ECE/7th Sem/ERTS/EC8791/Unit-1/Design methodologies

1. RMK COLLEGE OF ENGINEERING AND
TECHNOLOGY
DEPARTMENT OF ELECTRONICS AND
COMMUNICATION ENGINEERING
EC8791
EMBEDDED AND REAL TIME SYSTEMS
S. Rajalakshmi
AP/ECE

2. DESIGN METHODOLOGIES
Why Design Methodologies?
When several people work together on a COMPLEX PROJECT, they need to
agree on who will do things and how they will get done.
explicit about process is important when people work together..

3. Design flow
• Design flow: sequence of steps to be followed in a
design.
• 5 Models :
• Waterfall model
• Spiral model
• Successive refinement
• Hierarchical design flows
• Concurrent Engineering

4. 1. Waterfall model
Introduced by Royce , the first model proposed for the software
development process.
requirements
architecture
coding
testing
maintenance
• Requirements: determine basic characteristics.
• Architecture: decompose into basic modules.
• Coding: implement and integrate.
• Testing: exercise and uncover bugs.
• Maintenance: Periodical check to upgrade.

5. Waterfall model critique
• Multiple iterations
• Assumptions.
• an unrealistic design process
So, an alternative model of software development called the
spiral model .

6. 2.Spiral model
requirements
test
design
system feasibility
specification
prototype initial
system
enhanced system

7. Spiral model critique
• Successive refinement of system.
– Start with mock-ups, move through simple systems to
complex full-scale systems.
• Working through stages may take too much time.

8. Successive refinement model
specify
architect
design
build
test
initial system refined system
The system is built several times. A first system is used as a rough prototype,
and successive models of the system are further refined.
specify
architect
design
build
test

9. Hardware/software design flow
requirements
and
specification
architecture
hardware design
software design
integration
testing
Front end
Back end
Middle end

10. Hierarchical design flow
• Embedded systems must be designed across multiple
levels of abstraction:
– system architecture;
– hardware and software components.
– Eg: GPS interface with satellite

11. A hierarchical design flow for an
embedded system.