3.1.5 | COMPUTER ARCHITECTURE

Topics from the Cambridge IGCSE (9-1) Computer Science 0984 syllabus 2023 - 2025.

OBJECTIVES
3.1.5 Describe the purpose and characteristics of an embedded system and identify devices in which they are commonly used
An embedded system is used to perform a dedicated function, e.g. domestic appliances, cars, security systems, lighting systems or vending machines. This is different to a general purpose computer that is used to perform many different functions, e.g. a personal computer (PC) or a laptop

ALSO IN THIS TOPIC
3.1.1 COMPUTER ARCHITECTURE 
3.1.2 COMPUTER ARCHITECTURE 
​3.1.3 COMPUTER ARCHITECTURE 
​3.1.4 COMPUTER ARCHITECTURE 
YOU ARE HERE | ​3.1.5 COMPUTER ARCHITECTURE 
3.2.1 INPUT AND OUTPUT DEVICES 
3.2.2 INPUT AND OUTPUT DEVICES 
3.2.3 INPUT AND OUTPUT DEVICES
3.3 DATA STORAGE 
3.4 NETWORK HARDWARE 
REVISION CARDS
TOPIC 3 KEY TERMINOLOGY
TOPIC 3 ANSWERS
TOPIC 3 TEACHER RESOURCES
TOPIC 1 TEACHER RESOURCES (CIE)

EMBEDDED SYSTEMS

Embedded systems are computer systems that are designed to perform specific functions or tasks within a larger system or product. They are typically small, low-power devices that are integrated into larger systems and operate independently or with minimal human intervention. They often operate in real-time environments and require fast and deterministic responses to external events. They may also have limited resources, such as memory, processing power, and energy, and must be designed to operate reliably and efficiently under these constraints.

Embedded systems can be programmed using a variety of programming languages and development tools, depending on the specific requirements of the system. Common programming languages used for embedded systems include C, C++, and assembly language.

EMBEDDED SYSTEMS VS GENERAL PURPOSE COMUPTERS

​Embedded systems and general-purpose computers are two different types of computing systems with distinct designs and characteristics. An embedded system is a computer system designed to perform specific functions or tasks within a larger system or product. They are typically small, low-power devices that are integrated into larger systems and operate independently or with minimal human intervention. Embedded systems often operate in real-time environments and require fast and deterministic responses to external events. They may also have limited resources, such as memory, processing power, and energy, and must be designed to operate reliably and efficiently under these constraints. Embedded systems are used in a wide range of applications such as automotive, medical, industrial control, and consumer electronics.

On the other hand, a general-purpose computer is designed to perform a wide range of tasks and are built to be flexible and adaptable to different software and hardware configurations. General-purpose computers are characterized by their flexibility, high processing power, large memory, and ability to run a wide range of software applications. They are often used for office work, gaming, web browsing, and other general-purpose computing tasks. Unlike embedded systems, general-purpose computers are not optimized for a specific function or application and are not typically built as part of a larger system or product. They are designed to provide a user-friendly computing interface that allows users to run a variety of applications and perform different tasks with the same system.

EXAMPLES IN EVERYDAY LIFE

Some examples of how embedded systems are used in various devices:

• Washing machine: Modern washing machines use embedded systems to control various functions such as water inlet, water temperature, wash cycle, spin cycle, and drying. The embedded system controls these functions by using sensors to detect the level of water, temperature, and weight of clothes, and then executing the appropriate program.
• Automatic lighting systems: Embedded systems are used in automatic lighting systems to detect the presence of people in a room or area and to adjust the lighting accordingly. The system uses sensors such as infrared or ultrasonic sensors to detect movement and then activates or deactivates the lights based on the presence of people.
• Air conditioning: Embedded systems are used in air conditioning systems to regulate temperature, humidity, and air quality. The system uses sensors to detect the temperature and humidity levels and then activates or deactivates the air conditioning system accordingly.
• Cooker: Modern cookers use embedded systems to control various functions such as temperature, time, and cooking mode. The embedded system controls these functions by using sensors to detect the temperature of the food and then executing the appropriate program.
• Vending machine: Embedded systems are used in vending machines to control the dispensing of products and to manage inventory. The system uses sensors to detect the payment and then activates the dispensing mechanism to deliver the selected product.
• Traffic lights: Traffic lights use embedded systems to control the timing and sequencing of traffic signals. The system uses sensors to detect the presence of vehicles and pedestrians and then adjusts the timing of the traffic lights accordingly.
• Cars: Cars use embedded systems to control various functions such as engine management, anti-lock braking systems (ABS), and airbags. The embedded system controls these functions by using sensors to detect the vehicle speed, engine temperature, and other factors, and then executing the appropriate program.

Embedded systems are used in various devices and systems to control and automate their functions, making them more efficient, reliable, and convenient.

INPUT | PROCESS | OUTPUT

Every embedded system has an input, process, and output. The input is the data or signals that the system receives from sensors or other sources. The process is the computation or manipulation of the input data using software and the microprocessors. The output is the result or action produced by the system, which may include controlling motors, displaying information, or communicating with other devices.

Take a washing machine as an example:
The washing machine's input comes from the user, who selects the wash settings they want. Inputs also come from sensors that detect the water level and temperature, which are then converted from an analogue signal to digital using an analogue-to-digital converter (ADC). The process receives these inputs and checks them against set values, such as the desired water temperature and the appropriate wash cycle. The processor then sends a signal to output devices, such as actuators that control the motor or heat rods, to make changes as needed. The processor is in a loop that continuously monitors the sensors and the outputs, making changes as necessary to complete the wash cycle. Ultimately, the output is the clean clothes that are ready to be dried and worn.

The above explanation of the process of a washing machine forms a good basis for answering an examination style question, the highlighted key terms used can be used in similar questions.

BENEFITS AND DRAWBACKS OF EMBEDDED SYSTEMS

BENEFITS

• Efficient performance: Embedded systems are highly optimized for specific tasks, making them more efficient and faster than general-purpose computers in performing these tasks.
• Low power consumption: Embedded systems are designed to use minimal power, making them ideal for applications that require long battery life or operate on low power sources.
• Real-time operation: Embedded systems are often used in applications that require real-time operation, such as automotive control, medical devices, and industrial automation.
• High reliability: Embedded systems are designed to operate reliably and continuously for long periods without failure, making them ideal for critical applications.
• Cost-effective: Embedded systems are often designed to use low-cost components, making them cost-effective for high-volume production.

DRAWBACKS

• Limited resources: Embedded systems often have limited resources such as memory, processing power, and energy, which can constrain their functionality and performance.
• Lack of flexibility: Embedded systems are designed to perform specific tasks, which can make them less flexible than general-purpose computers in adapting to changing requirements or applications.
• Difficult to program: Embedded systems often require low-level programming languages and specialized development tools, making them more challenging to program and maintain than general-purpose computers.
• Security vulnerabilities: Embedded systems can be vulnerable to security threats, especially if they are connected to the internet or other networks.
• Maintenance challenges: Embedded systems can be difficult to repair or maintain, especially if they are integrated into a larger system or product.

EXAMINATION STYLE QUESTION

​Explain the process by which an air conditioning unit maintains a steady temperature in a room. [6]

ALSO IN THIS TOPIC

3.1.1 COMPUTER ARCHITECTURE | The role of the CPU
3.1.2 COMPUTER ARCHITECTURE | Components of the CPU
3.1.3 COMPUTER ARCHITECTURE | Core's, Cache and Clock speed
3.1.4 COMPUTER ARCHITECTURE(CIE) | The Instruction Set
3.1.5 COMPUTER ARCHITECTURE | Embedded Systems
3.2.1 INPUT AND OUTPUT DEVICES | Input Devices
3.2.2 INPUT AND OUTPUT DEVICES | Output Devices
3.2.3 INPUT AND OUTPUT DEVICES | Sensors
3.3 DATA STORAGE | Primary, Secondary, Virtual and Cloud storage
3.4 NETWORK HARDWARE | Networks, Components and Protocols
REVISION CARDS | Flip cards to help test yourself
TOPIC 3 KEY TERMINOLOGY
TOPIC 3 ANSWERS
TOPIC 3 TEACHER RESOURCES