Embedded System : Complete Guide

An embedded system comprises computer hardware and software tailored for a specific task, potentially operating within a larger framework. These systems can be either programmable or possess fixed functionality. They find application across various domains including industrial machinery, consumer electronics, automotive, medical devices, surveillance cameras, digital timepieces, household appliances, aircraft, vending machines, toys, and portable gadgets.

Despite being computing entities, embedded systems exhibit a wide spectrum of user interaction, ranging from no user interface (UI) on single-function devices to intricate graphical user interfaces (GUIs) seen in mobile devices. User interfaces may encompass physical controls like buttons, light indicators (LEDs), and touchscreen interfaces. Additionally, some systems integrate remote user interfaces.

 

According to forecasts by MarketsandMarkets, a business-to-business (B2B) research entity, the embedded systems market is anticipated to reach a valuation of $116.2 billion by 2025. Prominent chip manufacturers serving the embedded systems market encompass esteemed technology giants such as Apple, IBM, Intel, and Texas Instruments. This projected growth is fueled in part by ongoing investments in artificial intelligence (AI), mobile computing, and the demand for chips optimized for advanced processing capabilities.

 

Instances of embedded systems

 

Embedded systems find widespread application across diverse technological landscapes spanning various industries. Here are some illustrations:

 

1. Automobiles: In modern vehicles, an extensive array of embedded systems, often numbering in the dozens or even hundreds, are integrated to fulfill distinct functionalities within the automobile. These systems encompass fundamental utilities alongside entertainment and user-centric functions. Examples of embedded systems in consumer automobiles include cruise control mechanisms, parking sensors, suspension control units, navigation systems, and airbag deployment systems.

 

2. Mobile phones: These devices house numerous embedded systems, encompassing graphical user interface (GUI) software and hardware, operating systems (OSes), camera modules, microphones, and Universal Serial Bus (USB) input/output (I/O) components.

 

3. Industrial machinery: Embedded systems are prevalent within industrial machines, often in the form of sensors, and may even constitute the machinery itself. Industrial equipment frequently integrates embedded automation systems tasked with specific monitoring and control duties.

 

4. Medical equipment: Such equipment incorporates embedded systems featuring sensors and control mechanisms. Given the critical nature of medical applications, these systems necessitate a high degree of user-friendliness to mitigate potential risks to human health arising from machine errors. Consequently, they often incorporate sophisticated operating systems and graphical user interfaces tailored to ensure an appropriate user experience.

 

How do embedded systems operate?

 

Embedded systems invariably operate within a comprehensive apparatus, embodying the essence of being "embedded." These systems, characterized by their cost-effectiveness, minimal power consumption, and compactness, serve as miniature computing units integrated into broader mechanical or electrical frameworks. Typically, they encompass essential components such as a processor, power supply unit, memory, and communication interfaces. Utilizing these communication interfaces, embedded systems facilitate the exchange of data between the processor and peripheral devices, often including other embedded systems, employing standardized communication protocols. Subsequently, the processor deciphers this data with the aid of concise software stored in the memory. Notably, the software is meticulously tailored to fulfill the specific function entrusted to the embedded system.

 

The processor utilized within embedded systems may either be a microprocessor or a microcontroller. Microcontrollers are essentially microprocessors augmented with integrated memory and peripheral interfaces. In contrast, microprocessors rely on separate integrated circuits for memory and peripherals, rather than incorporating them directly onto the chip. While both options are viable, microprocessors typically demand more auxiliary circuitry due to their lesser degree of integration compared to microcontrollers. The term "system on a chip" (SoC) is frequently employed in this context. SoCs encompass multiple processors and interfaces within a single chip, making them particularly suitable for high-volume embedded systems. Examples of SoC variants include application-specific integrated circuits (ASICs) and field-programmable gate arrays (FPGAs).

 

Embedded systems frequently operate within real-time environments, necessitating the utilization of a real-time operating system (RTOS) to interface with the hardware. In scenarios where real-time demands are slightly relaxed, designers often opt for near-real-time approaches, leveraging the increased capabilities of modern chips. In such cases, simplified iterations of operating systems like Linux are commonly deployed. Nonetheless, other operating systems have been streamlined to run on embedded systems, including Embedded Java and Windows IoT (formerly Windows Embedded).

 

Attributes of embedded systems

 

The primary attribute defining embedded systems is their task-specific nature.

 

Moreover, embedded systems may encompass the following attributes:

 

• typically composed of hardware, software, and firmware components;
• integrated into larger systems to fulfill specific functions, focusing on specialized tasks rather than multitasking;
• employ either microprocessor-based or microcontroller-based architectures, both of which provide computational capabilities to the system;
• frequently utilized for sensing and real-time computing in internet of things (IoT) devices, which are internet-connected gadgets requiring minimal user intervention;
• exhibit varying levels of complexity and functionality, influencing the selection of software, firmware, and hardware components;
• often mandated to execute tasks within specified time constraints to ensure the seamless operation of the overarching system.

 

Composition of embedded systems

 

Embedded systems exhibit varying degrees of complexity, but typically incorporate three primary components:

 

1. Hardware: The hardware framework of embedded systems revolves around microprocessors and microcontrollers. Microprocessors, akin to microcontrollers, typically encompass a central processing unit (CPU) integrated with additional fundamental computing elements like memory chips and digital signal processors (DSPs). Microcontrollers consolidate these components within a single chip.

 

2. Software and firmware: Software utilized in embedded systems can vary in sophistication. However, industrial-grade microcontrollers and embedded IoT systems commonly operate on streamlined software requiring minimal memory resources.

 

3. Real-time operating system (RTOS): While not universally present in embedded systems, particularly in smaller-scale implementations, RTOSes play a crucial role in governing system behavior by overseeing software operations and enforcing rules throughout program execution.

 

Regarding hardware configuration, a fundamental embedded system typically comprises the following constituents:

 

- Sensors: These devices transform physical sensory input into electrical signals.

- Analog-to-digital (A-D) converters: Responsible for converting analog electrical signals into digital format.

- Processors: Execute digital signal processing tasks and store data in memory.

- Digital-to-analog (D-A) converters: Convert digital data from the processor into analog signals.

- Actuators: Compare actual output against memory-stored output and select the appropriate response.

 

The sensor captures external inputs, while the converters facilitate the translation of this input into a format intelligible to the processor. Subsequently, the processor processes this information to generate meaningful output for the embedded system.

 

Types of embedded systems

 

Embedded systems encompass several fundamental types, each tailored to specific functional requisites. They include:

 

1. Mobile embedded systems: Compact systems designed for portability, exemplified by devices like digital cameras.

 

2. Networked embedded systems refer to embedded systems that are interconnected with a network, facilitating the exchange of data and providing output to other systems. This configuration is commonly observed in applications such as home security systems and point of sale (POS) systems.

 

3. Standalone embedded systems: Autonomous systems performing specialized tasks without reliance on a host system. For instance, calculators or MP3 players operate independently.

 

4. Real-time embedded systems: Vital for time-sensitive tasks in sectors like medical, industrial, and military, ensuring timely output delivery. A traffic control system exemplifies this category.

 

Embedded systems can further be classified based on their performance requisites:

 

- Small-scale embedded systems typically employ 8-bit microcontrollers.

- Medium-scale embedded systems utilize larger microcontrollers (16-32 bit) and may involve interlinked microcontrollers.

- Sophisticated-scale embedded systems integrate diverse algorithms, resulting in intricate software and hardware complexities. They may necessitate advanced software, configurable processors, and/or programmable logic arrays.

 

Moreover, as embedded systems evolve in complexity, various software architectures become indispensable. These include:

 

- Simple control loops, delegating tasks to subroutines managing specific hardware or embedded programming aspects.

- Interrupt controlled systems featuring primary and secondary loops, with interruptions triggering designated tasks.

- Cooperative multitasking, wherein a straightforward control loop resides in an application programming interface (API).

- Preemptive multitasking or multithreading, often employed alongside a real-time operating system (RTOS), characterized by synchronization and task-switching mechanisms.

 

Very large-scale integration (VLSI) denotes the intricate complexity of an integrated circuit (IC). In the realm of semiconductor technology, VLSI entails the embedding of hundreds of thousands of transistors onto a single chip. Contrasted with this, LSI (large-scale integration) microchips accommodate thousands of transistors, MSI (medium-scale integration) incorporates hundreds of transistors, and SSI (small-scale integration) comprises tens of transistors. Ultra-large-scale integration (ULSI) extends this concept further by accommodating millions of transistors within a single chip.

 

Embedded systems frequently feature VLSI circuits, with numerous ICs in such systems adopting VLSI architectures. However, the widespread use of the VLSI acronym has diminished over time.

 

Debugging embedded systems

 

Debugging embedded systems diverges from the practices employed in the operating systems and development environments of larger-scale computers. Typically, developers working within desktop computer environments have the luxury of running both the code under development and separate debugger applications that can monitor the system's behavior. In contrast, embedded system programmers often lack this capability.

 

Certain programming languages exhibit sufficient efficiency to enable rudimentary interactive debugging directly on microcontrollers. Moreover, processors often feature CPU debuggers accessible via a JTAG or similar debugging port, granting control over program execution.

 

However, in many cases, programmers necessitate tools that connect a separate debugging system to the target system via a serial or alternative port. In this setup, the programmer can view the source code on the display of a general-purpose computer, akin to debugging software on a desktop computer. Another prevalent approach involves running software on a PC that emulates the physical chip in software, facilitating debugging as if it were executed on an actual physical chip.

 

In general, embedded systems have garnered heightened attention regarding testing and debugging due to the extensive utilization of embedded controls in devices, particularly in environments prioritizing safety and reliability.

 

 History of embedded systems

 

The inception of embedded systems can be traced back to the 1960s. Charles Stark Draper's development of an integrated circuit in 1961 marked a pivotal moment, aimed at minimizing the size and weight of the Apollo Guidance Computer. This digital system, installed on the Apollo Command Module and Lunar Module, was the first computer to leverage ICs, facilitating real-time flight data collection for astronauts.

 

In 1965, Autonetics, now under Boeing, introduced the D-17B, utilized in the Minuteman I missile guidance system, earning distinction as the inaugural mass-produced embedded system. Subsequently, with the advent of the Minuteman II in 1966, the D-17B was supplanted by the NS-17 missile guidance system, renowned for its extensive integration of ICs. The automotive sector witnessed a significant milestone in 1968 with the debut of the first embedded system for a vehicle: the Volkswagen 1600, leveraging a microprocessor to govern its electronic fuel injection system.

 

As integrated circuit prices plummeted in the late 1960s and early 1970s, their prevalence surged. Texas Instruments' development of the first microcontroller in 1971 marked a watershed moment. The TMS1000 series, commercially available in 1974, featured a 4-bit processor, coupled with read-only memory (ROM) and random-access memory (RAM), each unit priced at approximately $2 in bulk orders.

 

Simultaneously, in 1971, Intel launched the groundbreaking 4004, widely regarded as the first commercially accessible processor. Designed for calculators and small electronics, it relied on external memory and support chips. Intel's subsequent release, the 8-bit 8008 in 1972, boasted 16 KB of memory, followed by the 64 KB-equipped Intel 8080 in 1974. The introduction of the x86 series in 1978 represented a significant evolution, remaining prevalent in contemporary usage.

 

The emergence of embedded operating systems in 1987 with Wind River's real-time VxWorks, followed by Microsoft's Windows Embedded CE in 1996, marked pivotal milestones. By the late 1990s, the advent of the first embedded Linux products commenced, eventually establishing Linux as a ubiquitous presence in nearly all embedded devices.

 

Embedded system trends

 

Embedded systems are undergoing a notable evolution, transitioning from relatively simple configurations to increasingly intricate setups. Moreover, a growing number of embedded systems exhibit capabilities surpassing human decision-making or offer functionalities exceeding human capacities. For instance, aviation systems utilized in drones can process sensor data and enact responses at speeds beyond human capability, introducing novel operational features.

 

The trajectory of embedded systems is poised for rapid expansion, largely propelled by the burgeoning realm of the internet of things (IoT). The proliferation of IoT applications, spanning wearables, drones, smart homes, smart buildings, video surveillance, 3D printers, and smart transportation, is anticipated to galvanize the growth of embedded systems.