109-Embedded21Embedded Systems Details209-Embedded2Object Model: Four mainsystem objects or classes●Controller object■might be made up of several controllers■is the brains of the system.■Takes input from the sensors and gives instructions to theactuators.●Sensor object■environmental objects that gives information to controller.■Can be passive (thermometer) or active (button).309-Embedded2Object Model: Four mainsystem objects (continued)●Actuator object■Environmental objects that are controlled by the controller.■Can be turned on or influenced by controller.■Examples: User indicator lights, motors, burners.●User Interface object■A display for the user.■Can be made up of both sensors and actuators.■Example: machine control panel409-Embedded2Step One: Develop a high-levelobject modelEmbeddedSystemSensorControllerActuatorUser-InterfaceClassAssociationAggregationInheritanceZero or moreOperation()Attribute()Class NameButtonPedal****509-Embedded2Review of Dynamic Model●A dynamic model is a type of state machine.●System can only be in one state at a time.●Arrows: Transitions■from one state to another happen■when events happen.●Events are labeled on the transitions.●Guards are conditions that keep a transition fromhappening, such as [is in neutral or park ]609-Embedded2Step Two: Develop a system-level dynamic modelIdle or off stateRunning state‘On’ button pushed [in neutral or park]‘Off’ button pushedTransitionState[ condition ] Guard2709-Embedded2Example: Automotive DoorControl●The system controls the windows and door lockingfunctions.●All doors have window roll up and down controls.●Driver’s door has window lock feature.●Driver and front passenger have door lock and unlocktoggle.●Fob unit for locking and unlocking doors, with drivernotification (horn honk and lights flash.)●Three concurrent systems identified.809-Embedded2909-Embedded21009-Embedded21109-Embedded21209-Embedded231309-Embedded21409-Embedded21509-Embedded2Summary of developmentprocess●The object model shows the real world objects grouped inclasses with attributes and operations and associations.●The dynamic model shows the control aspects withsuperstates refined into substates.09-Embedded216Embedded Systems DesignMore Detail on Process1709-Embedded2Review of Embedded Systems●Software controller that is interacting with itshardware environment through sensors andactuators.●Concurrency and real time issues.●Safety critical nature of many of these systems.●Increased demand for these systems to bedesigned well.1809-Embedded2High level design: Initial thoughtsfor embedded systems.●Assume there is a hardware environment.●Assume that somehow the needed signals arecoming from the environment (sensors.)●Assume the needed hardware is there to respondto your signals (actuators.)41909-Embedded2Object Model●In UML the object model is the starting placefor the modeling process.●The object model will include objects andtheir relationships.●The Object Model will be the static, structuralaspect of the system.Classattributeoperation2009-Embedded2Identify Real World Objects●Read over the problem description and find thenouns in the text.●These nouns are candidates for objects in yourobject model.●Discard unnecessary and incorrect classes.●Object classes will include the controller (softwareunit that will be built), sensors, and actuators.2109-Embedded2Data Dictionary: needs to bewritten●A written paragraph describing each modelingentity.●Needed so that names are non-ambiguous.2209-Embedded2Class: Sensor●Because of the common properties of allsensors, this can be a class of objects, calleda superclass.●Generalization - this superclass can begeneralized into subclasses.●Inheritance - each subclass will inherit theproperties or features from the superclass.●Examples: user interface (buttons etc),thermometers, hardware sensors.2309-Embedded2Class: Actuator●Similarly the actuators will probably become asuperclass.●Generalization - The various actuators can begeneralized into subclasses.●Inheritance - each actuator subclass will inheritproperties or features from the superclass.●Examples: LEDs, motor controls, etc.2409-Embedded2The Controller●At an abstract level, this would be only one objectin most embedded systems.●This object would be refined at lower levels of themodeling process into subsystems or sub-objects.●Aggregation could be used to show the parts ofthe controller.52509-Embedded2Model itself●Graphically a class is shown as a box with thename on top.●Attributes (middle third) and operations (bottomthird) added eventually.●Attributes and operations are not needed for high-level object model.Classattributeoperation2609-Embedded2 Find the Associations●Interaction between objects must be shown byassociations or lines draw with labels.■ex: line between user button and associated LED.●Many times these associations will be a physicalconnection between objects in an embeddedsystem.●Multiplicity must be shown eventually.2709-Embedded2ExampleControllerActuatorsSensorsWater levelUser buttonsMotorLEDreadsturned on by**2809-Embedded2Conclusion about Object Model:●Not very complex at first.●More details will come as designer proceedsfrom abstraction to more and moreconcreteness.■controller will be divided into more objects■attributes and operations are identified andincluded.●Starting place for OO Modeling. Sets thestage.2909-Embedded2Next step: Dynamic Model●The dynamic model shows the control aspect ofthe system.●Because embedded systems are mainlycontrollers, the dynamic model is the ‘key’ modelfor embedded systems.●This model can show the timing aspects.●Shows sequence of operations in response toexternal stimuli.3009-Embedded2Getting started on a DynamicModel●Helpful to make a scenario:■sequence of events that happens in one execution of asystem.■Example: insert coins, make selection, pop dispensed.●Interface (high-level prototyping)■a rough draft of user interface will help thinking aboutthe events in an embedded system.63109-Embedded2Interface (type of rapidprototyping)0678843215clearentercancelreceiptscash slotATM interface from Figure 8.17 by Rumbaugh3209-Embedded2continue getting started….●Next make an event trace.■each object is a vertical line.■events as horizontal arrow.■time goes from top to bottom.●Use previously discussed ‘creation