In this chapter, we will understand the typical Architecture of Embedded Systems. Understanding the embedded system architecture is very important for personnel engaged in the design and development of efficient embedded systems. Hence, developers and engineers will find this chapter very useful, as it will provide an overview of embedded system components, design considerations, and emerging trends in embedded system architecture. So, let’s begin our journey with knowing the basic meaning of embedded system architecture.
What is Embedded Systems Architecture?
Embedded Systems Architecture can be defined as the structure or framework that provides information about how different components, both hardware and software, of an embedded system are connected together and interact with each other.
Embedded systems architecture is generally designed and optimized to perform specific tasks and provide real-time computing capabilities with ensured efficiency, reliability, and performance.
Components of Embedded Systems Architecture
The architecture of an embedded system can be understood by separating it into the following two sections –
- Hardware
- Software
Both these sections together define the functional capabilities and performance of an embedded system. Let’s discuss each of these sections and their components in detail.
Hardware Components of Embedded Systems Architecture
The hardware section forms the physical skeleton of an embedded system. It is made up of electronic components like transistors, diodes, resistors, ICs, etc. It provides a physical interface to interact with the external environment and execute software.
The main hardware components of the embedded system architecture are explained here –
Microprocessor or Microcontroller
Microprocessors or microcontrollers are data-processing devices and are used as the key processing elements in embedded systems. In an embedded system, a microprocessor or microcontroller executes the instructions to process the input data and produce the results. However, there is a difference between a microprocessor and a microcontroller, which is that a microprocessor provides only data processing capabilities, but a microcontroller combines processor, memory, and IO peripherals into a single chip.
Memory
In embedded systems, memory is provided to store components like ROTS, firmware, application software, and data. Embedded system memory is classified into two main types as follows –
- ROM (Read Only Memory) – It is provided in an embedded system to store firmware and RTOS.
- RAM (Random Access Memory) – It is used to hold temporary data and instructions required for the processing of inputs.
IO Devices
An embedded system can have different types of input and output devices. Some very commonly used input devices in embedded systems include a keyboard, touchpad, touch screen, or some push buttons/switches. While, the most widely used output devices in embedded systems include seven-segment displays, character displays, or LCDs.
However, some embedded systems do not have any output devices, but they are provided with ports to connect external devices depending on the needs.
Peripheral Interfaces
These are nothing but ports provided in embedded systems to connect external input and output devices. Some common examples of peripheral interfaces in embedded systems include analog and digital inputs, communication ports, and sensors or actuators. The availability of these interfaces in an embedded system depends on the application requirements for which the system is designed.
Networking Interfaces
These components are provided in embedded systems to network them with the external world. The most commonly used network interfaces in embedded systems are Ethernet, Wi-Fi, GSM, 4G, 5G, etc.
In embedded systems which are specially design to use in IoT devices, network interfaces like LoRaWAN or Zigbee are provided.
Power Supply
This hardware component is responsible for providing a stable and reliable power supply to the entire embedded system so that it can function correctly. In embedded systems, power supply can be provided from different sources like a battery or AC mains. It is important to ensure that the power supply used in embedded systems has a stable and required level of voltage and current so that the system can operate as expected under all conditions.
Software Components of Embedded Systems Architecture
The software components in embedded systems architecture define functionalities and provide control over the hardware components. A typical embedded system comprises the following components in its software section –
Firmware
Firmware is a piece of software written in a low-level language and permanently stored in ROM. Embedded systems firmware are responsible for managing the basic operations like initialization, input-output, interfacing, etc.
Real-Time Operating System (RTOS)
Embedded systems are powered by RTOS to make hardware functional and manage tasks or operations. RTOS are optimized to perform operations within a certain time constraint. Some popular examples of embedded systems RTOS include FreeRTOS, VxWorks, etc.
Device Drivers
These are software that help the operating system to identify and manage different devices and hardware peripherals connected with the embedded systems.
Application Software
In embedded systems, several different types of application software are used to perform different tasks. These software are specific to the application for which they are designed.
Within the architecture of the embedded systems, the above-listed hardware and software components are tightly linked together to perform the dedicated tasks.
Design Considerations for Embedded Systems Architecture
While designing embedded system architecture, the following important considerations must be kept in mind –
Real-Time Constraints
In general, embedded systems are designed to operate in a real-time environment. Hence, timely execution of instructions becomes critical for those embedded systems. While designing the architecture of an embedded system, the developer or engineer must ensure that the architecture will support the real-time operating systems or other task scheduling mechanisms, so the system can perform tasks within specified time constraints. Also, the processor or peripheral interfaces must support real-time functionality.
Reliability
Reliability is one of the most important characteristics of embedded systems. Because embedded systems are designed to perform specific tasks, hence they must offer high reliability so their behavior can be predictable.
Fault Tolerance
The architecture of embedded systems must be designed to have fault tolerance features like error detection and correction, redundancy, latency, etc. These fault tolerance characteristics are important to ensure that the system will be functionally stable even in the presence of faults.
Power Efficiency
Since embedded systems are used as a part of a large system, hence their integration impacts the power performance of the entire system. It becomes more critical in the case of battery-powered devices. Hence, while designing the architecture of embedded systems, it must be taken care that the system will require minimal power to operate. This can be achieved by incorporating power management techniques like providing power-saving modes, using low-power components, etc.
Scalability and Flexibility
Embedded systems architecture must be easily scalable and flexible in terms of reconfigurability for different applications. Hence, it is advisable that the architecture of an embedded system should have a modular design so it can be easily upgraded and free to expand depending on the needs of the application.
Emerging Trends in Embedded Systems Architecture
The following are some major future trends becoming popular in the field of embedded systems architecture –
- IoT Integration – The increasing deployment of IoT devices driving the need for more complex embedded system architectures that can provide seamless connectivity, interoperability, and enhanced security features.
- Edge Computing – Embedded systems architectures are also enabling integration of edge computing and allowing them to process data near to their source.
- AI and ML – Modern embedded systems architectures are being designed to support artificial intelligence and machine learning to provide cognitive decision-making.
Types of Embedded Systems Architectures
Some of the commonly used embedded systems architectures are explained below –
Single Microcontroller
In this architecture of the embedded system, a microprocessor, memory chip, and IO peripherals are combined into a single chip. This embedded system architecture is known for its cost-effectiveness. It is generally used in simple applications like home or office appliances.
Microcontroller with External Memory
In this embedded system architecture, a microcontroller is integrated with an external memory unit. Hence, this architecture is often employed in applications that require more memory and processing capabilities.
Microprocessor-Based Architecture
This embedded system architecture comprises a microprocessor with an external memory unit and IO devices. This architecture is widely used in devices like smartphones, tablets, and laptops.
Complex System-on-Chip (SoC)
The SoC embedded system architecture is mainly used in high-performance applications like advanced automation systems, automobiles, and gaming consoles. In this architecture, multiple processors, memory chips, and IO peripherals are combined into a single chip.
Conclusion
So, this is all about embedded systems architecture. From the above discussion, we can conclude that embedded systems architecture is an important concept for designing efficient and reliable embedded systems and devices. The architecture of embedded systems allows engineers and developers to optimize the system designs to meet the specific needs of various applications. Let’s move to the next chapter in the tutorial and learn about the applications of embedded systems.