“With system-on-chip (SoC) playing an undisputed role in enabling connectivity and computing capabilities in the Internet of Things (IoT), the term has become an industry buzzword to the point that it is difficult to compare SoC with other types of integrated circuits (ICs). differentiate. Compared with single-function chips such as power management chips, SoCs integrate multiple Electronic functions on a single chip, while high-quality SoCs are composed of tightly coupled software and hardware functions running on tiny chips.

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By: Asem Elshimi, Product Marketing Manager, Silicon Labs

With system-on-chip (SoC) playing an undisputed role in enabling connectivity and computing capabilities in the Internet of Things (IoT), the term has become an industry buzzword to the point that it is difficult to compare SoC with other types of integrated circuits (ICs). differentiate. Compared with single-function chips such as power management chips, SoCs integrate multiple electronic functions on a single chip, while high-quality SoCs are composed of tightly coupled software and hardware functions running on tiny chips.

Other semiconductor products can be judged based on the number of transistors they integrate on a chip; however, this judgement method cannot accurately reflect the quality and complexity of the functions integrated on an SoC. In fact, building the same number of functions on an SoC using fewer transistors is actually a manifestation of ultra-high integration capabilities.

Little-known history of SoC development

The little-known development history of SoC may surprise some people in the industry. In fact, some SoC-related products have been released before the official launch of SoC products. The Computer History Museum claims that the first real SoC product appeared in a Microma watch in 1974. Also, a quick look at The Art of Electronics, published in 1989, reveals some schematics that look a lot like SoCs with stepper motor control, analog-to-digital converters, serial I/O, integrated ROM, timers, and event controllers . These early SoCs had another name that indicated their function rather than their architecture: Application Specific Standard Products (ASSPs).

Most of the SoC’s history has been out of the public eye. Developed by competitive technology companies, most of the early concepts for SoCs are hidden under the secrecy and protection of intellectual property laws. However, significant advances in techno-economics have not only made SoCs possible, they have also become necessary products.

In the late 1990s, the mobile phone revolution drove the development of integrating multiple functions on a single chip. Remember how bulky cell phones were in the past? Older cell phones contain at least a dozen chips that perform various functions: a central processing unit (CPU) that handles network configuration, user interface, and all advanced functions; RAM and Flash associated with the CPU; a baseband digital signal processor that performs the physical channel and math-intensive operations for speech coding; and a mixed-signal IC that manages the radio frequency (RF) transceiver. In order to continue to enhance the functionality of mobile phones and make them more attractive to consumers, manufacturers are constantly seeking further integration and miniaturization.

The rise of semiconductor intellectual property (IP) has opened up the possibility of such integration. IP cores and IP blocks are silicon-level designs (rather than physical chips) that can be integrated into the design of other chips and become the building blocks of larger systems. IP blocks can be storage, I/O, or processor cores. Semiconductor companies have started adding processor cores and memory cells to their chip designs. When semiconductor IP companies sell multi-module designs as “black boxes,” multi-module integration is already taking shape, ushering in the era of SoCs.

Today’s SoCs Can Do More Than Early Computers

SoCs can reduce the number of chips on a phone by at least 10 times. Integrating discrete components on a single chip significantly improves efficiency, reduces interconnect time, and enables SoC designers to perform system-level optimizations that result in significant power reductions. As a result, phones have gotten smaller, with significantly better performance and longer battery life.

Over the past two decades, traditional mobile phones have evolved into smartphones with further integration and carefully optimized implementations. Generation after generation of SoC design and optimization has provided a carrier for technological advancement, starting from the early mobile phone era, and has led us to today.

Continues to rise as IoT building blocks

Another important catalyst for the development of SoCs is the emergence of the Internet of Things. The possibility of connecting everything to the network with tiny, energy-efficient chips means we need to integrate more and more functions onto a single chip. Interest in building faster, interoperable IoT networks has also contributed to the rise of wireless SoCs that integrate RF transceivers, general-purpose microcontrollers (MCUs), numerous high-performance peripherals (amplifiers, ADCs, DACs), As well as non-volatile memory to perform application processing and network protocol stacks, while providing radio frequency connectivity for wireless networks.

A wireless SoC consists of multiple hardware functional units, including a microprocessor running software code, and a communication subsystem for connection, control, guidance, and interface between these functional blocks. SoCs contain many execution units that must frequently send data and instructions back and forth, which means that all but the most common SoCs require a communication subsystem. Originally, like other microcomputer technologies, SoCs used a data bus architecture, but many designs have now switched to simpler interworking networks.

An example of a modern wireless SoC is the Silicon Labs EFR32 Series 2 multiprotocol product.
As can be seen from the figure, the SoC integrates a large number of subsystems.

IoT end node products require miniaturization and power optimization. If the IoT is to connect electronics to everything, the electronics must be small and stay powered for as long as possible on small batteries. This may require sacrificing the processing power of the SoC to achieve.

Personal computers and smartphones can integrate common, interoperable operating systems on their relatively scalable memory storage, but SoCs need to sacrifice processing power and storage capacity for miniaturization and lower power consumption. Fortunately, due to the specificity of wireless IoT SoCs, their software can be optimized for various specific application scenarios. While this enables smaller, more efficient devices, it increases the complexity of the SoC software. SoCs located in larger systems may require interface software to function properly in larger systems. For stand-alone SoCs running at IoT end nodes, the requirements for the software stack become very complex. To be fair, a wireless SoC consists of two main, interdependent subsystems: software and silicon.

Another extremely important subsystem in a wireless SoC is security. While security is tied to hardware and software, it is worth considering itself as a separate subsystem because the security of an SoC is determined by its weakest link. IoT devices may encounter threats at various levels and therefore require security protection at all levels, including firmware, network, and user authentication.

Towards edge computing

It is estimated that by 2025, the net value of connected devices worldwide will grow to 51.9 billion (source: Omdia). One of the most anticipated developments in IoT is the incorporation of artificial intelligence and machine learning in edge devices. Edge intelligence refers to the collection and analysis of captured data on a nearby edge network to provide insightful insights. These processes enable IoT networks to make decisions locally without having to send data to the cloud and then receive decisions back. Since one of the most energy-intensive operations in a wireless SoC is radio frequency transmission, edge intelligence can go a long way in saving energy. In addition to energy savings, deploying machine learning on edge networks does not even require the transfer of massive amounts of data generated by IoT devices to the cloud, which is time-consuming, expensive, and raises data privacy concerns.

As artificial intelligence and machine learning are further integrated into edge devices, SoCs will continue to play a key role in the evolution of IoT. Thanks to better and more efficient semiconductor manufacturing and design techniques, we expect future generations of SoCs to have more computing power.