Meet microcontrollers – the tiny chips that can drive your innovations

Choose a microcontroller-agnostic design partner for faster, less expensive innovation projects.

Microcontrollers, also known as MCUs, are everywhere. These miniscule mini-computers can be found in almost every type of electronic product. Headsets, washing machines, hairdryers, smartphones… they all depend on MCUs. In fact, according to this article*, you have at least 20 MCUs in your home.MCUs were born in the early 1970s, revolutionising electronic product design and production and unleashing huge benefits including smaller size, lower cost, greater energy efficiency and a move away from combinatory logic – AKA simple functions designed in hardware. Their development has had an incredible impact on product design. As our lead hardware engineer Cori puts it: “MCUs mean we could do more with much smaller.”But did you know MCUs come in many shapes and sizes and with differing attributes? Did you know their cost and availability can make or break an innovation project? And do you know how to choose and source the right MCU for your product?

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Cori explains more…

Cori, what are microcontrollers?

Microcontrollers — AKA Microcontroller Units or MCUs — are miniature computers contained on a single electronic chip, typically soldered onto printed circuit boards. Most MCUs are designed to perform just one basic function – known as an embedded application – repeatedly. For example, an MCU in a smart light bulb could connect to WiFi and wait for instructions from a control app.

MCUs contain memory, oscillators, inputs / outputs and differing numbers of pins, which look like little legs, to connect and send and receive information from the outside world. MCUs are fundamental to most electronic products as they control elements of the system and run firmware (software programs on a hardware device).

But it’s also important to note that not every electronic product contains an MCU. For example, advanced USB phone chargers have a controller chip that delivers as much current as possible to the phone for faster charging.

How do MCUs differ from microprocessors?

Most microprocessors don’t have any RAM or ROM memory, and can only be used as part of a wider system, whereas MCUs have components including memory and oscillators. MCUs are typically used for simple, specific, repeat tasks, while microprocessors are more versatile and tend to be faster than MCUs. MCUs are easier and cost pennies to manufacture, and take less power than processors to run. Microprocessors are typically found in PCs and laptops.

A recent development is the growth of SoCs (system on chip) which describes MCUs with additional functions integrated – for example Bluetooth or a graphics processing unit (GPU).

What size are MCUs?

Physically, they’re always shrinking. A small 8-bit MCU be as small as 2mm by 2mm. We use 32-bit MCUs (4mm by 4mm) in products like our etee VR controllers. In terms of memory, the most common MCUs are 8-bit or 32-bit. The more memory, the bigger and more complex the program can be, and usually the speed of execution is higher too. We can always advise on the right MCU for specific applications.

What different types of MCU are there?

If you want to create a new product, you need an experienced partner to advise and source the right MCUs. At TG0 we’ve worked hard to build our expertise and our trusted MCU suppliers, which are typically based in China. This means we can advise on MCUs that fit not only your technical considerations, but your business ones too.

Technical parameters to consider include:

• Size, in terms of available inputs and outputs
• Size, in terms of available memory
• Package size, in terms of number of pins. Some MCUs are 1cm square with up to 128 pins. Others are very small: 2 x 2mm with 32 tiny pins, enabling more components to be fitted on the same circuit board
• How fast the MCU can compute
• Communication protocols available – does the MCU need to communicate through a USB for example?
• Certification and temperature rating; temperature is important because it impacts on safety
• Firmware stack and environment
• Special features such as capacitive sensing or a real-time clock
• Architecture – for example is it suitable for embedded applications or does it need to be a SoC?
• Allowable power supply and voltage ratings
• Power consumption – important depending on if it’s a battery or mains operated device
• Wireless capability, such as WiFi or Bluetooth

Business considerations include:

• Availability and supply chain
• Cost per unit
• Sustainability

How much do MCUs cost?

We tend to buy-in MCUs and solder them ourselves in the prototyping stage if the MCU is physically big enough, but at production stage MCUs would typically be integrated on a factory line. In prototyping MCUs can cost anywhere between 20p to a couple of pounds per unit, but the cost depends on the specification, order quantity and supplier.

When do you have to start considering which type of MCU you want to use?

Right at the beginning of design, as availability and technical attributes can make or break the ability to bring a product to market. The choice of MCU heavily influences the Bill of Materials cost (the amount of components in the products), and the firmware capabilities. Other key MCU considerations include will it enable ramping up into mass production, will the MCU remain available, does it fit the price points, can it fit into a lean, effective manufacturing process, can it be programmed in a factory setting?

New types of MCUs can create new opportunities. For example, new ultra low-power MCUs can be integrated into wearable products.

Do different industries have different MCU requirements?

Absolutely. In automotive and aerospace for example, we have to use MCUs that fit particular grades. These ‘automotive-rated’ MCUs have higher temperature ranges, making them more expensive, but safer in specific environments. Wearable and IoT products typically require low-power MCUs with wireless capabilities. TG0 works in automotive, so we’re knowledgeable about automotive-rated MCUs, and can combine them with our sensor technology to meet safety and compliance needs.

How does TG0 work with MCUs?

A key attribute of our patented touch sensing technology is that we are MCU-agnostic, which gives both our clients and our design team enormous flexibility in the design and prototyping process, and cuts time to prototype down to weeks instead of months. We know how to tailor Bill of Materials to client cost and performance requirements, and we support a range of communications protocols including USB, SPI and CAN, again delivering more flexibility to our clients.

But probably the most exciting area we’re working in is combining new technologies with MCUs. Right now, we’re doing some cool stuff with machine learning and signal processing, and how that can impact on user experience.

If you’d like to learn more about TG0’s fast, lean, iterative product design and prototyping process, email Kuba@tg0.co.uk

*https://www.circuitstoday.com/microcontroller-invention-history