Lecture 1 - Introduction to ARM assembly language Flashcards
What is an embedded system?
A device that includes a programable computer, but is not itself a general purpose computer.
A computing system, specialized for only few applications with none (or few) end user programmability, embedded into a larger product
The main purpose of embedded systems are not computing
Name a few examples of embedded systems
Washing machine
a car
smart homes
air craft
Define Cyber-physical systems
A term that defines there being a physical world and a digital one.
How are embedded systems connected to the term Cyber-physical?
An embedded system observes something in the physical world, and processes information and does computing in the digital one, and based on computation deside how to influence the physical world
What are the key design objectives when designing embedded systems
Predictability
Dependability
Efficiency
Define predictability as a design objective for embedded systems
It is essential to predict how the CPS (cyber-physical system) will behave under any circumstances and conditions, before the system is deployed. This is due to the fact that the system will influence the physical world, and thereby needs to be safe in any situation.
Define efficiency as a design objective for embedded systems
CPSs should be energy and run-time efficient, and weight and cost efficient.
Define dependability as a design objective for embedded systems
CPSs must operate dependable, safely, securely, efficiently in real time. They must operate as you would expect in any situation.
Name properties of embedded systems
Reactive
Time constrained
Specialized
Define reactive-ness as a property of embedded systems
As the physical world constantly changes, an embedded system must be highly reactive to these changes.
Must react to stimuli for environment.
The rate of reaction is defined by the rate in which the environment is changing, and the embedded system should be able to keep pace with this rate
Define time constraint as a property of embedded systems
Embedded systems must do computation and action within a certain real-time constraints.
As embedded systems does computations based on real world observations, if the answers arrives too late they would already be wrong as they are would no longer be useful.
Define specialized as a property of embedded systems
Embedded systems are sepcialized towards a few applications or domains, and does little less.
Domain knowledge helps optimize design and resource use, maximize predictability etc.
What are the differences of embedded- and general purpose systems
Embedded systems are specialized and have few applications (these are known at design time). General purpose systems have a broad range of applications. You might not know in advanced what the general computer will be used for, but it should still be able to execute applications and programs as they arrive.
Embedded systems are not programmable by the end user, where as general purpose systems are.
Embedded systems have fixed performance requirements. Additional performance is not necessarily useful. High performance in general purpose systems are useful to allow additional new applications.
Both embedded- and general purpose systems have cost and power consumptions as design criteria. However, when it comes to speed, what matters in embedded systems are the worst case speed, and in GPS are the avarage speed. Embedded systems also need to take into account size, weight and dependability.
Name the 5 stages in the design flow of embedded systems
Requirements
Specification (technical details)
Architecture (what are the components, and how are these connected)
Components (design of individual components)
Integration (Connect all components and make them work together)
Define a top-down design
When starting at the requirements and working the way to integration.
