Top Microcontrollers for Embedded Systems

Introduction to Microcontrollers

Microcontrollers, or MCUs for short, can be found in most electronic embedded systems these days. From washing machines, to digital audio processors, to flight control systems, and much more. MCUs are very flexible processors that can be typically programmed in C/C++, are packaged together with non-volatile (FLASH) and volatile memory (RAM), and an array of peripherals and I/O. Sometimes these MCUs may also be wireless-capable (for example, Bluetooth or WiFi).

When starting out in electronics and needing to add a microcontroller to a custom hardware design, the massive amount of choice can initially seem overwhelming. There are many different vendors (such as Texas Instruments, ST, Microchip, and so forth) and per vendor there is an even greater selection of microcontrollers - not to mention even the variation within a specific microcontroller family.  For instance, a quick, generic search using Octopart for the powerful STM32H7 line of microcontrollers yields nearly 250 different results!

The specific microcontroller of course has to be chosen depending on the system that is being designed. Here, many aspects need to be taken into account, such as available memory, required peripherals (such as UART, SPI, etc.), cost, package type, availability, software environment, documentation quality, and more.

In this article, we will explore some very common microcontrollers used in the industry today. Hopefully, this will narrow down the selection – at least in part – for your next project, and expose you to popular MCUs that can be found in many modern embedded systems.

STMicroelectronics STM32 MCUs

By far one of the most popular and well-known manufacturers of microcontrollers, as of writing this article, is STMicroelectronics (ST). This is for good reason, as their MCUs are well-priced, available in many different configurations and performance grades, and can be debugged and programmed using, for example, ST’s free STM32CubeIDE development environment. Their STM32 line of MCUs are based on ARM Cortex processor cores.

In addition, ST provides many pre-written drivers, as well as a hardware abstraction layer (HAL) for their parts. These are integrated in STM32CubeIDE. Although there may be occasional flaws in the HAL, these drivers substantially decrease time-to-market and provide an excellent starting point for firmware development.

When it comes to part selection, ST offers numerous, different microcontroller families. From simple STM32F0 MCUs that may be useful for simple ‘glue logic’, to very powerful STM32H7 MCUs that can run real-time digital signal processing algorithms, and anything in between. Furthermore, ST also offers wireless-capable MCUs, such as the STM32WL and STM32WB lines, for WiFi and Bluetooth connectivity respectively.

Figure 1 STMicroelectronics MCU Families (Source: STMicroelectronics)

My personal favourite MCUs by ST are the F4 and H7 series, which I have used extensively in digital signal processing applications for audio. Make sure to check out this full STM32-based hardware design tutorial using Altium Designer, to see how easy it is to add a microcontroller to your own projects!

Nordic Semiconductor nRF Series

If you are in the market for wireless-capable microcontrollers, such as ones allowing for Bluetooth or WiFi capability, make sure to take a look at Nordic Semiconductor’s line of nRF series of microcontrollers. These are very capable devices, especially if you have low power requirements.

Personally, I am a fan of their nRF54 line of Bluetooth LE (low energy) devices and have used them in various ultra-low-power products. Keep in mind though that typically the packaging of these parts can get very small and may increase your PCB fabrication and assembly costs, although they offer ‘more accessible’ QFN package types as well. Of course, these tiny package sizes can be very beneficial for, for example, miniature and wearable products.

Figure 2 nRF54 Bluetooth LE Microcontroller (Source: Nordic Semiconductor)

Espressif ESP32 Microcontrollers

As an alternative to nRF, Espressif offers their ESP32 line of microcontrollers (or RFSoCs, rather) that are incredibly affordable and pack quite a punch. Often offering dual-core microcontrollers, WiFi and Bluetooth capability, and a reasonable peripheral count. Additionally, ESP32’s online community and user base is very large, so you will be sure to find help with your project should you need it.

If you would like to learn how to incorporate ESP32 microcontrollers into your own hardware designs using Altium Designer, make sure to check out this tutorial video!

Figure 3 ESP32-C3 Microcontroller (Source: Mouser)

Both manufacturers and third-party manufacturers also offer pre-certified system-on-modules that integrate antennas (or connectors for off-board antennas), which can substantially simplify the certification process, in case you want to sell your design commercially.

Figure 4 ESP32 Pre-Certified Module (Source: Mouser)

Raspberry Pi RP2040 Microcontrollers

A comparatively new microcontroller is the RP2040 by Raspberry Pi, most famously known for their Raspberry Pi single-board computers. This microcontroller features a dual-core ARM Cortex-M0+ processor, numerous peripherals, as well as something very interesting known as a Programmable I/O section. Big selling points are the RP2040’s low price (less than 1 USD in low quantities), flexibility, and availability.

Figure 5 Raspberry Pi RP2040 (Source: Raspberry Pi)

Microchip, NXP, and Texas Instruments Microcontrollers

Similar to the STM32 line of microcontrollers, other manufacturers, such as Microchip, NXP, and Texas Instruments offer their own series of MCUs in a variety of flavours. The capabilities of these parts across these manufacturers are typically quite similar, so being familiar with a company, liking their documentation, or simply availability of the parts may be selling points.

From 8-bit to 32-bit, to DSP-capable, and also wireless-capable MCUs, Microchip is well-known for their PIC microcontrollers. NXP offers general purpose, i.MX real-time, and automotive-targeted microcontrollers. Lastly, Texas Instruments also have a sizable portfolio of microcontrollers - however, from personal experience, I have not seen these too frequently in commercial designs, compared to the other manufacturers.

Some of the flagship components from these manufacturers include:

• Microchip: Their products include PIC microcontrollers and the hugely popular ATMega product line acquired from Atmel
• Texas Instruments: The MSP430 series is their most popular microcontroller line, there is also the SimpleLink line which integrates WiFi
• NXP Semiconductor: i.MX is arguably their most popular product line, there is also the LPC product line which appears in many industrial-grade systems

Compare Microcontrollers with Octopart

We’ve explored some top microcontroller manufacturers and their devices, but keep in mind that this is in no way an extensive list and is quite general. There are many other manufacturers that offer great microcontrollers that were not mentioned here – as well as some of the older MCUs, such as ATmega variants, which are still in use by many designers across the world today.

Make sure to check out Octopart to help you out with choosing the right microcontroller for your next design. When you have chosen an MCU, be sure to use a powerful ECAD tool, such as Altium Designer, to bring your design to the next level.

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