What is an SoC? Differences Between SoCs and MCUs

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What is an SoC?
Differences Between SoCs and MCUs

I am Peter, an embedded engineer at RJY Display. With over a decade of experience in microcontroller (MCU) development, I’ve come across numerous articles about System on Chips (SoCs). Initially, many of these articles felt overly academic and hard to grasp without direct experience with SoCs.

To simplify, think of an SoC as a customized version of an MCU. However, SoCs are not limited to MCUs; they can also be custom versions of more advanced CPUs and MPUs. It’s a common misconception that all SoCs are high-performance; in reality, there is a significant market for low-end SoCs as well, depending on product requirements.

What is an MCU?

An MCU, or Microcontroller Unit, is a single-chip computer, commonly referred to as a microcontroller. An MCU requires external circuitry to perform its functions. Think of the MCU as the brain, while the other components like buttons, buzzers, LEDs, and displays act as sensory and output organs.

We program the MCU using languages like C or assembly. Once the program is compiled and downloaded into the MCU, it can control the peripherals to perform various tasks.

Key Features of MCUs:

  • Integrated Components: A basic 51-core MCU consists of a CPU, RAM, ROM, timers, serial ports, and external interrupts. Advanced MCUs, like those based on the ARM Cortex-M3 architecture, integrate additional peripherals and resources.
  • Cost: MCUs are generally inexpensive, ranging from a few cents to tens of dollars.
  • Common Manufacturers: Popular MCU manufacturers include STC, STMicroelectronics, Renesas, and Atmel.
  • Popular MCUs: Examples include STC’s 51 series, STMicroelectronics’ STM8 and STM32, Arduino’s AVR, and TI’s MSP430.
  • Operating Systems: MCUs typically run Real-Time Operating Systems (RTOS) or are programmed bare-metal, meaning they do not use an operating system like Linux.

The figure below is a block diagram of a standard STM32F MCU module:

What is an SoC?

An SoC integrates an MCU or CPU with specific functional modules tailored to a particular application. Low-end SoCs might combine an MCU with additional peripherals, while high-end SoCs integrate more powerful CPUs or MPUs with specialized modules.

For example, consider SoCs used in metering applications:

Key Characteristics of SoCs:

  • Customization: SoCs are designed with specific applications in mind. For instance, a metering SoC might include modules for energy measurement.
  • Integration: SoCs often integrate wireless communication modules, like Bluetooth or Zigbee. For example, the TI CC2541 Bluetooth SoC features a 51-core MCU with built-in wireless radio and runs TI’s Bluetooth protocol stack to achieve Bluetooth functionality.
  • Cost and Efficiency: By integrating specific functionalities into a single chip, SoCs can reduce development time, enhance stability, and lower costs.
CC2541

Look, I’ve highlighted in red – the Bluetooth that you always thought was so high-end, turns out to be based on a 51-core!

Observe its peripheral resources as well. Besides some common peripherals like GPIO, serial ports, timers, and so on.

It also has an integrated wireless radio module (Radio Arbiter) on the chip, along with TI’s Bluetooth protocol stack, which enables the Bluetooth functionality.

So, one common characteristic of SoC chips is that they are designed to provide a more convenient, lower-cost, and more stable solution to meet the specific needs of a particular industry.

Differences Between MCUs and SoCs

To summarize, an MCU is a general-purpose microcontroller, while an SoC is a specialized chip that integrates an MCU or CPU with additional modules tailored for specific applications. Using an SoC can greatly simplify the development process for complex applications, such as wireless communication or energy metering.

For instance, if you’re developing a product that needs to decode specific wireless protocols, using an SoC with built-in decoding capabilities can save significant time and effort compared to implementing the functionality with a standard MCU.

In product development, it’s often beneficial to explore existing SoCs that meet your application’s requirements before opting to design custom solutions. This approach can streamline development and improve product performance.

RJOYTEK is a technology company that specializes in LCD modules and board development. We have a complete LCD module cutting, cleaning, chipping, and assembly production line. We also have an independent design team. Our factory has passed ISO9001, ISO14001, and ISO45001 certifications. We are capable of accepting large-scale ODM&OEM orders. If you need further technical support, please feel free to Contact Us!

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