller can later be programmed to control or communicate with other devices via the internet via Wi-Fi or cellular. There is a wide variety of microcontrollers to choose from, and they all have their own set of advantages and disadvantages. When it comes to IoT applications, some popular microcontrollers are ESP8266, Raspberry Pi and Arduino. The process of selecting an IoT device's microcontroller is covered in this article.
Popular types of microcontrollers for IoT
ARM Cortex-M Series:
- Raspberry Pi Pico: A powerful and affordable board with a dual-core ARM Cortex-M0+ processor.
- STM32F103C8T6: A popular microcontroller with a single-core ARM Cortex-M3 processor.
- NXP LPC824M101JDH: A low-power microcontroller with a single-core ARM Cortex-M0+ processor.
AVR microcontrollers:
- Arduino Uno: A widely used development board based on the ATmega328P microcontroller.
- ATmega328P: A versatile microcontroller with a single-core AVR architecture.
- ATtiny85: A small and low-power microcontroller with a single-core AVR architecture.
RISC-V microcontrollers:
- Allwinner R1: A powerful microcontroller with a quad-core RISC-V architecture.
- SiFive HiFive1: A development board based on the Freedom E310 RISC-V microcontroller.
Other popular options:
- ESP8266: A low-cost Wi-Fi module with an integrated microcontroller.
- ESP32: A more powerful Wi-Fi and Bluetooth module with an integrated microcontroller.
- Texas Instruments CC2640: A Bluetooth Low Energy (BLE) microcontroller for wearable and IoT applications.
Selecting the right microcontroller
Choosing the right microcontroller for an IoT device is crucial for its performance, power consumption and overall success. The following steps will help in selecting the right one.
First of all, define the requirements of the IoT device:
- Functionality: What specific tasks will the device need to perform?
- Connectivity: What communication protocols (Wi-Fi, Bluetooth, Zigbee, cellular, etc.) are required?
- Power source: Will the device be battery-powered, plugged in or have a combination?
- Processing power: How complex are the calculations or data processing tasks?
- Memory: How much memory (RAM and flash) is needed for storing data and code?
- Security: What security features are necessary to protect sensitive data?
Then, evaluate microcontroller features and decide the architecture of the microcontroller:
- CPU core: Compare the clock speed, instruction set and performance benchmarks of different microcontrollers.
- Peripherals: Check if the microcontroller has the necessary peripherals (e.g., timers, ADCs, DACs, UARTs) for the device's functions.
- Memory: Evaluate the amount of RAM and flash memory available.
- Connectivity: Ensure the microcontroller supports the required communication protocols.
- Power consumption: Compare the power consumption in different operating modes (active, sleep, deep sleep).
- Security features: Assess the built-in security features like hardware encryption, secure boot and trusted execution environments.
- Architecture: ARM Cortex-M Series is known for its balance of performance, power efficiency and flexibility. Similarly, other architectures have certain advantages.
After that, consider development tools and ecosystem:
- Development environment: Evaluate the availability of development tools, compilers and debuggers for the chosen microcontroller.
- Community support: Consider the size and activity of the community surrounding the microcontroller, as it can provide valuable resources and support.
- Third-party modules: Check if there are readily available third-party modules or libraries that can accelerate development.
Then, evaluate cost and availability:
- Microcontroller cost: Compare the prices of different microcontrollers that meet specific requirements.
- Development board cost: Consider the cost of development boards or modules if starting from scratch.
- Availability: Ensure that the microcontroller is readily available from reliable suppliers.
Finally, develop a prototype and test:
- Build a prototype: Create a prototype of the IoT device using the selected microcontroller.
- Test functionality: Verify that the microcontroller can handle the required tasks and meet performance expectations.
- Measure power consumption: Measure the device's power consumption to ensure it meets power budget specifications.
- Address issues: Identify and address any issues or limitations that arise during testing.
Follow these steps to choose the best microcontroller for an IoT device. Before development tools, price, power consumption or performance are considered, make a list of all unique requirements for each project.
Conclusion
Choosing wisely for an MCU might be challenging at times. The guidelines conveyed here should give designers a better grasp of what features to look for in IoT microcontrollers. The complete stack of software, hardware and networking must be considered while designing any aspect of a product.
