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Engineering Design Process

ECE503Computer Engineering Design


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System Specification

Problem ID

Research

RequirementSpecification

Requirementsmeet needs?

Concept Generation

SystemSpecification

System Integration& Testing

System ProperlyFunctioning

Done


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System Design

Conceptualization

Synthesis

Analysis


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Conceptualization

Develop a rough, early form of solution

An idea or notion that can be a solution

Primitive solutions, no definite form or

character

Lack organization and structure


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Conceptualization

Develop a rough, early form of solution

Made an alarm clock with a 5 time solatreminder

Primitive solutions, no definite form or

character

Lack organization and structure


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Synthesis

Create a well-defined structure for theconcept

Sufficient detail that helps analysis

Preliminary design

Block diagram of the system

Each block will be designed in the detaileddesign


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Analysis

Determine if the synthesized system meets theobjectives

Determine the risks

Develop mathematical model for the blocks

Analyze (simulations or experiments)

Go back to synthesis, refine a solution

Analyze again

Evaluate the alternative solutions

Choose one solution


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System Specification Document

Explain the principle of operation Background information

The Concept

With specification of inputs and outputsThe block diagram

Subsection for each blockFunctional description

of the blocks

How the blocks interact with one another to

make the system work

Description of the

system

Results of mathematical analysis, simulationsand experiments and evaluationsSystem analysis


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DACW5TPR top-downdesign

top-down designersenvision the system and

then build the parts.


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Example :

Develop a functional design for a system that measures and displaysthe speed of a bicycle. Be sure to clearly identify the design levels,functional requirements, and theory of operation for each level.

The system must Measure instantaneous velocities between zero and 75 miles per

hour with an accuracy of 1% of full scale. Display the velocity digitally and include one digit beyond the

decimal point. Operate with bicycle tires that have 19, 24, 26, 27 inch radius.


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Level 0 Architecture The overall goal is to triggered sound during

DACW5TPR

LCDRTC

Push Button

Keypad

Digital Speedometer System Functionality

Buzzer

Timer


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Functional Description

DACW5TPRModule

Real Time Clock (RTC) Keypad Reset button

Input

LCD for display time (hour, minute & second) and date.

Buzzer for time prayer reminder and alarm reminder.

Output

Trigged sound when prayer time reached while displayed time anddate. Alarm reminder trigged sound when time set by user.

Functionality


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Level 1 Architecture

ResetButton

PIC16F87

7

Keypad

Buzzer

Real Time

Clock

LCDUserInterface

PowerSupply

5v dc


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A timer is a specialized type of clock. A timercan be used to control the sequence of anevent or process.


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Real Time ClockModule

clocks and calendars programmable alarms with event recording power supervision including backup battery and system shutdown

management.

Input

Output

Counts in 10ms increments when Vr is low and resets when Vr ishigh.

Functionality

Functional Description


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The counter will only need to count in intervals of 10 ms (100Hz) because the fastest recording of speed will be at75 MPH using a 19 inch tire. This equates to about 22.11 rotations per minute. Therefore 100ths of a second wouldbe sufficient. Refer below.

75 miles / hour * hour / 3600 sec * 63360 inches / mile = 1320 inches/s (fastest)

NOTE: The time the Hall Effect sensor will activate would be shortest with a tire that has the shortestcircumference. This tire would be the 19 inch tire

C = pi*d = 3.14 * 19 = 59.69 inches 1320 inches/sec * rotation/59.96 inches

= 22.11 rotations/s

The size of the bit value passed should be based on the slowest a person could go (longest count time) consideringthe accuracy of our device. Refer below.

1% accuracy of 75 MPH = .01 * 75 = 0.75 MPH (the slowest recordable speed).

75 miles / hour * hour / 3600 sec * 63360 inches / mile = 13.2 inches/s (fastest)

NOTE: The time the Hall Effect sensor will activate would be longest with a tire that has the longest circumference.This tire would be the 27 inch tire.

C = pi*d = 3.14 * 27 = 84.83 inches 13.2 inches/sec * rotation / 84.83 inches

= 0.1556 rotations/s

or (by inversing)

= 6.5 sec / rotation

Therefore, the number of placements the counter needs to hold is 6.5 seconds (using 10 ms increments), which

turns out to be 650 counts. This can be easily obtained with a 10-bit representation (1024 counts).


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Software Developement


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Startprogram


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The system must

Read rtc programme of settingyear,month,day,hour,minutes,seconds.

Store the average, median, and standarddeviation values on disk.


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Main()Module

noneInput

arguments

NoneOutput

arguments

The main function is to call all the program that have been write inthe PIC16F877A.

Description

Software Functional Description


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LCD Initialization SubroutineModule

No of Row Data Size mode Display Type Cursor Mode

Inputarguments

To LCD registerOutput

arguments

To initialize LCD. Hex number send to lcd register to set lcd Mode.4 lcd registers need to be set ( line, data width, blink, cursor)

Description

Software Functional Description


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