1. An Introduction to Embedded Software Architecture and Design
Class 1: Introduction to Embedded Software Architecture
December 1, 2014 Jacob Beningo, CSDP

2. Course Overview Introduction to Embedded Software Architecture
Software Architecture using UML
Understanding Embedded Software Architectures
From Architecture to Implementation
Software Architecture of a UAV and Review

3. Session Overview The Software Development Process
What is a Software Architecture?
Why use an Architecture?
Architecture Design Steps

4. Software Development Process
Requirements
Design
Construction
Testing
Maintenance
IEEE Computer Society SWEBOK v3.0

5. Software Development Process
Design
Architectural Structures and Viewpoints
Architectural Styles
Design Patterns
Architecture Design Decisions
Families of Programs and Frameworks
IEEE Computer Society SWEBOK v3.0

6. What is a Software Architecture?
IEEE 1471
Architecture is the fundamental organization of a system embodied in its components, their relationship to each other, and to the environment, and the principles guiding its design and evolution.
High Level Structure
No implementation details!
Language agnostic

7. What is a Software Architecture?
Architecture describes
Fundamental organization and interaction of the system and subsystem components
Describes features that persist throughout the “life” of the product
Should not be easily changed!
Does NOT have design details!

8. What is Software Architecture?
Documenting a Software Architecture
Creating block diagrams
Component interconnects
Subsystem Level blocks
Identifying models
“Design” Patterns

9. What is Software Architecture?
Documenting a Software Architecture is NOT
The nitty gritty details
Function naming ….
Variable definition and naming
Task definition
Classes, methods, interfaces
API’s

10. What is a Software Architecture?
The core pieces of a software architecture
Identifying system components
Understand how components interact with
Other components
Their environment
Organizing the components into a system that is
Understandable
Modular
Maintainable

11. Why an Architecture? What can a software architecture really do?
It can speed up development
It can help to reduce bugs
It can ease software maintenance
Simplify software testing
Improve diagnostics
Save company money
Provide a long robust life for the software

12. Why an Architecture? Why use a software architecture?
Define the elements in the design
Understand relationship of the components
Describe the structure and behavior of the system
Identify engineering decisions
Review and hash out the design before implementation
Identify holes in the requirements and implementation

13. Architecture Design Steps
Step 1 – Identify system components
Drivers
Microcontroller Peripherals
External Sensors
Application
Driving a motor
Filtering sensor data
Configuration
How peripherals and sensors need to be setup

14. Architecture Design Steps
Step 2 – Understand component relationships
Which components interact?
What layer does the component belong in?
Create a component layer architecture
Timer
Digital I/O
PWM
ADC
Sensor Filtering
Motor

15. Architecture Design Steps
Step 3 – Define the Environmental Factors
Hard Real-Time Constraints
Soft Real-Time Constraints
Sensors and hardware interfaces
System Timing
Human interactions
Identify synchronous events
Identify asynchronous events

16. Architecture Design Steps
Step 4 – Create a High Level Architecture
Primary system states
Interrupts
System Tasks
System State Machines
System Events
Concurrent States
Entry/Exit Points

17. Architecture Design Steps
Step 5 – Implement Flowcharts and Sequences
The devil is in the details
Expand the state machines behavior
Identify communication sequences
Simulate the flowchart behavior
Identify high risk areas
Refactor and simplify
Keep it language independent

18. Architecture Design Steps
Step 6 – Review the Architecture
Let the architecture sit for a day or two
Forget and come back to it with fresh eyes
Review with a group of peers
Flush out missing components, complications
Identify potential areas of risk
Verify system requirements
Update and refactor
Always remember to keep it simple!

19. Software Architecture Tips
Use it as a guide
It will change during implementation!
Testing will reveal flaws
Helps wrap the mind around implementation
Always do a group review of the architecture
Keep it as general structure
Keep it language independent
Look for refactoring and simplification

20. Additional Resources Download Course Material for Edraw UML Templates
Updated C Doxygen Templates
Misc Papers and Websites for further reading
From under
- Blog and Articles > Software Techniques > CEC Software Architecture Materials

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