EMBEDDED SYSTEM
Covered Topics: Introduction to Embedded System: What is Embedded System, Embedded Systems Vs General Computing Systems, History, classification, major application areas and purpose of Embedded Systems, Wearable Devices. The Typical Embedded System: Core of the Embedded System, Memory.
UNIT 1: Introduction to Embedded System:
What is Embedded System
Embedded Systems Vs General Computing Systems
Embedded systems and general computing systems (like personal computers or servers) serve different purposes and have distinct characteristics. Here are some key differences between embedded systems and general computing systems:
1. Functionality and Purpose:
- Embedded Systems: Designed for specific, dedicated functions within a larger system or device. Examples include controlling the engine in a car, managing the display in a washing machine, or regulating the temperature in a thermostat.
- General Computing Systems: Built for versatility and the ability to run a wide range of applications. Examples include personal computers, laptops, servers, and workstations.
2. Flexibility:
- Embedded Systems: Typically have fixed functionality. Changes or updates often require hardware or firmware modifications.
- General Computing Systems: Highly flexible and can run a variety of software applications. Users can install, update, and change software to meet different needs.
3. Resource Constraints:
- Embedded Systems: Operate under resource constraints such as limited processing power, memory, and storage. These constraints are often due to size, cost, and power limitations.
- General Computing Systems: Have more abundant resources, allowing them to handle complex tasks and run resource-intensive applications.
4. Real-Time Operation:
- Embedded Systems: Many embedded systems operate in real-time, meaning they must respond to inputs or events within a specific timeframe. This is critical for applications like automotive control systems or medical devices.
- General Computing Systems: While some systems can handle real-time tasks, general-purpose computers are not always designed with strict real-time requirements.
5. User Interaction:
- Embedded Systems: Often have limited or no direct user interaction. Users may interact with the larger device or system that the embedded system is a part of.
- General Computing Systems: Designed for user interaction and can include interfaces like keyboards, mice, touchscreens, and graphical user interfaces (GUIs).
6. Examples:
- **Embedded Systems:** Found in everyday devices and appliances like washing machines, thermostats, microwave ovens, smart TVs, and automotive control systems.
- **General Computing Systems:** Include personal computers, laptops, servers, workstations, and other devices capable of running a wide range of applications.
In summary, embedded systems are specialized, task-specific computing systems integrated into larger devices or systems, while general computing systems are versatile devices designed for a broad range of applications with greater flexibility and resources.
Major application areas and purpose of Embedded Systems
Embedded systems find applications in a wide range of industries and play a crucial role in various aspects of modern life. Here are some major application areas and purposes of embedded systems:
1. **Consumer Electronics:**
- *Purpose:* Embedded systems are used in devices such as smart TVs, digital cameras, washing machines, refrigerators, and home automation systems to control and manage specific functions.
2. **Automotive Systems:**
- *Purpose:* Embedded systems control various aspects of vehicles, including engine management, anti-lock braking systems (ABS), airbag systems, navigation systems, entertainment systems, and advanced driver assistance systems (ADAS).
3. **Industrial Automation:**
- *Purpose:* Embedded systems are integral to industrial control systems, programmable logic controllers (PLCs), and supervisory control and data acquisition (SCADA) systems. They help automate manufacturing processes, monitor equipment, and optimize efficiency.
4. **Medical Devices:**
- *Purpose:* Embedded systems are used in medical equipment such as infusion pumps, pacemakers, blood glucose monitors, and imaging devices to control and monitor patient health.
5. **Communication Systems:**
- *Purpose:* Embedded systems are employed in communication devices, including routers, modems, mobile phones, and network switches, to manage data transfer, signal processing, and network protocols.
6. **Aerospace and Defense:**
- *Purpose:* Embedded systems are crucial in avionics, navigation systems, radar systems, unmanned aerial vehicles (UAVs), and other defense applications for controlling and monitoring various functions.
7. **Smart Grids and Energy Management:**
- *Purpose:* Embedded systems contribute to the automation and control of smart grids, energy monitoring systems, and renewable energy systems to optimize energy consumption and distribution.
8. **IoT (Internet of Things):**
- *Purpose:* Embedded systems form the backbone of IoT devices, connecting physical objects to the internet. They are used in applications like smart home devices, industrial IoT, and wearable technology.
9. **Embedded Software Development:**
- *Purpose:* Embedded systems often require specialized software development to create firmware and software that run on microcontrollers or microprocessors. This includes real-time operating systems (RTOS) and low-level programming.
10. **Security Systems:**
- *Purpose:* Embedded systems are used in security and surveillance systems, including CCTV cameras, access control systems, and alarm systems, to monitor and respond to security events.
11. **Networking Equipment:**
- *Purpose:* Routers, switches, and other networking equipment utilize embedded systems to manage data traffic, implement network protocols, and ensure the efficient functioning of communication networks.
12. **Automated Control Systems:**
- *Purpose:* Embedded systems are employed in various automated control systems, including home automation, industrial control, and robotics, to perform specific tasks and respond to environmental stimuli.
These applications demonstrate the versatility and importance of embedded systems across a wide range of industries, contributing to the efficiency, functionality, and automation of diverse technologies.
Wearable Devices
Wearable devices are electronic devices that are designed to be worn on the body, often as accessories or as part of clothing. These devices are equipped with sensors, processors, and communication capabilities, and they are designed to perform various functions to enhance the user's experience and provide valuable information. Here are some common types and purposes of wearable devices:
1. **Smartwatches:**
- *Purpose:* Smartwatches offer functionalities beyond traditional timekeeping. They often include fitness tracking, heart rate monitoring, notifications for calls and messages, and even the ability to run third-party apps.
2. **Fitness Trackers:**
- *Purpose:* Fitness trackers, also known as activity trackers, monitor physical activity, including steps taken, distance traveled, calories burned, and sleep patterns. They are commonly used for health and wellness tracking.
3. **Smart Glasses:**
- *Purpose:* Smart glasses display information directly to the user, often in the form of augmented reality (AR) overlays. They can provide hands-free access to information, navigation, and communication.
4. **Health Monitoring Devices:**
- *Purpose:* These devices monitor various health metrics such as heart rate, blood pressure, blood glucose levels, and more. They can be used for personal health tracking or for medical monitoring in certain situations.
5. **Wearable Cameras:**
- *Purpose:* Cameras integrated into wearable devices, such as body cameras for law enforcement or action cameras for sports enthusiasts, capture first-person perspectives or specific events.
6. **Smart Clothing:**
- *Purpose:* Clothing with embedded sensors can monitor body movements, temperature, and other physiological parameters. This data can be used for health monitoring, fitness tracking, or even in sports training.
7. **Smart Jewelry:**
- *Purpose:* Jewelry with embedded technology can track various metrics or provide discreet notifications. Examples include smart rings that monitor sleep patterns or bracelets that track fitness activities.
8. **Wearable ECG Monitors:**
- *Purpose:* Some wearable devices are designed specifically to monitor the electrocardiogram (ECG or EKG) of the user, providing insights into heart health and detecting irregularities.
9. **Virtual Reality (VR) and Augmented Reality (AR) Headsets:**
- *Purpose:* While not strictly worn throughout the day, VR and AR headsets are wearable devices that immerse users in virtual or augmented environments, offering applications in gaming, education, training, and more.
10. **Children and Elderly Tracking Devices:**
- *Purpose:* Wearable devices designed for tracking the location and well-being of children or elderly individuals. These devices often include GPS functionality and communication features.
11. **Hearables:**
- *Purpose:* Hearables include devices like smart earbuds that not only provide audio but also incorporate features such as fitness tracking, health monitoring, and voice assistants.
Wearable devices have gained popularity due to their convenience, portability, and ability to seamlessly integrate technology into everyday life. They contribute to the growing trend of the Internet of Things (IoT) and the increasing emphasis on personal health and fitness monitoring.
The Typical Embedded System:
A typical embedded system comprises several key components that work together to perform specific functions within a larger device or system. Here are the typical components found in an embedded system:
1. **Microcontroller/Microprocessor:**
- *Function:* The central processing unit (CPU) of the embedded system. It executes instructions and controls the operation of the system. Microcontrollers are often used in embedded systems due to their integration of a CPU, memory, and peripherals on a single chip.
2. **Memory:**
- *Function:* Stores program instructions and data for the embedded system.
- *Types:*
- **Flash Memory:** Non-volatile memory used for storing the program code.
- **RAM (Random Access Memory):** Volatile memory used for temporary data storage during operation.
3. **Input Devices:**
- *Function:* Collects data or user inputs for the embedded system.
- *Examples:*
- Sensors (e.g., temperature sensors, accelerometers, gyroscopes)
- Analog-to-digital converters (ADCs)
- Digital interfaces (e.g., USB, UART, I2C)
4. **Output Devices:**
- *Function:* Displays information or provides outputs to the user or other systems.
- *Examples:*
- Display screens (e.g., LCD, LED)
- Actuators (e.g., motors, solenoids)
- Digital-to-analog converters (DACs)
5. **Communication Interfaces:**
- *Function:* Facilitates communication with other devices or systems.
- *Examples:*
- UART (Universal Asynchronous Receiver-Transmitter)
- SPI (Serial Peripheral Interface)
- I2C (Inter-Integrated Circuit)
- Ethernet, Wi-Fi, Bluetooth for wireless communication
6. **Real-Time Clock (RTC):**
- *Function:* Keeps track of time in real-time applications and helps timestamp events.
- *Use Cases:* Time-sensitive applications, data logging, scheduling.
7. **Power Supply:**
- *Function:* Provides the necessary power for the embedded system to operate.
- *Types:*
- **Battery:** Common in portable devices.
- **External Power Source:** Plugged into a power outlet.
8. **Operating System or Firmware:**
- *Function:* Manages the execution of software and provides a platform for applications to run.
- *Types:*
- **Real-Time Operating System (RTOS):** Used in time-sensitive applications.
- **Firmware:** Low-level software embedded in hardware, often specific to the device.
9. **Watchdog Timer:**
- *Function:* Monitors the operation of the system and resets it in case of malfunctions or failures.
10. **Enclosure/Physical Packaging:**
- *Function:* Protects the embedded system components from environmental factors and physical damage.
These components work together to form a cohesive embedded system that performs specific tasks or functions within a larger context. The design of embedded systems varies widely based on the application requirements, and customization is common to meet the specific needs of the device or system in which they are embedded.
Core of the Embedded System
The core of an embedded system typically refers to the central processing unit (CPU), which is responsible for executing instructions and controlling the overall operation of the system. The CPU is the primary component that performs computations, processes data, and manages the flow of instructions within the embedded system.
In the context of embedded systems, there are two main types of cores that can serve as the CPU:
1. **Microcontroller Core:**
- *Description:* Microcontrollers are compact integrated circuits that combine a CPU core with other essential components such as memory (both flash memory for program storage and RAM for data storage), input/output peripherals, timers, and communication interfaces.
- *Purpose:* Microcontrollers are commonly used in embedded systems that require a low-power, cost-effective solution with relatively simple processing needs. They find applications in a wide range of devices, including household appliances, automotive control systems, and consumer electronics.
2. **Microprocessor Core:**
- *Description:* Microprocessors are more powerful and versatile than microcontrollers. They focus primarily on processing data and executing instructions. Unlike microcontrollers, microprocessors may require external components such as memory, input/output peripherals, and communication interfaces to form a complete embedded system.
- *Purpose:* Microprocessors are often chosen for embedded systems that demand higher computational power and more complex functionalities. Applications include industrial automation, medical devices, and sophisticated consumer electronics.
In both cases, the core of the embedded system plays a central role in determining the system's processing capabilities, power efficiency, and overall performance. The choice between a microcontroller and a microprocessor depends on the specific requirements of the application, considering factors such as power consumption, cost, processing speed, and the complexity of tasks to be performed.
Memory:
Memory in embedded systems refers to the storage and retrieval of data, instructions, and other information required for the proper functioning of the system. Memory is a critical component in embedded systems, and it can be broadly categorized into two main types: program memory and data memory.
1. **Program Memory:**
- *Purpose:* Program memory, also known as code memory, is used to store the instructions that the embedded system's central processing unit (CPU) executes. These instructions form the program or firmware that defines the behavior and functionality of the embedded system.
- *Types:*
- **Flash Memory:** Commonly used for program storage in embedded systems. It is non-volatile, meaning it retains data even when power is removed. Flash memory is suitable for storing the firmware or software that runs on the system.
- **Read-Only Memory (ROM):** In some cases, embedded systems use ROM to store fixed and unchangeable instructions. Unlike flash memory, ROM is typically not rewritable.
2. **Data Memory:**
- *Purpose:* Data memory is used to store temporary data that the CPU manipulates during program execution. This includes variables, intermediate results, and other information that changes dynamically during the system's operation.
- *Types:*
- **Random Access Memory (RAM):** This is volatile memory used for temporary data storage. RAM is fast and allows for both read and write operations. However, it loses its content when power is turned off. In embedded systems, RAM is used for tasks such as storing variables, buffers, and stack space.
- **Static Random Access Memory (SRAM):** A type of RAM that does not need to be periodically refreshed and is often faster than other types of RAM. SRAM is used when speed and power consumption are critical factors.
Memory management in embedded systems is crucial for efficient operation. The size and type of memory impact the system's performance, power consumption, and overall cost. In some cases, embedded systems may have multiple levels of memory hierarchy, including caches for faster access to frequently used data.
Additionally, memory considerations in embedded systems may include the use of memory-mapped peripherals, where certain memory addresses are assigned to control and communicate with peripheral devices. This allows the CPU to interact with peripherals using standard memory read and write operations.
The choice of memory architecture and type depends on factors such as the application requirements, power constraints, cost considerations, and the desired performance of the embedded system.
Classification
In the context of embedded systems, classification refers to the categorization of different types of embedded systems based on various criteria such as their functionality, performance, power requirements, and application domains. Embedded systems can be classified in several ways, and here are some common classifications:
1. **Based on Performance and Complexity:**
- **Simple Embedded Systems:** These systems perform basic functions and are often single-purpose devices with limited computational power and resources. Examples include simple microcontroller-based systems found in household appliances.
- **Complex Embedded Systems:** These systems are more powerful and capable, often incorporating microprocessors or specialized processors. They can handle complex tasks and run sophisticated applications. Examples include automotive control systems and industrial automation.
2. **Based on Functionality:**
- **Stand-Alone Embedded Systems:** These systems operate independently and perform specific functions without relying on other devices or networks. Examples include a standalone washing machine controller.
- **Networked Embedded Systems:** These systems are interconnected and communicate with other devices or systems. They are often part of larger networks, contributing to the Internet of Things (IoT). Examples include smart home devices and industrial IoT applications.
3. **Based on Performance Requirements:**
- **Real-Time Embedded Systems:** These systems have strict timing constraints, and the correctness of the system depends not only on the logical result but also on the time at which the results are produced. Examples include automotive control systems and medical devices.
- **Non-Real-Time Embedded Systems:** These systems do not have stringent timing requirements. While they may have performance goals, missing a deadline does not necessarily result in system failure. Examples include consumer electronics and some industrial automation systems.
4. **Based on Power Consumption:**
- **Low-Power Embedded Systems:** These systems are designed to operate with minimal power consumption, often using techniques such as power gating, sleep modes, and energy-efficient components. Examples include battery-operated devices like wearables and sensor nodes.
- **High-Performance Embedded Systems:** These systems may prioritize processing power over power efficiency and are designed to handle computationally intensive tasks. Examples include multimedia processing systems and advanced robotics.
5. **Based on Application Domain:**
- **Automotive Embedded Systems:** Found in vehicles for functions like engine control, safety systems, and infotainment.
- **Medical Embedded Systems:** Used in medical devices such as patient monitors, infusion pumps, and diagnostic equipment.
- **Consumer Electronics Embedded Systems:** Found in everyday devices like smartphones, smart TVs, and home appliances.
6. **Based on Processing Architecture:**
- **Microcontroller-Based Systems:** Use microcontrollers for processing and typically have integrated peripherals. Common in simple embedded applications.
- **Microprocessor-Based Systems:** Use microprocessors and may require external components for additional functionalities. Common in more complex embedded applications.
These classifications help in understanding the diverse nature of embedded systems and aid in selecting appropriate design approaches and technologies based on the specific requirements of the application.
