page 1, cbse graduate course lecture 3 cbse in embedded system development

, CBSE graduate course

Lecture 3 Lecture 3

CBSE in Embedded System DevelopmentCBSE in Embedded System Development

AgendaAgenda

Embedded and Real-Time Systems

ProCom

Extra-Functional Properties

PRIDE

Lab2


What are Embedded Systems ?What are Embedded Systems ?

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““special purpose computer built special purpose computer built into a larger device to perform a into a larger device to perform a

specific functionality by specific functionality by combination of hardware and combination of hardware and

software”software”

April 21, 2023Component-based real-time systems

Interaction with the environmentInteraction with the environment

A sensor transforms physical data (temperature, pressure) to digital format

Examples: thermometer, microphone, video camera

An actuator works the other way round - transforming digital data to physical format.

Example: motors, pumps, machines…

An embedded system interacts with the environment via An embedded system interacts with the environment via sensorssensors and and actuatorsactuators

RTRTsoftwaresoftwaresystemsystem

SensorSensor

ActuatorActuatorEnvironmentEnvironment

Does someone know an example of an Does someone know an example of an

embedded system that you can find in a embedded system that you can find in a

car?car?


An airbagAn airbag


Example:Example:

An air bag must not be inflated too late, nor too early!An air bag must not be inflated too late, nor too early!

CollisionCollision

Too lateToo late

timetime

Too earlyToo early

Correct results at the right timeCorrect results at the right time

What is a real-time system?What is a real-time system?

““A real-time system is a system that A real-time system is a system that reacts upon outside events reacts upon outside events and performs a function based on these and and performs a function based on these and and gives a response and gives a response within a certain timewithin a certain time. Correctness of the function does not only . Correctness of the function does not only depend on correctness of the result, but also the depend on correctness of the result, but also the timeliness timeliness of it”.of it”.

April 21, 2023

Event driven real-time systems

External events determines when a program is to be executed

Often through interrupts

Example: telephone switches, ”video-on-demand”, transaction systems…

Time driven real-time systems

The system handles external events at predefined points in time

Most often cyclic systems repeats a certain scenario

Example: ABS, control systems, manufacturing systems…

Event driven vs. time driven systemsEvent driven vs. time driven systems

Predictable vs. fastPredictable vs. fast

A robot arm with A robot arm with good timing catches good timing catches the passing boll.the passing boll.

April 21, 2023Ivica Crnkovic (c) : Component-based real-time systems

Too fast robot arm Too fast robot arm misses the passing misses the passing boll!boll!

Predictable vs. fastPredictable vs. fast

What do you need to think about when What do you need to think about when

developing ES?developing ES?

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Heterogeneous Development ConcernsHeterogeneous Development Concerns

Predictable

react in well-specified ways and be highly dependable

Real-time demands

react correctly to events in a given interval in time

Resource limitations

memory

bandwidth

power

…

1313

Current Trend Current Trend

Today, the software part increases Additional functionality HW functionality replaced by

SW functionality

““special purpose computer built into a larger device to special purpose computer built into a larger device to perform a specific functionality by combination of perform a specific functionality by combination of

hardware and software”hardware and software”

““special purpose computer built into a larger device to special purpose computer built into a larger device to perform a specific functionality by perform a specific functionality by combination of combination of

hardware and softwarehardware and software””

1414

Problems in current development methodsProblems in current development methods

Traditional development method does not scale anymore (1 functionality/subsystem on 1 ECU)

Software complexity

Distribution

Shared resources

Need solutions to:

Manage software complexity

Improve reusability

Address some fundamental development concerns:Timing demands

Resource limitations

Predictability

1515

CBSECBSE

––

The future of ES The future of ES

development?development?

General RequirementsGeneral Requirements

Cover the whole development process

From early design up to deployment and synthesis

Centered around a unified notion of components

Collection of requirements, documentation, source code, analysis models, test results, etc.

Enable the integration of various analysis techniques

Manage and store the required/produced artefacts in a systematic way

1818

Coexistence of Different Abstraction LevelsCoexistence of Different Abstraction Levels

Example of development process

1919

RequirementsRequirementsSpecificationSpecification

Component Component repositoryrepository

Reuse of an Reuse of an already existing already existing solutionsolution

Fully implemented Component

(architecture model+source code

+analysis model)

Partially implemented component

Sketch of component

Component-Based Component-Based DesignDesign

DeploymentDeployment

Different Concerns at Different Granularity Different Concerns at Different Granularity LevelsLevels

2010-03-08Pau

2020

Resource limitationsResource limitations Real-time demandsReal-time demands PredictabilityPredictability DistributionDistribution

ES specific requirementsES specific requirements

Managing complexityManaging complexity Different abstraction levelsDifferent abstraction levels Different concerns at different levelsDifferent concerns at different levels Integration of various analysis techniquesIntegration of various analysis techniques

Component-based approach requirementsComponent-based approach requirements

Response-timeResponse-time CPUCPU Memory UsageMemory Usage ReliabilityReliability AccuracyAccuracy

Extra-Functional PropertiesExtra-Functional Properties

2010-03-08

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Specifies component Specifies component semanticssemantics

Composition rulesComposition rules

Component ModelComponent Model

ProCom ProCom –– Key aspects (1) Key aspects (1)

Rich design-time concepts

A collection of development artefacts(source code, models of timing and resources, analysis results,

documentation, etc.)

Reuse all this information.

Components of different maturity should be allowed to co-exist.

2323

ProCom ProCom –– Key aspects(2) Key aspects(2)

Components abstracted from physical deployment

Different concerns depending on granularity:

Distribution, communication, analysis, etc.

2424

Architectural Architectural model (CBD)model (CBD)

Platform modelPlatform modelmappingmapping

ProCom ProCom a Two-Layered Component a Two-Layered Component

ModelModel

2010-03-08

2525

SystemSystem

C1C1C1C1 C2C2C2C2 C3C3C3C3

ProSys (upper layer)ProSys (upper layer)

"Function block" components"Function block" components Passive, non-distributedPassive, non-distributed Explicit transfer of data and controlExplicit transfer of data and control HierarchicalHierarchical

ProSave (lower layer)ProSave (lower layer)

A subsystem can internally be modelled by ProSave.A subsystem can internally be modelled by ProSave.

Connection between the layersConnection between the layers

ProSys – the upper layerProSys – the upper layer

Components (subsystems):

Active, possibly distributed.

Interact through message ports.

2626

Subsystem ASubsystem A

Subsystem BSubsystem B

Subsystem CSubsystem C

ProSys –communicationProSys –communication

Communication

Asynchronous messages

Explicit message channelsDesign entity for data shared between subsystems

Not a physical message channel like a bus !

steeringsteeringangleangle

speedspeed

ProSave – the lower levelProSave – the lower level

Passive components(similar to task or function block)

Interact through input- and output ports.

Data ports

Trigger port

Component semantics:

Initially passive, receivinginput data.

When triggered, read inputdata and turn active.

Write output once.

Return to the passive state.

Component Component AA

ProSave ProSave –– the lower level the lower level

More complex components can have: Multiple output groups:

Output can be produced at different points in time.

Each group written once per activation.

Multiple input groups (services):Services can share state.

Individual control flows

Component Component AAComponent Component AA

2010-03-08

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Pau

Component CComponent C


Separated data- and control flow

Component AComponent A Component BComponent B

• Hierarchical nestingHierarchical nesting• Primitive components (implemented in C)Primitive components (implemented in C)• Composite componentsComposite components


Connectors for more elaborate control:

3131

– Data forkData fork– Data orData or

– Control forkControl fork– Control joinControl join– Control selectionControl selection– Control orControl or

Modelling a ProSys subsystemModelling a ProSys subsystem

in ProSavein ProSave

Message ports trigger and data

Clocks and events

3232

C1C1 C2C2

C3C3

10 Hz10 Hz

Electronic Stability Control in ProSysElectronic Stability Control in ProSys

3333

Stability Control System in ProSave Primitive Stability Control System in ProSave Primitive

SubsytemsSubsytems

2010-03-08

3434

Pau

ProCom – SummaryProCom – Summary

A component model for “distributed control-intensive embedded systems”

Rich design-time component notion including models, properties, realisation, analysis results, etc.

Two layers for addressing the different paradigm existing at different abstraction level:

ProSys: Active subsystems, message passing.

ProSave: Passive components, trigger/data flow.

3535

3737

ProComProCom

Component-Development Approach

Extra-functional Extra-functional properties ???properties ???Analysis ???Analysis ???

A Huge List of PropertiesA Huge List of Properties

3838

Execution timeExecution timePrioritiesPrioritiesDeadlineDeadline

Schedule policySchedule policyEnd-to-end deadlineEnd-to-end deadline

Response timeResponse timeComputation timeComputation time

WCET/BCETWCET/BCET

Static memory usageStatic memory usageDynamic memory usage Dynamic memory usage

CPU usageCPU usagePower consumptionPower consumptionMemory footprintMemory footprint

Disk accessDisk accessNetwork accessNetwork access

SafetySafetyReliabilityReliabilityAvailabilityAvailability

RecoverabilityRecoverabilityMaintainabilityMaintainabilityAccessibilityAccessibility

Nb of reuseNb of reuse

ThroughputThroughput

Confidentiality Confidentiality

Nb of testsNb of tests

CostCost

Value rangeValue range

Compliance to standardCompliance to standard

PrecisionPrecision

ExtensibilityExtensibility

ConfidentialityConfidentiality

IntegrityIntegrity

SecuritySecurity

EvolvabilityEvolvability

CredibilityCredibility

AccuracyAccuracy

LoCLoC

......

Characteristics of Extra-Functional Characteristics of Extra-Functional

PropertiesProperties

Different representations

numbers, intervals, formula, models, image, ...

Different techniques to obtain the values

model checking, measurement, calculation, expert estimate, ....

Relation to different entities

system, component, interfaces, links, ...

Validity conditions: context

hardware, specific library, scheduling policy, usage Profile, other properties, ...

3939

ExampleExample

4040

Static Static Memory UsageMemory UsageStatic Static Memory UsageMemory Usage

value: 10, kBvalue: 10, kB

version: 1version: 1

timestamp: 080120#17:44timestamp: 080120#17:44

source: estimationsource: estimation








source: measurementsource: measurement

platform: Xplatform: X




source: measurementsource: measurement


WCETWCETWCETWCET

value: 25, clock cyclevalue: 25, clock cycle



source: analysissource: analysis





source: analysissource: analysis










PRIDEPRIDE

The ProCom

Integrated Development Environment

Main IdeaMain Idea

Emphasis on component development & component reuse

Seamless integration of analysis techniques

4343

Components: a central conceptComponents: a central concept

Components are the main units of development

They follow the rich-desgin component concepts

“a component is the collection of all the artefacts produced or required during the development process”

Concretely, based on a predefined file structure

Source code folder,

Models folder,

Documentation folder,

Metadata file

4444

The various facets of a componentThe various facets of a component

Component type

Defines all the fixed parts of the component

Characterised by:a universally unique ID,

a name (possibly non-unique)

a architectural description (ports, services, etc.)

a functionality

Component instances:

Refer to the corresponding component type

Used during the design and realisation of composite components

Can have additional information, specific to that instanceEx: worst case execution time

4545

Overview of the Overview of the

ArchitectureArchitecture

4646

PRIDEPRIDE

Component Component ExplorerExplorer

ComponentComponentEditorsEditors

SynthesisSynthesis

Analysis ToolsAnalysis Tools

Attribute DefinitionsAttribute Definitions

Fault-Fault-PropagationPropagation

ParametrParametric WCETic WCET

EFP EFP AssuranceAssurance

REMES REMES SimulatorSimulator

REMES REMES EditorEditor

creates creates and and addsadds

Analysis Analysis ExpertExpert

usesuses

AnalystAnalyst

ComponentComponentRepositoryRepository

Core ConceptsCore Concepts

CBSECBSEProComProCom

Rich Rich ComponentsComponents

System System DeveloperDeveloper

import/import/exportexport

synthetisesynthetise

Binary Binary FilesFiles

Support Support for EFPsfor EFPs

Runtime Runtime EfficiencyEfficiency

......

......

DemoDemo


Introduction to Lab2Introduction to Lab2



ObjectivesObjectives Apply component based software engineering principles to

embedded system development

Model an embedded system using a component based model

Reuse components between systems

Calculate its non functional properties

Learn about composition and interaction semantics

Uses a dedicated tool suite.

Expected OutputExpected Output

Same system as for Lab1

Archive files only (no folder) named ”Lab2X_Y.zip” where X=your name (and Y=name of your teammate if you work in pair).1 report explaining your design choices and calculation results

The Project folder for your system

Individual work (or in pair)

But nothing else!

Both have to submit the archive file

Do not copy solutions from others !

, April 21, 2023Advanced CBSE

DeadlineDeadline

Tuesday 08 February 2011 23:59 (FIRM Deadline!)

If you submit your work late, you fail one submission opportunity => only one chance to pass the lab before Exam1!

Remember.

Lab2 must also be approved to before Exam 1


The assignmentThe assignment

In 3 parts

Modelling an industrial Baking Conveyor System using ProCom and PRIDE

Practice reuse of components in adapting the system

Calculate extra-functional properties on simple cases


The Industrial Baking Conveyor System The Industrial Baking Conveyor System


Main parts:Main parts:

Temperature Sensor

Humidity Sensor

Heating Unit

Orchestrator

Oven

Conveyor Belt

Usage ScenarioUsage Scenario


Orchestrator

OvenConveyor Belt

Oven monitors the temperature and humidity sensorOven monitors the temperature and humidity sensormeasurements and determines 1. if the heat should measurements and determines 1. if the heat should be increased and 2. if the cookies are cooked be increased and 2. if the cookies are cooked correctlycorrectly

Carries the cookies Carries the cookies from point A to point B from point A to point B in passing by the ovenin passing by the oven

Ensure that the conveyor belt Ensure that the conveyor belt and the oven are working and the oven are working togethertogether

Part 1 - What you need to do?Part 1 - What you need to do?

To model this system with ProCom and PRIDE

Tip 1 Start by understanding last year assignment (

http://www.idt.mdh.se/kurser/cd5490/2010/Assignment%202/index.htm )

Use pen and paper before PRIDE

Once you are sure of your solution. Model it in PRIDE

Tip 2:While designing components, think about reuse

What would make that component more reusable?

What would prevent to reuse that components in different systems


Part 2 - ReusePart 2 - Reuse You want to develop software for a second type of

industrial baking conveyor system


Conveyor Belt

Rotating Table

OvenOven

Waste

OkOk

Part 2 - What you need to do?Part 2 - What you need to do?

To model this second system with ProCom and PRIDE

Tip Think carefully on the first system with reuse in mind

What are the impacts of this change in the model you design for the first system?

What are the components that you can reuse?

What need to be added or modified? And Why?


Part 3 – Calculate Extra-Functional Part 3 – Calculate Extra-Functional

PropertiesProperties

First on a simple example, you will need to

Calculate static memory usage of whole system, based on static memory usage of all components used in system

Calculate WCET of the system, based on all possible execution paths

Then on the oven element of your system, you will need to

Calculate static memory usage of element, based on static memory usage of all components used in system

Calculate its WCET, based on all possible execution paths


Static Memory Usage and WCETStatic Memory Usage and WCET

Static memory usage (without considering the glue code)

10 (A) + 8 (B) + 6 ( C) + 10 (D) = 34

Execution paths

(I) A → B → D , (II) A → C → D

WCET

Path (I) = 5 + 15 + 15 = 35

Path (II) = 5 + 20 + 15 = 40 = WCET


Questions ?!?Questions ?!?


Questions ?!!?Questions ?!!?

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