A202SE Microcomputer System Coursework

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AUSTONINSTITUTE OF MANAGEMENT CEYLON

Faculty of Engineering

Advanced Diploma in Electrical and Electronics

Engineering

A202SE Micro Computer System

Coursework

Student Name: M. Badurdeen Shakeal

Student ID: T1-11-EEE-L2-86

Supervisor: Mr. Roshan Weerasuriya

Submission Date: 2012.05.28


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PROJECT/ASSGNMENT SUBMISSION ACKNOWLEDGEMENT SLIP

Name of Student: M.BADURDEEN SHAKEAL Student No: 260211/76 T1-11-EEE-L2-86

Home Address: No.2/154, Sejiah Region, Panavitiya, Deekirikewa, 60123, Sri Lanka

Date of Submission: 2012 may 28th Name of Tutor: Mr. Roshan Weerasuriya

Program/ Module: A202SE (Microcomputer Systems)

Received By: _________________________ Date: ___________________________________

Individual Projects (30%)

Coursework1 :Design based C/C++Interfacing Assignment

Marks

Learning Outcome Weightage

1stmarker

2nd

marker/moderat

or

Finalmark

Design and implement software programsfor microprocessors using C/C++specification and design flow.2. Use interfacing methods to enablemicroprocessors to communicate with anexternal hardware system.3. Use modern Integrated DevelopmentEnvironments to support the design flow.

Q1:

Functional operation of an ALU

Design for Logic Extender (LE) Unit

Design for Arithmetic Extender (AE)unit

Design for Carry Extender (CE) Unit

Resultant ALU system

Discussion

Q2:

Principles of a DC motor, itsapplications and control techniques

Interfacing techniques/ designcalculations

Flow chart for motor controlprogram

C/C++ Programmming

Simulation with IDE

Analysis/ Discussion on results

Conclusion

40%

4%11%9%7%5%4%

50%

6%7%6%

10%10%7%4%

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Quality and structure of the report 10%

Total Marks 100%

1st markers comment

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

2nd markers/ moderator comment

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

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Table of Contents

1. Abstract. 02

2. Introduction.. 03

3. Literature Review

3.1. Functional operation of an ALU... 03

3.2. Principle of operation of DC motor and its applications... 04

3.3. Principle of DC motor control... 07

3.4. PIC microcontrollers and development system. 10

4. Design Criteria

4.1. Design calculation for major components of ALU system

4.1.1. Design for logic extender (LE)...... 12

4.1.2. Design for arithmetic extender (AE). 14

4.1.3. Design for carry extender (CE)..15

4.1.4. Resultant ALU System.. 16

4.2. Necessary interfacing techniques for DC motor control...

11

4.3. Necessary design calculation for DC motor control..

12

5. Software implementation

5.1. Flow chart for DC motor control program.....

17

5.2. C/C++ program implementation

18

5.3. Simulation with integrated development environment (IDE)...

19

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6. Critical analysis

6.1. Investigation of different inputs criteria

22

6.2. Discussions and comparisons of results

23

7. Conclusions....24

8. Reference... 25

9. Turn it in Report ... 26

1. Abstract

The motivation behind this course work is designing a four bit ALU which can successfully tackle

logical and arithmetic operations of this module coursework is understand the functional

operation of an Arithmetic Logic Unit (ALU) and DC motor control system using Peripheral

interface controller (PIC) microcontroller.

This micro computer system module coursework has two main questions. First part of this

coursework is designing and calculation of a 4 bit ALU. This Arithmetic Logic Unit was

controlled by three functions. Those are logic extender, arithmetic extender and carry extender. Its

inputs are modes select M and operations select S1 and S0. The mode input is selects between

logic and arithmetic operations. Using the ripple carry full adders as building blocks together with

logic extender unit, here manipulate all logical operations and arithmetic extender unit to

manipulate all arithmetic operations and carry extender unit to modify the carry in signal C 0.

The second main part is designing and implement of a DC motor system. Its controlled by PIC

(peripheral interface controller) microcontroller. PIC16F877A microcontroller and simple motor

driving techniques are used control the DC motor. Microcontroller has been programmed by using

CCS Compiler software and simulated the whole circuit system by using proteus (ISIS

Professional) software. The C programming language has been used here for programming the

microcontroller. Two main input switches are used to control the motor. One switch is used for

rotate the motor clockwise and stop the motor. The other switch is used for rotate the motor anti-

clockwise and also stop the motor.

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2. Introduction

The main object of this microcomputer system coursework has divided two main areas. The initial

object is design a 4bit ALU (Arithmetic Logic Extender) consist of logic extender, arithmetic

extender and carry extender. Also it should have capable of performing both arithmetic and

logical function in a given applications.

The other object is program a microcontroller using C language and

simulates the microcontroller by a simulation software call proteus

and control the motor. The motor is solely based on the idea of

controlling the motor which uses PIC microcontroller technology to

rotate the motor both clock and anti-clockwise and stop, start the

motor. The C language programming is used here for achieve the

objective.

The ALU used here has only a 4 bit capacity. Therefore in can

process maximum for 4 bit operation at a time. According to this

reason these type of ALU is suitable for small operations only. Ill the PIC microcontroller has

ability to perform thousands of operations and process. But the DC motor has only ability itself to

start the motor, stop the motor, increasing and decreasing the speed and changing the rotating

direction. So the PIC is limited to these features only.

The ALU can be controlled by following three inputs.

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M is mode select, S0 and S1 are operation selects

Full adder and ripple carry adder which is need to design the ALU

The figure 2.1 shows the state diagram.

Here Inputs are Xi and Yi

Carry input is Ci

Carry output is C0

Figure 2.1

Literature Review

3.1 Functional operations of an ALU

The ALU (Arithmetic Logic Unit) is a most important part of a microprocessor. The ALU is

operating based on arithmetic and logical operations such as arithmetically adding, subtraction

and logically OR, AND, XOR, NOR, XNOR, and NOT which the microprocessor

comes across. Also it has capability of performing multiplication and division related problem.

ALU is a combinational circuit and its output depends on only the current input. It doesnt care

about previous input. The ALU is process numerical value in the same format as digital circuit

functions. Because now a days computers are twos complement (binary) representations.

Ripple carry full adder has been used here as a building block for ALU designing. The logic

extender (LE) perform the all the logical function and arithmetic extender (AE) compute all the

arithmetic function as well as carry extender control full adders carry values. Each combinational

circuit is designed separately.

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3.2 Principle of operation of DC motor and its applications

DC motor is an electrical machine which is ability of converting direct current electrical power in

to mechanical power. It has a capability of controlling the speed of rotor more accuracy. Inside of

DC motor has a permanent magnet. It can control electrical power to mechanical power using an

interaction which is created by two sides of magnetic fields. One of these is created by permanentmagnet and other field is created by electrical current is within the inside winding.

The direct current (DC) motor is one of the first machines devised to convert electrical power into

mechanical power. Permanent magnet (PM) direct current converts electrical energy into

mechanical energy through the interaction of two magnetic fields. One field is produced by a

permanent magnet assembly the other field is produced by an electrical current flowing in the

motor windings. These two fields result in a torque which tends to rotate the rotor. As the rotor

turns, the current in the windings is commutated to produce a continuous torque output. The

stationary electromagnetic field of the motor can also be wire-wound like the armature (called a

wound-field motor) or can be made up of permanent magnets (called a permanent magnet motor).

In either style (wound-field or permanent magnet) the commentator. An act as half of a

mechanical switch and rotates with the armature as it turns. The commutator is composed of

conductive segments (called bars), usually made of copper, which represent the termination of

individual coils of wire distributed around the armature. The second half of the mechanical switch

is completed by the brushes. These brushes typically remain stationary with the motor's housing

but ride (or brush) on the rotating commutator. As electrical energy is passed through the brushes

and consequently through the armature a torsional force is generated as a reaction between the

motor's field and the armature causing the motor's armature to turn. As the armature turns, the

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brushes switch to adjacent bars on the commutator. This switching action transfers the electrical

energy to an adjacent winding on the armature which in turn perpetuates the torsional motion of

the armature.

Permanent magnet (PM) motors are probably the most commonly used DC motors, but there are

also some other type of DC motors (types which use coils to make the permanent magnetic field

also) .DC motors operate from a direct current power source. Movement of the magnetic field isachieved by switching current between coils within the motor. This action is called

"commutation". Very many DC motors (brush-type) have built-in commutation, meaning that as

the motor rotates, mechanical brushes automatically commutate coils on the rotor. You can use

dc-brush motors in a variety of applications. A simple, permanent-magnet dc motor is an essential

element in a variety of products, such as toys, servo mechanisms, valve actuators, robots, and

automotive electronics.

There are several typical advantages of a PM motor. When compared to AC or wound field DC

motors, PM motors are usually physically smaller in overall size and lighter for a given power

rating. Furthermore, since the motor's field, created by the permanent magnet, is constant, the

relationship between torque and speed is very linear. A PM motor can provide relatively high

torque at low speeds and PM field provides some inherent self-braking when power to the motor

is shutoff. There are several disadvantages through, those being mostly being high current during

a stall condition and during instantaneous reversal. Those can damage some motors or be

problematic to control circuitry. Furthermore, some magnet materials can be damaged when

subjected to excessive heat and some loose field strength if the motor is disassembled.

High-volume everyday items, such as hand drills and kitchen appliances, use a dc servomotor

known as a universal motor. Those universal motors are series-wound DC motors, where the

stationary and rotating coils are wires in series. Those motors can work well on both AC and DC

power. One of the drawbacks/precautions about series-wound DC motors is that if they are

unloaded, the only thing limiting their speed is the wind age and friction losses. Some can literally

tear themselves apart if run unloaded.

A brushless motor operates much in the same way as a traditional brush motor. However, as the

name implies there are no brushes (and no commutator). The mechanical switching function,

implemented by the brush and commutator combination in a brush-type motor, is replaced by

electronic switching in a brushless motor. In a typical brushless motor the electromagnetic field,created by permanent magnets, is the rotating member of the motor and is called a rotor. The

rotating magnetic field is generated with a number of electromagnets commutatated with

electronics switches (typically transistors or FETs) in a right order at right speed. In a brushless

motor, the trick becomes to know when to switch the electrical energy in the windings to

perpetuate the rotating motion. This is typically accomplished in a brushless-type motor by some

feedback means designed to provide an indication of the position of the magnet poles on the rotor

relative to the windings.

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A Hall Effect device (HED) is a commonly used means for providing this positional feedback. In

some applications brushless motors are commutated without sensors or with the use of an encoder

for positional feedback. A brushless motor is often used when high reliability, long life and high

speeds are required. The bearings in a brushless motor usually become the only parts to wear out.

In applications where high speeds are required (usually above 30,000 RPM) a brushless motor is

considered a better choice (because as motor speed increases so does the wear of the brushes on

traditional motors).

A brushless motor's commutation control can easily be separated and integrated into other

required electronics, thereby improving the effective power-to-weight and/or power-to-volume

ratio. A brushless motor package (motor and commutation controller) will usually cost more than

a brush-type, yet the cost can often be made up in other advantages. For example, in applications

where sophisticated control of the motor's operation is required. Brushless motors are seen

nowadays in very many computer applications, they for example rotate normal PC fans, hard

disks and disk drives.

Sometimes the rotation direction needs to be changed. In normal permanent magnet motors, this

rotation is changed by changing the polarity of operating power (for example by switching from

negative power supply to positive or by inter-changing the power terminals going to power

supply). This direction changing is typically implemented using relay or a circuit called an H

bridge. There are some typical characteristics on "brush-type" DC motors.

When a DC motor is straight to a battery (with no controller), it draws a large surge current when

connected up. The surge is caused because the motor, when it is turning, acts as a generator. The

generated voltage is directly proportional to the speed of the motor. The current through the motor

is controlled by the difference between the battery voltage and the motor's generated voltage

(otherwise called back EMF). When the motor is first connected up to the battery (with no motor

speed controller) there is no back EMF.

So the current is controlled only by the battery voltage, motor resistance (and inductance) and the

battery leads. Without any back emf the motor, before it starts to turn, therefore draws the large

surge current. When a motor speed controller is used, it varies the voltage fed to the motor.

Initially, at zero speed, the controller will feed no voltage to the motor, so no current flows. As the

motor speed controller's output voltage increases, the motor will start to turn. At first the voltage

fed to the motor is small, so the current is also small, and as the motor speed controller's voltage

rises, so too does the motor's back EMF. The result is that the initial current surge is removed,acceleration is smooth and fully under control

Motor speed control of DC motor is nothing new. A simplest method to control the rotation speed

of a DC motor is to control it's driving voltage. The higher the voltage is, the higher speed the

motor tries to reach. In many applications a simple voltage regulation would cause lots of power

loss on control circuit, so a pulse width modulation method (PWM)is used in many DC motor

controlling applications. In the basic Pulse Width Modulation (PWM) method, the operating

power to the motors is turned on and off to modulate the current to the motor. The ratio of "on"

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time to "off" time is what determines the speed of the motor. When doing PWM controlling, keep

in mind that a motor is a low pass device.

The reason is that a motor is mainly a large inductor. It is not capable of passing high frequency

energy, and hence will not perform well using high frequencies. Reasonably low frequencies are

required, and then PWM techniques will work. Lower frequencies are generally better than higher

frequencies, but PWM stops being effective at too low a frequency. The idea that a lowerfrequency PWM works better simply reflects that the "on" cycle needs to be pretty wide before

the motor will draw any current (because of motor inductance). A higher PWM frequency will

work fine if you hang a large capacitor across the motor or short the motor out on the "off" cycle

(e.g. power/brake pwm) The reason for this is that short pulses will not allow much current to

flow before being cut off. Then the current that did flow is dissipated as an inductive kick -

probably as heat through the fly-back diodes.

The capacitor integrates the pulse and provides a longer, but lower, current flow through the

motor after the driver is cut off. There is not inductive kick either, since the current flow isn't

being cut off. Knowing the low pass roll-off frequency of the motor helps to determine an

optimum frequency for operating PWM. Try testing your motor with a square duty cycle using a

variable frequency, and then observe the drop in torque as the frequency is increased. This

technique can help determine the roll off point as far as power efficiency is concerned.

Besides "brush-type" DC motors, there is another DC motor type: brushless DC motor. Brushless

DC motors rely on the external power drive to perform the commutation of stationary copper

winding on the stator. This changing stator field makes the permanent magnet rotor to rotate. A

brushless permanent magnet motor is the highest performing motor in terms of torque / vs. weight

or efficiency. Brushless motors are usually the most expensive type of motor.

Electronically commutated, brush-less DC motor systems are widely used as drives for blowers

and fans used in electronics, telecommunications and industrial equipment applications. There is

wide variety of different brush-less motors for various applications. Some are designed to rotate at

constant speed (those used in disk drives) and the speed of some can be controlled by varying the

voltage applied to them (usually the motors used in fans).

Some brushless DC motors have a built-in tachometer which gives out pulses as the motor rotates

(this applies to both disk drive motors and some computer fans). In general, users select brush-

type DC motors when low system cost is a priority, and brushless motors to fulfill otherrequirements (such as maintenance-free operation, high speeds, and explosive environments

where sparking could be hazardous). Brush type DC motors are used in very many battery

powered appliances. Brushless DC motors are commonly used in applications like DC powered

fans and disk drive rotation motor

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For DC motors because the direction of current the equation will be

Vs = E + IaRa Ia = I1 + If

Vs : Supply Voltage Ia : armature current If : field current

E : back e.m.f Ra : armature resistance

Another equation for DC motor is

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E generated e.m.f

P no. of pole pairs

Flux per pole

N speed per second (rps)

Z number of armature conductors

C number of parallel path

There are 2 types of armature windings . they are wave winding & lap winding . In this

equation C depends on that , that means in wave winding C = 2 & in lap winding C = 2P .

3.4 PIC microcontrollers and development system

PIC microcontroller is a processor with built in memory and RAM. It can use to control specific

project. It has separate external RAM, ROM and peripheral chip. PIC is a very powerful device

and it has many useful built in modules like EEPROM, Timers, Analogue Comparators, UART

and etc..

Its applications are

Frequency counter : using the internal timers and reporting through UART (RS232) or output to

LCD.

Capacitance meter : analogue comparator oscillator.

Event timer : using internal timers.

Event data logger: capturing analogue data using an internal ADC and using the internal

EEPROM for storing data (using an external I2C for high data storage capacity.

Servo controller (Control through UART) : using the internal PWM module or using a software

created PWM.

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Features

In fact a PIC microcontroller is an amazingly powerful fully featuredprocessor with internal

RAM, EEROM FLASH memory and peripherals. One of the smallest ones occupies the space of

a 555 timer but has a 10bit ADC, 1k of memory, 2 timers, high current I/O ports a comparator a

watch dog timer... I could go on as there is more!

Programming

One of the most useful features of a PIC microcontroller is that you can re-program them as they

use flash memory (if you choose a part with an F in the part number e.g. 12F675 not 12C509).

You can also use the ICSP serial interface built into each PIC Microcontroller for programming

and even do programming while it's still plugged into the circuit!

You can either program a PIC microcontroller using assembler or a high level language and I

recommend using a high level languagesuch as C as it ismuch easier to use (after an initial

learning curve). Once you have learned the high level language you are not forced to use the

same processor e.g. you could go to an AVR or Dallas microcontroller and still use the same high

level language.

Input / Output - I/O

A PIC Microcontroller can control outputs and react to inputs

e.g. It could drive a relay or read input buttons.

With the larger devices it's possible to drive LCDs or seven segment displays with very few

control lines as all the work is done inside the PIC microcontroller.

Comparing afrequency counterto discrete web designs It will find two or three chips for the

microcontroller design and ten or more for a discrete design. So using those saves prototype

design effort as you can use built in peripherals to take care of lots of the circuit operation.

Many now have a built in ADC so you can read analogue signal levels so we don't need to add an

external devices e.g. It can be read anLM35 temperature sensordirectly with no interface logic.

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Peripherals

The PIC microcontroller has many built in peripherals and this can make using them quite

daunting at first which is why I have made this introductory page with a summary of each major

peripheral block.

At the end is a short summary of themain devices used in projectsshown on this site.

The best way to start is to learn about the main features of a chip and then begin to use each

peripheral in a project. I think learning by doing is the best way.

Designing Criteria

4.1 ALU operation table

M S1 S0 Functions Xi (Logic

Extender)

Yi(Arithmetic

Extender)

C0

Logic operations

0 0 0 (Ai . Bi)' ai'ORbi' 0 0

0 0 1 Ai Bi ai XOR bi 0 0

0 1 0 (Ai + Bi)' ai' andbi' 0 0

0 1 1 (Ai Bi)' ai XNORbi 0 0

Arithmetic operations

1 0 0 Ai + Bi + 1 ai bi 1

1 0 1 Ai + Bi' ai bi' 0

1 1 0 Ai + 1 ai 0 1

1 1 1 Ai'+ Bi ai' bi 0

4.1.1 Logic Extender Unit

Truth table of logic extender

M S1 S0 Xi (Logic Extender)

0 0 0 (Ai . Bi)'

0 0 1 Ai Bi

0 1 0 (Ai + Bi)'

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0 1 1 (Ai Bi)'

1 0 0 Ai

1 0 1 Ai

1 1 0 Ai

1 1 1 Ai'

Kanough Map of Logic Extender

Excitation Equation of Logic extender

Xi = M' Ai' Bi' S1 + M' Ai' S1' S0' + M' Ai' Bi S1' + Ai Bi' S1' + M' Ai Bi S1 S0 +

M Ai S1' + M Ai S0' + M Ai' S1 S0

Output circuit of Logic extender

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M S 1 S 0 A B

M

N O T

S 1

N O T

S 0

N O T

A

N O T

B

N O T

U 1

A N D 4

U 2

A N D 4

U 3

A N D 4U 4

A N D 4

U 5

A N D 3U 6

A N D 4

U 7

A N D 5

U 8

A N D 4

U 1 4

O R 8

Figure 4.1.1.1

4.1.2 Arithmetic extender unit

Truth table of Arithmetic extender

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Kanough Map of Arithmetic extender

Excitation equation Arithmetic extender

Yi = M Bi S1' S0' + M Bi S1 S0 + M Bi' S1' S0

Circuit Arithmetic extender

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M S1 S0 Yi0 0 0 0

0 0 1 0

0 1 0 0

0 1 1 0

1 0 0 Bi1 0 1 Bi'

1 1 0 0

1 1 1 Bi


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M S1 S0 B

U2

NOT

U3

NOT

U4

NOT

U5

AND4U6

AND4

U7

AND4

U8

OR3

Figure 4.1.2.1

4.1.3 Carry Extender Unit

Truth table of Carry extender

M S1 S0 C0

0 0 0 0

0 0 1 0

0 1 0 0

0 1 1 0

1 0 0 1

1 0 1 0

1 1 0 1

1 1 1 0

Kanough map of Carry extender

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Excitation equation of Carry extender

C0= M S0'

Circuit of Carry extender

M S0

U1

AND2

U2

NOT

Figure 4.1.3.1

4.1.4 The Resultant Circuit of the Arithmetic Logic Unit

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Figure 4.1.4.1

5. Software Implementation

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5.1. Flow chart of DC motor control program

Figure 5.1.1

Implementation and simulate the circuit

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PIC16F877A microcontroller is used here to design the circuit. The source code is written in C

language and its compiled by using CCS Compiler. Thereafter circuit is designed and simulates

using proteus ISIS 7 Professional software. The microcontroller input voltage is low and it is

controlled by very low voltage. Around 0.5mV it can be star, stop and control the motor. Using

low voltage and power consumption can have a high efficiency of the device. Using delay

function by coding the motor functioning time can be set.

5.2. C program implementation

The C language source code which is used to program

#include "16F877A.h"

#use delay (clock=1000000)

void main()

{

int x;

int y;

output_D(0);

output_D(1);

while(1)

{

x=input(PIN_c0);

y=input(PIN_c1);

if(x==1)output_high(PIN_D0);

delay_ms(250);

if(x==0)output_low(PIN_D0);

if(y==1)output_high(PIN_D1);

if(y==0)output_low(PIN_D1);

delay_ms(450);

}

}

Screenshot of the CCS Compiler.

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Figure 5.2.1

5.3 Simulation with integrated development environment (IDE)

The proteus software screen shots

Figure 5.3.1

When both switches are turned off and start the system, the motor go to rest.

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Figure 5.3.2

When switch SW2 is turned on, the input C0 is high output D0 also high. Then motor start to

rotate clockwise

Figure 5.3.3

When switch SW2 is turned off and switch SW1 is turned on, the input C1 is high output D1 also

high. Then motor start to rotate anti-clockwise.

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Figure 5.3.4

When both switches are turned on both inputs and outputs are high. Then motor get voltage from

both sides and it goes to rest.

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Discussion

ALU

After making the truth table we can make the simulation circuit. But it will be very complicated

and hardware designing cost also will be high. Also the circuit size become larger and it willdefault in application. We can simplify the circuit using kanough map from the truth table. When

we use the kanough map we can get simplified equations and we can design the simplified circuit

using those equations.

When we designing a simplified circuit it reduced circuit building cost and get more efficiency

circuit. When it comes to industrial the circuit size will be very smaller and its easier to portable.

Also the power cost wil be reduced.

DC Motor

Here we select a simple DC motor control system. Using two switch rotate the motor clock and

anti-clockwise and stop/start the motor. When the switch one is on the motor right side terminal

get voltage and motor start to rotate. Here we used series wound motor. So if the switch is open

for long time the rotating speed goes to infinite. It is not suitable for application and it will be very

harmful.

The input switch is not directly connected to the motor and its designed for low voltage.

Otherwise the input voltage can be high. The reason here is when we use the low input voltage the

transient effect also will be low.

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Conclusions

ALU

A 4 bit ALU has capability to perform only eight operations at a time. The logic extender of this

ALU is little bit complicated comparing other. Because it is performing for main operations OR,AND, NOT and XOR. There for inputs (M, S1, S0 ,ai , bi). So 32 bit Kanough map has to be used

to solve and get the equations. Therefore it needs lot of processing and big circuit. But arithmetic

and carry extender require small circuit. Carry extender is a very small circuit with single gate

operation. This 4 bit ALU has a ability of performing any mathematical operation such as

addition, subtraction, multiplication and division and logical operations such as AND, OR,

NOT.Etc.

DC Motor

The DC motor controller design here using PIC microcontroller and it can controlled by PIC very

successfully. In the control system here program PIC microcontroller by C language and compiled

it using CCS Compiler successfully and it design the whole system on proteus ISIS 7 Professional

software and installed the compiled C file into PIC successfully. After when play system it plays

completely successfully and able to stop/star and change the direction of the motor.

This type of motor controller system is very important in this generation. Because the PICprogram can be changed nay time easily according to the applications. When simulating the

program it gets real working condition in the microcontroller. A DC motor control using a PIC

microcontroller is a better choice and it is efficiency way of control the system.

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Reference

1. A PIC microcontroller introduction [Online] [Accessed 2012.may.26] http://www.best-

microcontroller-projects.com/pic-microcontroller.html

2.Principles of operation of DC electric motors. 2012. Principles of operation of DC electric

motors. [ONLINE] [Accessed 26 May 2012] http://www.pc-control.co.uk/dc-motors.htm

3.Bates, M(2008) programming 8-bit PIC Microcontrollers in C with interactive hardware

simulation

4.Enoch Hwang (2006).Digital Logic and Microprocessor Design with VHDL, chapter 4. .

United Kingdom .

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A202SE Microcomputer System Coursework

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