In this chapter, the following content will be discussed: Introduction, component technology in embedded systems, case study – ABB’s field devices, prerequisites for effective development of component-based embedded systems.
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Chapter 16 Component based embedded systems
Chapter 16
Component based embedded
systems
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Chapter 16 Component based embedded systems
Overview
Introduction
Component technology in embedded systems
Case study – ABB’s Field Devices
Prerequisites for effective development of based embedded systems
Component-Summary
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Chapter 16 Component based embedded systems
Where is the problem?
Huge market arises for embedded devices, and thus for software for them
Similar basic functionalities are repeated
New functionalities are added constantly
Shorter development time is required
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Chapter 16 Component based embedded systems
Introduction
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Chapter 16 Component based embedded systems
Component based SE can provide a
framework instead of technology
Embedded devices
are too small for
component offthe
shelf technologies
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Chapter 16 Component based embedded systems
Component technology in embedded world
Contractually specified interfaces
Component as a unit of composition and independent deployment
Explicit context dependencies
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Chapter 16 Component based embedded systems
Contractually specified interfaces
State-of-the-art technologies approach:
Interfaces as pure collection of methods.
• Embedded environment constraint:
Nonfunctional specifications are equally
important part of the contract
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Interfaces II
Component interfaces support:
Late binding, Polymorphism, Semantic specification
Pre conditions, Post conditions, Invariants
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Chapter 16 Component based embedded systems
Unit of composition and independent
deployment
Run-time composition
Component model, Run-time environment, Dynamic communication,
Design-time composition
Capable of generating monolithic firmware from component-based design, Optimization
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Chapter 16 Component based embedded systems
Explicit context dependencies
What is a context in embedded world?
Other components and interfaces
Run-time environment
CPU, RTOS, Component implementation language, Resource constraints
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Chapter 16 Component based embedded systems
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Chapter 16 Component based embedded systems
Reuse
Black-box reuse
From component’s user point of view,
White-box reuse
From composition environment point of view
Gray-box reuse (composition environment)
If clear conventions for knowledge about implementation are introduced
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Chapter 16 Component based embedded systems
Architecture and frameworks
Defining components alone will not lead to reuse
Common architecture for family of embedded devices Framework for development
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Chapter 16 Component based embedded systems
Portability, Platform independence
Source level portability suffices,
Design-time composition, Run-time environment restrictions
Source level portability requires:
Agreement on implementation language, Agreement on available libraries,
Providing proper abstractions (i.e RTOS API)
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Chapter 16 Component based embedded systems
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Chapter 16 Component based embedded systems
Case study – ABB’s Field devices
Synchronous approach
Architecture of the field devices
Dynamic behavior
Inter-component communication
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Chapter 16 Component based embedded systems
Synchronous approach
Synchronous languages have been developed to simplify
the programming of reactive systems
Provide the mean to handle concurrency, determinism, response time control
Based on synchrony hypothesis
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Chapter 16 Component based embedded systems
Architecture of the field device
POS_VALUE
FEEDBACK
Pos Control
Pos Measure.
I/O HW
CTRL_PAR
AO Algorithm
PC/Handheld-Interface
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Chapter 16 Component based embedded systems
manipulated variable (3)
Controlled System actual
value (1)
b)
Signalbus
Sensors (1)
PID (2)
Actuator (3)
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Chapter 16 Component based embedded systems
Inter-component communication
Based on Signal Bus
Signal Bus communication is maintained by Object
Manager
Communication itself is based on signals
One source per signal
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Chapter 16 Component based embedded systems
Types of Interfaces
User Interface
Realtime
Communication Link
Mass storage Interface
(1)
(2)
(3) (4)
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Chapter 16 Component based embedded systems
Prerequisites for effective development
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Chapter 16 Component based embedded systems
Framework
Component Repository
Composition environment
Run-time environment
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Chapter 16 Component based embedded systems
Prerequisites II
Component-based architecture for field devices
Framework, Compile time optimizations, Field-bus architecture,
Repository
Storage and retrieval of components, Storage of non-functional properties, implementation, support and test scripts,
Versioning
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Chapter 16 Component based embedded systems
Prerequisites III
Composition environment
Constraint verification, Component adaptation and code generation, Composition techniques,
Definition of composition rules
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Chapter 16 Component based embedded systems
Prerequisites IV
Run-time environment
Provide efficient implementation model, Address embedded systems constraints, Allow for compilation to optimized firmware thus allowing for no extra run-time environment that RTOS
Allow for hardware and RTOS independent implementation of components
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Chapter 16 Component based embedded systems
Case study summary
Architecture of the field device
Prerequisites for effective development
Framework
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Chapter 16 Component based embedded systems
Presentation summary
Introduction
Component technology in embedded systems
Case study – ABB’s Field Devices
Prerequisites for effective development of based embedded systems
Component-Summary