Embedded Systems Quiz

Software Development for Embedded and Realtime Systems

• Embedded systems combine hardware and software to perform specific functions.
• These systems operate in reactive and time-constrained environments.
• They respond to the surroundings via sensors and control the environment using actuators.
• Real-time systems have hard and soft real-time distinctions. Hard real-time systems have strict deadlines, whereas soft real-time systems have flexible deadlines.
• Multi-rate systems can handle multiple processing rates.

Course Objectives

• Key software development phases for embedded systems include problem definition, architecture development, design development, implementation (component-based), verification, and validation.

What is an Embedded System?

• Embedded systems are combinations of hardware and software to form a computational engine performing specific tasks.
• They operate in both reactive and time-constrained environments.
• Systems respond to the environment via sensors and manage the environment by using actuators.
• Real-time systems differentiate between hard (strict deadlines) and soft (flexible deadlines).
• Multi-rate systems can handle multiple processing rates.

Typical Embedded System

• Components include sensors, processor cores, memory, analog I/O, emulation/diagnostics, software/firmware, user interface, power, and cooling, and actuators. Components are interconnected to achieve desired system functionality.
• Application-specific gates process information gathered by sensors.

Abstract Model of an Embedded System

• Embedded systems connect to other systems (wireless/network).
• Sensors process input, converting energy and conditioning the signal.
• A computer makes the necessary decisions.
• This leads to Actuation, with the computer's decisions being transmitted (power modulation) to the physical system.
• Actuation impacts the physical system (mechanical/electrical)
• Feedback loops to the human machine interface and human factors complete the model.

Example Embedded System

• An example system handles flow sensor data, processes it (computation), and outputs valve angle control signals, enabling a control loop.

Hard vs Soft Real Time

• Hard real-time systems have a direct relationship between cost and time to deadline.
• Soft real-time systems have cost more indirectly related to deadline.

Examples of Hard and Soft Real Time Systems

• Systems categorized as hard or soft real-time based on their criticality.
• Examples include traffic lights (hard real-time), ATM machines (soft real-time), and car simulators (hard real-time).

Hard Real Time Safety Critical System

• Safety-critical systems such as automotive systems demand that the system responds according to a preset protocol to avoid accidents.
• The system monitors and accounts for drivers intentions and driving conditions to enable smooth gear shifting in real-time.

Real-time vs Time-shared

• Time-shared systems prioritize high throughput and fast average response times, ensuring fairness to all users.
• Real-time systems prioritize schedulability and task predictability, ensuring important tasks fulfill deadlines, even under overload.

Real-time System Constraints

• Hard real-time systems define deadlines in various ways (microseconds to weeks).
• Real-time tasks and execution environments should accommodate schedule and resource allocation to meet deadlines.

Real-time Event Categories

• Asynchronous events are unpredictable (e.g., cellphone call arrival).
• Synchronous events occur regularly (e.g., video streaming).
• Isochronous events occur within defined time windows (e.g., audio in a video stream).

References

• Oshana's "Software Engineering for Embedded Systems" (2013) provides relevant information and context.

Test your knowledge on software development for embedded and real-time systems. This quiz covers key concepts such as system architecture, real-time distinctions, and multi-rate processing. Discover how embedded systems interact with their environments through sensors and actuators.