Author:
Greg Robinson, Vice President of MCU Business Unit at Microchip Technology Inc.
Internet Connectivity Drives Processing Demands
Embedded systems are continuing their technological evolution at an accelerating pace; the functionalities of devices in our homes, vehicles, and workplaces are advancing rapidly. A key driver of this progress is the ability of even the smallest electronic devices to connect to our modern network infrastructure. Wi-Fi®, Bluetooth®, and other connectivity options make field updates and maintenance easier while enhancing the advantages of artificial intelligence and machine learning algorithms. This increased connectivity effectively turns these devices into IoT edge nodes—but it comes at the cost of increased processing demands and larger memory subsystems.
System Challenges
Most embedded systems are also “connected” to their immediate environment—meaning they provide some type of environmental sensing, mechanical actuation, or human-machine interface functionality. For example, a smart thermostat is equipped with a range of buttons or capacitive sensors for human input and is connected to a local network of temperature and humidity sensors. Most embedded systems are “connected” to their environment—meaning they possess some form of environmental awareness, mechanical control, or human-machine interaction capabilities. For instance, a smart thermostat not only has buttons or touch sensors for human interaction but is also connected to a local network of temperature and humidity sensors. Similarly, the primary goal of connected cooking devices is to understand your expectations for food temperature and translate that into precise heat control. These systems, primarily based on “analog” signals, are gradually entering the fast-paced world of cloud communication, which presents a dilemma: do you design systems for the slow inputs of the analog world, or do you sacrifice the precision of analog signals for increased speed and overall functionality?
To better understand this issue, we can look at a common and simple example—IoT edge sensor nodes.
Analog Subsystems
IoT edge sensor nodes require some analog subsystems to measure and monitor environmental conditions such as temperature, humidity, and motion. Analog subsystems typically include a microcontroller (MCU) to read sensor data, perform some form of processing, and communicate over a network. Generally, environmental data changes relatively slowly, so most edge nodes do not need to process continuous, uninterrupted data streams. Since edge nodes typically rely on small batteries to operate for years, they spend most of their time in a low-power “sleep” mode, waking periodically to detect environmental changes. During wake periods, the node collects data and transmits it over the network. Afterward, it returns to sleep mode until the next measurement is needed. In our highly interconnected world, as the number of edge nodes and the data they collect increase, power efficiency and low-power operation become critical design considerations for extending the battery life of analog subsystems.
Segmented Design of Embedded Systems
To achieve efficient embedded systems, it is often necessary to segment the system into different “speed domains” and connect the fast main processor to the analog subsystems via bridges. This partitioned design allows the analog subsystems to focus on slower-changing tasks while the fast main processor handles complex tasks that require high-speed computation. This way, each processor can leverage its strengths. As more devices require connectivity, I3C® has emerged as the next-generation serial communication interface specifically designed to support high-speed communication between chips. As an upgrade to I2C, I3C not only offers faster speeds but also features smarter interfaces and more powerful control capabilities. Importantly, I3C remains compatible with existing I2C devices, allowing for easy integration into current hardware platforms. Additionally, I2C devices can coexist with I3C controllers operating at 12.5 MHz, meaning existing I2C bus designs can gradually transition to the I3C standard. For example, a microcontroller that supports both I3C and traditional communication interfaces (such as I2C, SPI, or UART) can serve as a bridging device. This bridge connects the fast processor to the sensors via the microcontroller, which is responsible for reading sensor data, performing calculations, and efficiently transmitting the results. This design not only maintains the high-speed performance of the I3C bus but also enables communication between the I3C controller and I2C/SPI devices through the microcontroller. By implementing a well-segmented design for embedded systems and utilizing the I3C interface, more efficient and stable system designs can be achieved.
PIC18-Q20 MCU
Microchip has launched the PIC18-Q20 product family, specifically designed for modern distributed processor embedded systems. These microcontrollers (MCUs) offer advanced serial communication interfaces, including up to two I3C peripherals, enabling high-speed connections to multiple buses, greatly enhancing system flexibility. Additionally, they incorporate traditional communication protocols such as UART, SPI, I2C, and SMBus, allowing them to seamlessly integrate into systems as bridging devices while isolating I2C/SPI devices from the pure I3C bus. This design not only maintains the high-speed performance of the I3C bus but also facilitates communication between the I3C controller and I2C/SPI devices through the microcontroller. The PIC18-Q20 also supports multiple voltage domains, meaning it can easily connect components operating at different working voltages, eliminating the need for level shifters, reducing material costs, and simplifying system design. Furthermore, the PIC18-Q20 microcontroller integrates core-independent peripherals (CIPs) that can operate independently without continuous CPU intervention and communicate directly with other peripherals. These hardware-based functional modules consume very little power, require minimal coding, and occupy less RAM and flash resources while achieving the same functionality as software. Moreover, a single MCU can enable multiple functional modules simultaneously. Designers can easily customize combinations of CIPs, including I3C peripherals, using the MPLAB® Code Configurator (MCC)—a simple graphical user interface (GUI) tool—to generate application code without delving deeply into the datasheet. By utilizing CIPs, engineers can manage each system task in a partitioned manner, simplifying functionality implementation and reducing component count, code size, development time, and power consumption.
Conclusion
In our rapidly changing world, technological advancements demand devices to have faster processing speeds, more efficient connectivity, and smaller sizes. While modern electronic devices are increasingly connected to the external world, there remains a need for miniaturized and energy-efficient analog subsystems to sense and measure data from the “real world.” Since environmental data changes are typically slow, a balance must be struck between speed and precision in design.
To achieve efficient embedded systems, it is often necessary to segment the system into different “speed domains” and connect the fast processor to the analog subsystems via bridges. As I3C gradually becomes the mainstream interface for high-speed communication between chips, engineers need to select advanced microcontrollers (MCUs) that can comprehensively support high-performance digital processing needs while ensuring these MCUs maintain high-precision processing capabilities for analog signals in next-generation designs.
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