Embedded Systems Quiz

Study Notes

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.

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

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.

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.

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.

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

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.

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).

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.

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.

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.

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).