1. Introduction to Structure Design
Anh Nguyen
February 10, 1998

2. Structured Design Motivation Goal
traditional flowcharts are not sufficient
convoluted and vague verbiage documents
bridge between problem specifications and implementation
Goal
to produce maintainable, reliable, and adaptable systems

3. Structured Design Steps to structured design
To reduce the cost of the system in terms of time, money, person-power.
Steps to structured design
understanding the problem and requirements that need to be satisfied
break up the system into smaller, manageable units
apply modeling tool to capture your requirements into a systems design that involves hw and sw

4. Structured Design
Provide a set of criteria for evaluating the quality of your design

5. Structured Design Methods
Structure charts, process specifications, data flow diagrams, etc.
Example of data (control) flow diagram (DFD)
DFD elements
process bubble
data flows and controls
data stores
source/sink

6. Structured Design Methods

7. Structured Design Example
Specifications
Serial task that receives data, transmits data, has flow control
Receive process can receive one character or a block of characters
Transmit process can receive one character or block of characters
Flow control that flows off when receive buffer reaches 70 bytes of its 75 byte buffer by sending a FLOW OFF character (0x13)

8. Structured Design Example
Flow control that flows on when there is at least room for 25 bytes in its receive buffer by sending a FLOW ON character (0x11)
Frequency task that measures the frequency of an input square wave signal and outputs serially the frequency measurement.

9. Structured Design Example

10. Structured Design Example

11. Reference
“The Practical Guide to Structured Systems Design”, Meilir Page-Jones, 2nd Edition, 1988.