EECE 276 Embedded Systems - School of...
Transcript of EECE 276 Embedded Systems - School of...
EECE 276 – Embedded Systems 2
Overall document structureIntroduction What?
Purpose Why?Scope Scope of systemDefinitions, Acronyms, Abbreviations ListsReferences Standards, etc.Overview
Overall Description Big pictureProduct Perspective InterfacesProduct Functions What It doesUser Characteristics User categoriesConstraints LimitationsAssumptions and Dependencies
Specific Requirements External interfaces, main classes,performance, timing
Appendices
EECE 276 – Embedded Systems 5
Traffic Light Control System
From textbook (Laplante ’04)
Overall Description
EECE 276 – Embedded Systems 6
Traffic Light Control SystemProduct Perspective
System InterfacesUser interfacesHardware interfacesSoftware interfacesCommunication interfacesMemory constraintsOperations
Product functionsUser characteristics
PedestriansMotor vehiclesTraffic Regulatory PersonnelSystem Administrators
ConstraintsRegulatory policyNetwork protocols…
AssumptionsSI unitsCommercial RTOS…
EECE 276 – Embedded Systems 7
Traffic Light Control System
From textbook (Laplante ’04)
Hardware Interfaces
EECE 276 – Embedded Systems 8
Traffic Light Control System
From textbook (Laplante ’04)
Specific requirements:
Top-level use-case diagram
EECE 276 – Embedded Systems 9
Traffic Light Control System
From textbook (Laplante ’04)
Specific requirements:
Preliminary class diagram
EECE 276 – Embedded Systems 10
Traffic Light Control System
From textbook (Laplante ’04)
Specific requirements:
Sample class description
EECE 276 – Embedded Systems 11
Traffic Light Control System
From textbook (Laplante ’04)
Specific requirements:
Statechart for controller sequence
EECE 276 – Embedded Systems 12
Traffic Light Control System
From textbook (Laplante ’04)
Specific requirements:
Timing requirements
EECE 276 – Embedded Systems 13
Summary
Requirement analysis is critical for good system design» Errors made here are very hard to rectify later
Structured techniques are available» Small-scale: FSM, Statechart, Petri-Net» Large-scale: Functional, OOAD
Requirement documents capture essential information» Format and content are often regulated by
government agencies (FAA, DoD, NASA)