System-on-a-chip or SoC combines several hardware components and the controlling software on a single chip. This almost always includes one or more CPUs, memory units, communication buses, power management controllers, I/O controllers, and even the GPU or APU.Hence, it eliminates the need for separate hardware modules as required by the desktop CPU to control and communicate. But there is still a lot more to an SoC that makes it the demand of the digital world.In this guide, we are going to discuss the SoC and how it varies from our regular desktop CPU.
What is System on a Chip?
The digital world has seen a significant reduction in the size of the electronic components that we use now. From the use of massive-sized computers to the ones that can be held in our hands, integrated and scaled-down technologies have become a boon for us.However, miniaturization has been possible mostly through the rapid progress in processors used in them. The present CPUs, known as microprocessors, consist of the main processing power, or the brain, through the use of a single IC in a small space. And these are continued to upgrade even more.The next revolution came with the production of a microcontroller that integrated the microprocessor, RAM, and Input/Output interfaces on a single chip. These microcontrollers could run specific applications and programs without needing more hardware modules for memory and other peripherals.Now, we have upped the game even further than the microcontroller with the release of the System on a chip. It is similar to the microcontroller but with features beyond what a microcontroller possesses.It incorporates almost everything a microcontroller has, such as the CPU, memory, I/O controllers, and adds up advanced buses, Graphics Unit, Wireless controllers, GPS, and many more. It even consists of an Operating system that can drive a multitude of applications like a normal computer in comparison to a specific program operated by a microcontroller.One of the devices that consists of the SoC is the mobile phone. All the tasks, such as taking photographs, calling, using the internet, operating games, etc., that you do on the phone are controlled by a single SoC chip. Apart from the phone’s chip, SoCs, the size of a shirt’s button, are also found in wearable devices and can do almost everything that a phone can.Advancements in SoC, such as Apple’s M1 chip, have now facilitated its use in computers at full functionality.
How Does it Differ From a Desktop CPU?
Both the SoC and a CPU have the same task of carrying out the processing operation in a computing system. However, the SoC varies from the traditional CPU in terms of its incorporation of all required components in a single silicon base. While we use CPUs for our regular work, SoCs are platform or area-specific.Furthermore, the SoC does not always need to have a CPU and can use a microcontroller or any application-specific unit in place of it. However, the desktop CPU is an integral part of the traditional PC, and almost everything revolves around it.Apart from this, there are a few differences between these two chips based on the following features.
Size
As all the components lie on a single chip, its size reduces significantly. Yes, the CPU is also relatively small, but because of it’s high computing power the size is much bigger.You can find the SoC even the size of a shirt button, as seen in the wearables. Thus, the SoC can be valuable for thinner and small-sized computing devices and when you need to cover extra space with other complimentary parts.
Processing Capacity and Latency
Most SoCs are domain-specific, unlike the general computing of the desktop CPU. This makes the processing capacity and efficiency of the SoC much better for that particular application.Furthermore, the SoCs have integrated buses and cache memory that communicates with all the components. This makes the data flow and retrieval much faster in the SoC, lowering the latency in comparison to the external buses incorporated in the PC with a desktop CPU.
Power Usage
The SoCs require much lesser power to carry out their processing and domain-specific functionality. It is mostly due to integrated circuitry and shorter wiring and connections.Thus, one of the reasons mobile phones with SoC last longer than a laptop with a normal CPU is their lower power consumption. And this has also led to a higher value for processing per power required, leading to an efficient chip.But, having said that, the SoCs still cannot outperform some of the latest powerful CPUs due to the limitation in their power usage capacity.
Flexibility
Since the SoC has integrated components, you cannot remove or replace the individual part and use another one. And it is also quite difficult to replace the whole SoC with a new one. For instance, when a smartphone’s chip gets damaged, you will have to get a new phone in most cases.However, you have the option to change the desktop CPU if it stops working. Or, you can even get a more powerful processor for your PC when you want to upgrade your system.Talking about upgrades, you can also integrate the CPU with other high-end components, such as GPUs, manually, improving the overall efficiency of the system. But, in the case of an SoC, the integration is made automatically, and you cannot hand-pick what components you would like to use for the upgrade.Nevertheless, the ability to use an SoC without the need for any additional hardware and in a relatively smaller area is still flexible for utilization in varying types of computing devices. Regarding the desktop CPU, it is pretty useless without other components.
Cost
Being an all-in-one technology, the cost of the System-on-a-Chip is much higher than a desktop CPU. But, if we look into the cost of the design per domain and cost per processing power, it is a lot cheaper. Furthermore, the SoC can also be manufactured in bulk for a specific domain, lowering its price for that particular application.Still, if you want to use an SoC for general-purpose computing, it is pricey, making the traditional desktop CPU the right choice for its lower cost.While we talked about the differences, and preferably the superiority of SoCs, there can definitely be curiosities about how they are designed and their types. Let’s look at them below.
Types of System on a Chip
The System on a Chip is usually categorized into three types based on the nature of the components it consists of.
Microprocessor-Based SoC
These System-on-a-chips are designed around a microprocessor. First, the CPU is included, and other parts, such as memory, GPUs, WiFi, etc., are incorporated into the chip.One example of Microprocessor-Based SoC is the Snapdragon chip used in mobile phones. It consists of a Kryo CPU and is expanded with 3G/LTE, WiFi, a Camera Module, a USB controller, GPU, and so on. Furthermore, Apple’s M1 chip is also one of them.
Microcontroller-Based SoC
These SoCs are built by using a microcontroller as the main processing unit. All other required features are added to work with the MCU.CC2540 SoC, built by Texas Instruments, is designed by using an 8051 microcontroller, and components such as Bluetooth module, Battery and temperature monitor, USB interface, etc. are added to it.
Application-Specific SoC
Application-specific System-on-a-chip specializes in a particular domain instead of general computing tasks. Here, the processing unit carries out only a specific task, and the chip incorporates only the required additional components needed in a particular area.For instance, the chips used to drive the wearables consists of the specific components and software to run fitness monitors, time, and cell network in some. Similarly, an SoC for video processing may include a controller dedicated to image compression, color reproduction, and so on.Apart from this, defense electronics, communication in automobiles, IoTs, etc., are some specific applications of SoC.
How is its Architecture Designed?
As the System-on-a-Chip is particularly for area-specific computing, its architecture and components vary from one to another. Nevertheless, the basic platform and configuration remain the same, focusing on four major functionality: Control, Communication, Processing, and Memory.Since all the components in an SoC act as a single unit, there needs to be the main hardware that controls the logical operation and signal flows in all of them. This role is given to the microprocessor or microcontroller. It ensures that a number of computations are continuing in parallel and that the process is smooth without any conflicts.However, the microprocessor’s cache is centralized to work with it only and not for other components. So, its architecture is designed with several system buses, serial connections, point-to-point connections, etc., for dedicated communication. These communication means are responsible for the transfer of synchronization signals, data or address transfer, and control signals.For that purpose, there are high-speed buses controlled by the bus master, which are joined by bus bridges to allow signal transfer across every component.The next architectural design parameter is the requirement of processing functionality. The central processing is done by the microprocessor or microcontroller. And other computational units are domain-specific. For instance, an SoC for health monitoring consists of specialized units to process the signals received from the human body.After the integration of all these units, the SoC requires distributed memory system for cache storage, temporary data, as well as permanent files. For this, there are several major types of memory: Registers or DRAM for fast memory retrieval, Non-volatile ROMs for permanent storage of read-only data of programs, and NVRAM for data storage.Finally, if it needs any further hardware as per custom requirements, then these are integrated to be controlled by the main processor and communicated through the buses. And it can make use of the processing unit and memory particularly suitable for it.
