Software modeling for embedded systems: static and dynamic behavior

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• Software modeling for embedded systems static
  and dynamic behavior

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• Important concepts in embedded systems
• --concurrency the system can handle multiple
  active independent or cooperating objects at the
  same time
• --thread of controlmodels sequential execution
  of a set of instructions embedded system may
  have several concurrent threads operating
  simultaneously
• --persistencehow long does a software object
  last?
• Examples
• Temporary variable
• Global variable
• Software module

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table_05_00
Recall UML syntax can vary among
implementations Previously we looked at one
implementation, here we consider examples from
the text
table_05_00
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fig_05_00
UML Use case diagram (graphical)
fig_05_00
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fig_05_01
UML Use case diagram--example
fig_05_01
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fig_05_02
UML Use case diagram (text) note exceptions
fig_05_02
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• UMLstatic modeling

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fig_05_03
UML Class diagram (CRC card) Class
name data Methods (responsibilities and colla
borators)
( collaborators)
fig_05_03
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fig_05_04
UML class relationships inheritance
fig_05_04
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fig_05_05
UML interfacesimilar to inheritance but
different public appearance Hidde
n operation
fig_05_05
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fig_05_06
UML containment of one class within
another Type 1 aggregationstatistical analysis
has a number of algorithm parts
fig_05_06
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fig_05_07
UML containment of one class within
another Type 2 compositionhere the intervals
are meaningless outside the schedule ( local
variables)
fig_05_07
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• UMLdynamic modeling

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fig_05_08
UML interaction diagramcall and return
fig_05_08
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fig_05_09
UML interaction diagramcreate and destroy
fig_05_09
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fig_05_10
UML interaction diagramsend (no response
expected)
fig_05_10
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fig_05_11
UML sequence diagram sequence of actions
carries out a use case
fig_05_11
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fig_05_12
UML sequence diagram--example
fig_05_12
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fig_05_13
UML concurrent behavior. Example fork and
join
fig_05_13
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fig_05_14
UML concurrent behavior. Example branch and
merge
fig_05_14
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fig_05_15
UML activity diagramcaptures all actions and
control flows within a task
fig_05_15
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fig_05_16
UML state machine models--4 types of
events UML state chart is a
directed graph
fig_05_16
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fig_05_18
UML state chart types of transitions
initial state
final state
fig_05_18
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fig_05_19
UML state chart actions and guard conditions If
guard condition is false, transition does not
happen
fig_05_19
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fig_05_20
UML can decompose state into sequential substates
fig_05_20
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fig_05_21
UML can define a history state (e.g., for an
interrupt)system will probably eventually return
to this state
fig_05_21
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fig_05_22
UML can have concurrent substates
fig_05_22
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• UML is a tool for a structured design methodology
• It helps manage the design and development
  process
• We can also look at modifying / refining the
  PROCESS itself

CMM capability maturity model--defines level of
the development process itself 1. Initial ad
hoc 2. Repeatable basic project management
processes in place 3. Defined documented
process integrated into an organization-wide
software process 4. Managed detailed measures
are collected 5. Optimizing--desired level
Continuous process improvement from quantitative
feedback
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• UML is a tool for a structured design methodology
• It helps manage the design and development
  process
• We can also look at modifying / refining the
  PROCESS itself

CMM capability maturity model--defines level of
the development process itself 1. Initial ad
hoc 2. Repeatable basic project management
processes in place 3. Defined documented
process integrated into an organization-wide
software process 4. Managed detailed measures
are collected 5. Optimizing--desired level
Continuous process improvement from quantitative
feedback
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fig_05_23
Another methodology control flow and data flow
diagrams (Note in a processor we usually have a
data path and a control path)
fig_05_23
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fig_05_24
Control and data flow diagrams tasks (with
hierarchy levels)
fig_05_24
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fig_05_25
Control and data flow diagrams Data sources
and sinks
fig_05_25
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fig_05_26
Control and data flow diagrams Data stores
fig_05_26
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fig_05_27
Control and data flow diagrams Example
fig_05_27
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fig_05_28
Control and data flow diagrams Hierarchical
view of an input / output task
fig_05_28