106168730 Larfereser Communicfrefefation 68

8/11/2019 106168730 Larfereser Communicfrefefation 68

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A PROJECT REPORT

ON

LASER COMMUNICATION

Bachelor of Technology

In

Electronics & Communication

2011-2012

Project Incharge : Submitted By:

Mr. Saurabh Sharma Akshat Mitta !0"2#2$100%&Miss. S'ati Singh (eha Singh !0"2#2$102)&

Shrey Agar'a !0"2#2$10$#&

Mudit *ander!0"2#2$1+0+&

Bharti ,oshi !0"2#221010&

eartment o/ ectronics ommunication

M*34 I(S4I434 56 47(5859;

M*34 !3.P.&


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*4I6IA4

This is to certify that or! hich is "eing #resente$ in the #ro%ect

entitle$ LASER COMMUNICATIONsu"mitte$ "y Mr Akshat MittaMiss (eha Singh' Mr Shrey Agar'a' Mr Mudit *ander' Miss Bharti

,oshi stu$ent of final year BTech In ELECTRONICS &

COMMUNICATION in #artial fulfillment of the re(uirement for aar$ of

the $egree of BTech in ELECTRONICS & COMMUNICATION is a recor$

of stu$ents or! carrie$ out "y them un$er my gui$ance an$ su#er)ision

As #er the can$i$ates $eclaration this or! has not "een su"mitte$

elsehere for the aar$ of any other $egree

ated: 2< Ari 2012 Signature of *ro%ect +ui$e

Pace: Meerut (ame, Miss Sati Singh

esignation,843**

Signature of *ro%ect Incharge Signature of -O.


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A=(5>89M(4

?Enthusiasm is the feet of all progresses, with it there is

accomplishment and without it there are only slits alibis.@

Ac!nole$gment is not a ritual "ut is certainly an im#ortant thing forthe successful com#letion of the #ro%ect At the time hen e ere ma$e to

!no a"out the #ro%ect' it as really )ery tough to #rocee$ further as e

ere to $e)elo# the same on a #latform' hich as ne to us More so' the

co$ing #art seeme$ so tric!y that it seeme$ to "e im#ossi"le for us to

com#lete the or! ithin the gi)en $uration

/e really feel in$e"te$ in ac!nole$ging the organi0ational su##ort

an$ encouragement recei)e$ from the management of our college.

The tas! of $e)elo#ing this system oul$ not ha)e "een #ossi"leithout the constant hel# of our mentors /e ta!e this o##ortunity to

e1#ress our #rofoun$ sense of gratitu$e an$ res#ect to those ho hel#e$ us

throughout the $uration of this #ro%ect

/e e1#ress our gratitu$e to Mr. Saurabh Sharma !7.5.;MI4& Miss.

S'ati Singh!8ecturer;MI4& /e oul$ again li!e to than! all of them for

gi)ing their )alua"le time to us in $e)elo#ing this #ro%ect

ated:2< Ari 2012 Mr A!shat Mittal

Pace: Meerut Miss Neha Singh

Mr Shrey Agaral

Mr Mu$it Ran$er

Miss Bharti 2oshi


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TABLE OF CONTENTS

INTRODUCTION

PLATFORM USED

AIM OF THE PROJECT

BLOCK DIAGRAM

WORKING OF THE PROJECT

CIRCUIT DIAGRAM

COMPONENT LIST

CIRCUIT DESCRIPTION

PCB LAYOUT

STEPS FOR MAKING PCB

PROGRAMMING


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SENSING UNIT DESCRIPTION

COMPONENTS DESCRIPTION

APPLICATION

CONCLUSION

REFERENCE

Intro$uction


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I(4*534I5(,

Laser communications systems are ireless connections through the

atmos#here They or! similarly to fi"er o#tic lin!s' e1ce#t the "eam is

transmitte$ through free s#ace /hile the transmitter an$ recei)er must

re(uire line3of3sight con$itions' they ha)e the "enefit of eliminating the nee$

for "roa$cast rights an$ "urie$ ca"les Laser communications systems can "e

easily $e#loye$ since they are ine1#ensi)e' small' lo #oer an$ $o not

re(uire any ra$io interference stu$ies The carrier use$ for the transmission

signal is ty#ically generate$ "y a laser $io$e To #arallel "eams are

nee$e$' one for transmission an$ one for rece#tion .ue to "u$get


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restrictions' the system im#lemente$ in this #ro%ect is only one ay

This #ro%ect is microcontroller "ase$ Laser communication system

use$ for the successful transmission of $ata In this #ro%ect using to

microcontroller 'e are transmitting $ata from one en$ using laser

transmitter an$ at other en$ recei)e$ "y laser recei)er hich is connecte$ to

the #in of microcontroller 'here the transmitte$ as ell as recei)e$ $ata

$is#laye$ on lc$

Platform used


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7ard'are reuirements,

1& Microcontroller AT45C67

2& L.R

$& LM8496 Regulator

+& *oer Su##ly

)& Resistors

%& Ca#acitors


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AIM OF THEPROJECT


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The Aim of this #ro%ect is to $esign a communication system through

Laser'a laser $io$e at the transmitting en$ act as a trans$user to con)ert the

$igital $ata into laser form an$ transmitte$ 'at the recei)ing en$ a laser

transistor con)ert the laser $ata into $igital form

-ere the moti)e of using Laser is that /hile the transmitter an$

recei)er must re(uire line3of3sight con$itions' they ha)e the "enefit of

eliminating the nee$ for "roa$cast rights an$ "urie$ ca"les Laser

communications systems can "e easily $e#loye$ since they are ine1#ensi)e'

small' lo #oer an$ $o not re(uire any ra$io interference stu$ies


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Block diagram


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Laser communication

TRANSMITTER

TRANSMITTER

LASER DIODE

SUPPLYSECTION

MICROCONTROLLER

Commun!"#on

DISPLAY SECTIONUSING

LCD


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Receiver

MICRO CONTROLLER 89C51

RECEI$ER

LDR

DISPLAY SECTIONUSING

LCDSUPPLY

SECTION


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WORKING OFTHE PROJECT


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There are to microcontroller one at sen$ing en$ an$ the other at

recei)ing en$ Laser transmitter is connecte$ to the #in of the

microcontroller at the sen$ing en$ an$ the LASER recei)er is

connecte$ to microcontroller at recei)er en$hene)er a #erson is

ishing to sen$ the $ata the microcontroller ma!e the laser transmitter

to sen$ the fre(uency corres#on$ing to that $ata an$ at recei)er en$

that fre(uency can change to the original $ata form hich ill $is#lay

on the lc$ connecte$ to the #in of the microcontrollerin this ay the

function of transmitting the $ata through laser recei)er an$

transmitter ha)e "een com#lete$


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CIRCUIT

DIAGRAM


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Attach the hard

copy of the cktda!ra"


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Component list


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Attach hard copy of

Component list


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CIRCUITDE#CRIPTION


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POWER SPPL! SECTION"

Co$%%t% of&1% RLMT Connector&&& I# ' " !onn(!#o) u'(* #o !onn(!#

#+( '#(, *o-n #)"n'.o)m() #o #+( /)*0( )(!#.()%

% Bri#$e Recti%ier &&& I# ' " .u22 -"3( )(!#.() u'(* #o!on3()# "! n#o *! 4 9&153 "! m"*( / #)"n'.o)m() '!on3()#(* n#o *! -#+ #+( +(2, o. )(!#.()%

6% Ca&acitor" &&&&&I# ' "n (2(!#)o2#! !","!#o) o.)"#n0 1777M65$ u'(* #o )(mo3( #+( ),,2('% C","!#o)' #+( !om,on(n# u'(* #o ,"'' #+( "! "n* /2o! #+( *!%

:% Re$u'ator" &&&&LM;875 ' u'(* #o 03( " .u(n! '+0+?',('@%

So #+( ou#,u# o. 'u,,2 '(!#on ' 53 )(0u2"#(* *!%


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MICROCONTROLLER SECTION"

R(>u)(' #+)(( !onn(!#on' #o /( 'u!!(''.u22 *on( .o)#' o,()"#on #o /(0n%

1% (v su&&'*" T+' 53 'u,,2 ' )(>u)(* .o) #+(!on#)o22() #o 0(# '#")# -+!+ ' ,)o3*(* .)om #+( ,o-()'u,,2 '(!#on% T+' 'u,,2 ' ,)o3*(* "# ,n no%61"n*:7 o. #+( 89!51 !on#)o22()%

% Cr*sta' Osci''ator" A !)'#"2 o'!22"#o) o. 1 MH '!onn(!#(* "# ,n no%194u(n! .o) #+( !on#)o22()% T+( !)'#"2 o'!22"#o)-o)' on ,(o(2(!#)! (..(!#%T+( !2o! 0(n()"#(* 'u'(* #o *(#()mn( #+( ,)o!(''n0 ',((* o. #+(!on#)o22()% T-o !","!#o)' ")( "2'o !onn(!#(* on( (n*-#+ #+( o'!22"#o) -+2( #+( o#+() (n* ' !onn(!#(* -#+#+( 0)oun*% A' # ' )(!omm(n*(* n #+( /oo #o!onn(!# #-o !()"m! !","!#o) o. 7 ,.:7,. #o'#"/2( #+( !2o! 0(n()"#(*%

6% Reset section" I# !on''#' o. "n )! n(#-o)!on''#n0 o. 17M65$ !","!#o) "n* on( )(''#"n!( o.1% T+' '(!#on ' u'(* #o )('(# #+( !on#)o22()!onn(!#(* "# ,n no%9 o. AT89!51%

+ISPLA! SECTION"


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LC+,LI-I+ CR!STAL +ISPLA!)

MICROCONTROLLER BASED LCD DISPLAY 4#+' ,)o(!# ' "n (m/(**(*,)o(!# % Em/(**(* ' #+( !om/n"#on o. 'o.#-")( "n* +")*-")( /(.o)(*('0nn0 "n (m/(**(* ,)o(!# # ' #+( .)'# '#(, #o *('0n #+( ,)o,()+")*-")( .o) #+( *(')(* ",,2!"#on% H()( -( ")( n#()."!n0 #+( LCD4

LIUID CRYSTAL DISPLAY -#+ #+( M!)o!on#)o22()4 -( ")( u'n0 ATMEL'()(' 51 !on#)o22() 89!51 !on#)o22()% I# ' " :7 ,n IC4 #+( .)'# '#(, -+2(*('0nn0 +")*-")( ' #o *('0n #+( )(>u)(* ,o-() 'u,,2 "' #+(!on#)o22() o,()"#(' on 5 3 'u,,2 'o .)'# -( +"3( #o *('0n #+()(0u2"#(* 'u,,2 -#+ #+( +(2, o. #)"n'.o)m()4 )(0u2"#o) "n* .2#()n0!","!#o)%N(


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)(2" !"n *"m"0( #+( ,)o!(''o) -+(n #+( #)"n''#o) BC5:;' on% A ,u22 *o-n )(''#o) o. 3"2u( ' "2'o u'(*%

PC' (A)OUT


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Attach the hardcopy of the


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co"po$e$t

*ayo+t

Attach the hardcopy of the pc,

*ayo+t


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#TEP# FORMAKING PC'


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P)(,")( #+( 2"ou# o. #+( !)!u# ?,o'#3(@%

Cu# #+( ,+o#o.2m ?'20+#2 /00()@ o. #+( '( o. #+( 2"ou#%

P2"!( #+( 2"ou# n #+( ,+o#o,)n#() m"!+n( -#+ #+(,+o#o.2m "/o3( #% M"( 'u)( #+"# #+( /)om*( ?*")@ '*( o.#+( .2m ' n !on#"!# -#+ #+( 2"ou#%

S-#!+ on #+( m"!+n( / ,)(''n0 #+( ,u'+ /u##on .o) 5 '(!%

D, #+( .2m n #+( 'o2u#on ,)(,")(* ?*(3(2o,()@ / mu"n##(' n -"#()%

No- !2("n #+( .2m / ,2"!n0 # n #+( #)" !on#"nn0 -"#() .o)

1 mn%

A.#() #+'4 *, #+( .2m n #+( .u* ,+o#o)(''#4 -#+ #+( +(2, o. *,!o"# m"!+n(%

No- !2, #+( PCB n(


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No- ,2"!( #+( n(0"#3( on #+( #o, o. #+( PCB n #+( U$m"!+n(4 '(# #+( #m() .o) "/ou# %5 mnu#( "n* '-#!+ on #+(U$ 20+# "# #+( #o,%

T"( #+( LPR *(3(2o,() n " !on#"n() "n* )0o)ou'2 mo3( #+(PCB n #%

A.#() #+'4 -"'+ # -#+ -"#() 3() 0(n#2%

T+(n ",,2 LPR *( on # -#+ #+( +(2, o. " *)o,,() 'o #+"# # '!om,2(#(2 !o3()(* / #%

No- !2"m, #+( PCB n #+( (#!+n0 m"!+n( #+"# !on#"n' .())!!+2o)*( 'o2u#on .o) "/ou# 17 mnu#('%

A.#() (#!+n04 -"'+ #+( PCB -#+ -"#()4 -,( # " *) !2o#+'o.#2%

Fn"22 )u/ #+( PCB -#+ " '#((2 -oo24 "n* #+( PCB ' )("*%


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Pro!ra""$!


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Attach hardcopy of

pro!ra""$!


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#EN#ING UNITDE#CRIPTION


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Laser transmitter

Laser receiver


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A aser diodeis a laserhere the acti)e me$ium is a semicon$uctorsimilar

to that foun$ in a light3emitting $io$e The most common an$ #ractical ty#e

of laser $io$e is forme$ from a#3n %unctionan$ #oere$ "y in%ecte$ electric

current These $e)ices are sometimes referre$ to as injection laser diodesto

$istinguish them from


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emission is necessary to initiate laser oscillation' "ut it is one among se)eral

sources of inefficiency once the laser is oscillating

The $ifference "eteen the #hoton3emitting semicon$uctor laser an$

con)entional #honon3emitting


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stimulate$ emission causes gain in an o#tical a)e


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enough' a$$itional side modesmay also lase Some laser $io$es' such as

most )isi"le lasers' o#erate at a single a)elength' "ut that a)elength is

unsta"le an$ changes $ue to fluctuations in current or tem#erature

.ue to $iffraction' the "eam $i)erges


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MI*55(4*588* A4"#)1

6eatures

F Com#ati"le ith MCS367G *ro$ucts

F 4H Bytes of In3System Re #rogramma"le lash Memory

F En$urance, 7'999 /riteErase Cycles

F ully Static O#eration, 9 -0 to JK M-0

F Three3le)el *rogram Memory Loc!

F J6@ 1 43"it Internal RAM

F J *rogramma"le IO Lines

FThree 7@3"it TimerCounters

F Eight Interru#t Sources

F *rogramma"le Serial ChannelF Lo3#oer I$le an$ *oer3$on Mo$es


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.ESCRI*TION

The AT45C6J is a lo3#oer' high3#erformance CMOS 43"it microcom#uter 4H"ytes of

lash #rogramma"le an$ erasa"le rea$ only memory


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Pin escrition

G

Su##ly )oltage

9(

+roun$

Port 0

Port 0 is an "-bit oen drain bi-directiona IC5 ort. As an outut ort; each in cansink eight 448 inuts. >hen 1s are 'ritten to ort 0 ins; the ins can be used as

high imedance inuts.

*ort 9 can also "e configure$ to "e the multi#le1e$ lo or$er a$$ress$ata

"us $uring accesses to e1ternal #rogram an$ $ata memory In this mo$e' *9

has internal #ull3u#s

*ort 9 also recei)es the co$e "ytes $uring lash #rogramming an$ out#uts

the co$e "ytes $uring #rogram )erification E1ternal #ull3u#s are re(uire$

$uring #rogram )erification

Port 1

*ort 7 is an 43"it "i3$irectional IO #ort ith internal #ull3u#s The *ort 7

out#ut "uffers can sin!source four TTL in#uts /hen 7s are ritten to *ort

7 #ins' they are #ulle$ high "y the internal #ull3u#s an$ can "e use$ as

in#uts As in#uts' *ort 7 #ins that are e1ternally "eing #ulle$ lo ill source

current


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Port 2

*ort J is an 43"it "i3$irectional IO #ort ith internal #ull3u#s The *ort J

out#ut "uffers can sin!source four TTL in#uts /hen 7s are ritten to *ort

J #ins' they are #ulle$ high "y the internal #ull3u#s an$ can "e use$ as

in#uts As in#uts' *ort J #ins that are e1ternally "eing #ulle$ lo ill source

current


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*S4

*eset inut. A high on this in /or t'o machine cyces 'hie the osciator is running

resets the deice.

A8CP*59

A$$ress Latch Ena"le is an out#ut #ulse for latching the lo "yte of the a$$ress $uring

accesses to e1ternal memory This #in is also the #rogram #ulse in#ut


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Note' hoe)er' that if loc! "it 7 is #rogramme$' EA ill "e internally

latche$ on reset

EA shoul$ "e stra##e$ to CC for internal #rogram e1ecutions This #in

also recei)es the 7J3)olt #rogramming ena"le )oltage


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Secia 6unction *egisters

A ma# of the on3chi# memory area calle$ the S#ecial unction Register


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4imer 0 and 1

Timer 9 an$ Timer 7 in the AT45C6J o#erate the same ay as Timer 9 an$ Timer 7 in the

T45C67

4imer 2

Timer J is a 7@3"it TimerCounter that can o#erate as either a timer or an

e)ent counter The ty#e of o#eration is selecte$ "y "it CTJ in the SR

TJCON


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oscillator #erio$s' the count rate is 77J of the oscillator in#ut #in' TJ In this

function' the e1ternal in#ut is sam#le$ $uring S6*J of e)ery machine cycle

/hen the sam#les sho a high in one cycle an$ a lo in the ne1t cycle' the

count is incremente$ The ne count )alue a##ears in the register $uring

S*7 of the cycle folloing the one in hich

the transition as $etecte$ Since to machine cycles


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Auto-reoad !3 or o'n ounter&

Timer J can "e #rogramme$ to count u# or $on hen configure$ in its 7@3"it auto3reloa$

mo$e This feature is in)o!e$ "y the.CEN


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Baud *ate 9enerator

Timer J is selecte$ as the "au$ rate generator "y setting TCLH an$or RCLH

in TJCON


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Programmabe ock 5ut

A 69 $uty cycle cloc! can "e #rogramme$ to come out on *79' as shon

in igure 6 This #in' "esi$es "eing a regular IO #in' has to alternate

functions It can "e #rogramme$ to in#ut the e1ternal cloc! for

TimerCounter J or to out#ut a 69 $uty cycle cloc! ranging from @7 -0 to

K M-0 at a 7@ M-0 o#erating fre(uency To configure the TimerCounter J

as a cloc! generator' "it CTJ


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3A*4

The UART in the AT45C6J o#erates the same ay as the UART in the AT45C67

Interruts

The AT45C6J has a total of si1 interru#t )ectors, to e1ternal interru#ts


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5sciator haracteristics

H4A81 and H4A82 are the inut and outut; resectiey; o/ an inerting ami/ier

that can be con/igured /or use as an on-chi osciator; as sho'n in 6igure


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har$are inhi"its access to internal RAM in this e)ent' "ut access to the #ort

#ins is not inhi"ite$ To eliminate the #ossi"ility of an une1#ecte$ rite to a

#ort #in hen i$le mo$e is terminate$ "y a reset' the instruction folloing

the one that in)o!es i$le mo$e shoul$ not rite to a #ort #in or to e1ternal

memory

Po'er-do'n Mode

In the #oer3$on mo$e' the oscillator is sto##e$' an$ the instruction that

in)o!es #oer3$on is the last instruction e1ecute$ The on3chi# RAM an$

S#ecial unction Registers retain their )alues until the #oer3$on mo$e is

terminate$ The only e1it from #oer3$on is a har$are reset Reset

re$efines the SR s "ut $oes not change the on3chi# RAM The reset shoul$

not "e culti)ate$ "efore CC is restore$ to its normal o#erating le)el an$

must "e hel$ acti)e long enough to allo the oscillator to restart an$

sta"ili0e


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AC Characteristics

Un$er o#erating con$itions' loa$ ca#acitance for *ort 9' ALE*RO+' an$

*SEN Q 799 # loa$ ca#acitance for all other

out#uts Q 49 #


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Note, 7 AC In#uts $uring testing are $ri)en at CC 3 96

for a logic 7 an$ 9K6 for a logic 9 Timing measurements

are ma$e at I- min for a logic 7 an$ IL ma1

for a logic 9

6oat >ae/orms


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Com#onent $escri#tion


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!","!#o) ' "**(*% T+( 'moo#+n0 !"n #+(n /( m,)o3(* /"**n0 "**#on"2 '#"0(' o. !","!#o))(''#o) ,")'4 o.#(n*on( on2 .o) 'u/&'u,,2(' #o !)#!"2 +0+&0"n !)!u#' #+"##(n* #o /( '(n'#3( #o 'u,,2 3o2#"0( no'(%4o'ta$e Re$u'ators

A vo'ta$e re$u'ator ' "n (2(!#)!"2 )(0u2"#o)*('0n(* #o"u#om"#!"22 m"n#"n " !on'#"n# 3o2#"0(2(3(2% I# m" u'("n (2(!#)om(!+"n!"2 m(!+"n'm4 o) ,"''3( o) "!#3((2(!#)on! !om,on(n#'% D(,(n*n0 on #+( *('0n4 # m" /(u'(* #o )(0u2"#( on( o) mo)( AC o) DC3o2#"0('% W#+ #+((

23531 LM617 ,6Termina' A#8usta9'e Re$u'ator)

+escri&tionT+( LM61; ' "n "*u'#"/2( #+)((()mn"2 ,o'#3(&3o2#"0()(0u2"#o) !","/2( o. 'u,,2n0 mo)( #+"n 1%5 A o3() "nou#,u#&3o2#"0( )"n0( o. 1% $ #o 6; $% I# ' (


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,)o#(!#on )(m"n' .u22 .un!#on"24 (3(n . #+( ADJUST#()mn"2 ' *'!onn(!#(*%

Fi$ure 1: TOP IC vie o% LM 617

T+( LM61; ' 3()'"#2( n #' ",,2!"#on'4 n!2u*n0 u'(' n,)o0)"mm"/2( ou#,u# )(0u2"#on "n* 2o!"2 on&!")*)(0u2"#on% O)4 / !onn(!#n0 " .


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Fi$ure 17" A#8usta9'e 4o'ta$e Re$u'ator

23532 LM7;. ,6Termina' Fi


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A2#+ou0+ *('0n(* ,)m")2 "' .


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Fi$ure 1>" Fi


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Li?ui# cr*sta' #is&'a*,LC+)

A li(ui$ crystal$is#lay


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"eteen #arallel #olari0ers' in hich case the "right an$ $ar! states are

re)erse$

Both the li(ui$ crystal material an$ the alignment layer material contain

ioniccom#oun$s If an electric fiel$ of one #articular #olarity is a##lie$ for

a long #erio$ of time' this ionic material is attracte$ to the surfaces an$$egra$es the $e)ice #erformance This is a)oi$e$ "y a##lying either an

alternating current' or "y re)ersing the #olarity of the electric fiel$ as the

$e)ice is a$$resse$


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6igure 20:8 Pictoria Gie'

2.).1 8 Standards

re(uently' an 4967 #rogram must interact ith the outsi$e orl$ using

in#ut an$ out#ut $e)ices that communicate $irectly ith a human "eing Oneof the most common $e)ices attache$ to an 4967 is an LC. $is#lay Some

of the most common LC.s connecte$ to the 4967 are 7@1J an$ J91J

$is#lays This means 7@ characters #er line "y J lines an$ J9 characters #er

line "y J lines' res#ecti)ely ortunately' a )ery #o#ular stan$ar$ e1ists

hich allos us to communicate ith the )ast ma%ority of LC.s regar$less

of their manufacturer The stan$ar$ is referre$ to as -.KK849U' hich

refers to the controller chi# hich recei)es $ata from an e1ternal source


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The *>line is the ?Rea$/rite? control line /hen R/ is lo


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B< 3 P1.AI4J8routine to ait until the instruction is com#letely

e1ecute$ "y the LC. This ill assure that our #rogram gi)es the LC. the

time it nee$s to e1ecute instructions an$ also ma!es our #rogram com#ati"le

ith any LC.' regar$less of ho fast or slo it is

Programming 4i:The a"o)e routine $oes the %o" of aiting for the LC.'

"ut ere it to "e use$ in a real a##lication a )ery $efinite im#ro)ement

oul$ nee$ to "e ma$e, as ritten' if the LC. ne)er "ecomes ?not "usy? the

#rogram ill effecti)ely ?hang'? aiting for .B8 to go lo If this ne)er

ha##ens' the #rogram ill free0e Of course' this shoul$ ne)er ha##en an$

'onLt ha##en hen the har$are is or!ing #ro#erly But in a real

a##lication it oul$ "e ise to #ut some !in$ of time limit on the $elay33for

e1am#le' a ma1imum of J6@ attem#ts to ait for the "usy signal to go lo

This oul$ guarantee that e)en if the LC. har$are fails' the #rogram

oul$ not loc! u#

2.).% InitiaiEing the 8

Before you may really use the LC.' you must initiali0e an$ configure it

This is accom#lishe$ "y sen$ing a num"er of initiali0ation instructions to the

LC. The first instruction e sen$ must tell the LC. hether ell "e

communicating ith it ith an 43"it or K3"it $ata "us /e also select a 614

$ot character font These to o#tions are selecte$ "y sen$ing the comman$

4h to the LC. as a comman$ As you ill recall from the last section' e

mentione$ that the *Sline must "e lo if e are sen$ing a comman$ to the

LC. Thus' to sen$ this 4h comman$ to the LC. e must e1ecute the

folloing 4967 instructions,

8* *S

M5G A4A; K$"h

S4B (

8* (

8A88 >AI4J8


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Programming 4i:The LC. comman$ 4h is really the sum of a num"er

of o#tion "its The instruction itself is the instruction J9h


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8* (

8A88 >AI4J8

8* *S

M5G A4A; K0h

S4B (

8* (8A88 >AI4J8

8* *S

M5G A4A; K0%h

S4B (

8* (

8A88 >AI4J8

*4

-a)ing e1ecute$ this co$e the LC. ill "e fully initiali0e$ an$ rea$y for us

to sen$ $is#lay $ata to it

2.).< earing the isay

/hen the LC. is first initiali0e$' the screen shoul$ automatically "e cleare$

"y the KK849 controller -oe)er' its alays a goo$ i$ea to $o things

yourself so that you can "e com#letely sure that the $is#lay is the ay you

ant it Thus' its not a "a$ i$ea to clear the screen as the )ery first o#reation

after the LC. has "een initialie0$

An LC. comman$ e1ists to accom#lish this function Not su#risingly' it is

the comman$ 97h Since clearing the screen is a function e )ery li!ely ill

ish to call more than once' its a goo$ i$ea to ma!e it a su"routine,

8A*J8:

8* *S

M5G A4A; K01h

S4B (

8* (

8A88 >AI4J8

*4

-o that e)e ritten a ?Clear Screen? routine' e may clear the LC. at

any time "y sim#ly e1ecuting an 8A88 8A*J8

Programming 4i:E1ecuting the ?Clear Screen? instruction on the LC.

also #ositions the cursor in the u##er left3han$ corner as e oul$ e1#ect


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2.)." >riting 4eDt to the 8

No e get to the real meat of hat ere trying to $o, All this effort is

really so e can $is#lay te1t on the LC. Really' ere #retty much $oneOnce again' riting te1t to the LC. is something ell almost certainly ant

to $o o)er an$ o)er33so lets ma!e it a su"routine

>*I4J4H4:

S4B *S

M5G A4A; A

S4B (

8* (

8A88 >AI4J8

*4

The >*I4J4H4routine that e %ust rote ill sen$ the character in the

accumulator to the LC. hich ill' in turn' $is#lay it Thus to $is#lay te1t

on the LC. all e nee$ to $o is loa$ the accumulator ith the "yte to

$is#lay an$ ma!e a call to this routine *retty easy' huhV

2.).# A Program: 7885 >5*8

No that e ha)e all the com#onent su"routines ritten' riting the classic

?-ello /orl$? #rogram33hich $is#lays the te1t ?-ello /orl$? on the LC.

is a relati)ely tri)ial matter Consi$er,

8A88 I(I4J8

8A88 8A*J8


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M5G A;KL7L

8A88 >*I4J4H4

M5G A;KLL

8A88 >*I4J4H4

M5G A;KL8L

8A88 >*I4J4H4M5G A;KL8L

8A88 >*I4J4H4

M5G A;KL5L

8A88 >*I4J4H4

M5G A;KL L

8A88 >*I4J4H4

M5G A;KL>L

8A88 >*I4J4H4

M5G A;KL5L

8A88 >*I4J4H4

M5G A;KL*L

8A88 >*I4J4H4

M5G A;KL8L

8A88 >*I4J4H4

M5G A;KLL

8A88 >*I4J4H4

The a"o)e ?-ello /orl$? #rogram shoul$' hen e1ecute$' initiali0e the

LC.' clear the LC. screen' an$ $is#lay ?-ello /orl$? in the u##er left3han$ corner of the $is#lay


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2.).10 ursor Positioning

The a"o)e ?-ello /orl$? #rogram is sim#listic in the sense that it #rints its

te1t in the u##er left3han$ corner of the screen -oe)er' hat if e ante$to $is#lay the or$ ?-ello? in the u##er left3han$ corner "ut ante$ to

$is#lay the or$ ?/orl$? on the secon$ line at the tenth characterV This

soun$s sim#le33an$ actually' it is sim#le -oe)er' it re(uires a little more

un$erstan$ing of the $esign of the LC.

The KK849 contains a certain amount of memory hich is assigne$ to the

$is#lay All the te1t e rite to the KK849 is store$ in this memory' an$ the

KK849 su"se(uently rea$s this memory to $is#lay the te1t on the LC. itself

This memory can "e re#resente$ ith the folloing ?memory ma#?,

6igure 22: Memory Maing in 8

In the a"o)e memory ma#' the area sha$e$ in "lue is the )isi"le $is#lay Asyou can see' it measures 7@ characters #er line "y J lines The num"ers in

each "o1 is the memory a$$ress that corres#on$s to that screen #osition

Thus' the first character in the u##er left3han$ corner is at a$$ress 99h The

folloing character #osition


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must sen$ a ?Set Cursor *osition? instruction33the )alue of this comman$

ill "e 49h AI4J8

The a"o)e co$e ill #osition the cursor on line J' character 79 To $is#lay

?-ello? in the u##er left3han$ corner ith the or$ ?/orl$? on the secon$

line at character #osition 79 %ust re(uires us to insert the a"o)e co$e into our

e1isting ?-ello /orl$? #rogram

This results in the folloing,

8A88 I(I4J8

8A88 8A*J8

M5G A;KL7L

8A88 >*I4J4H4M5G A;KLL

8A88 >*I4J4H4

M5G A;KL8L

8A88 >*I4J4H4

M5G A;KL8L

8A88 >*I4J4H4

M5G A;KL5L

8A88 >*I4J4H4

8* *S

M5G A4A;K0Ah

S4B (

8* (

8A88 >AI4J8

M5G A;KL>L

8A88 >*I4J4H4

M5G A;KL5L


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8A88 >*I4J4H4

M5G A;KL*L

8A88 >*I4J4H4

M5G A;KL8L

8A88 >*I4J4H4

M5G A;KLL8A88 >*I4J4H4

*8AS

Circuit sym"ol for a relay

Relays

*hotogra#hs X Ra#i$ Electronics
http://www.rapidelectronics.co.uk/http://www.rapidelectronics.co.uk/


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A relay is an electrically o#erate$ sitch Current floing through the coil

of the relay creates a magnetic fiel$' hich attracts a le)er an$ changes the

sitch contacts The coil current can "e on or off so relays ha)e to sitch

#ositions an$ they are $ou"le thro


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#ro$uce "rief high )oltage s#i!es hen they are sitche$ off an$ this can

$estroy transistors an$ ICs in the circuit To #re)ent $amage you must

connect a#rotection $io$eacross the relay coil

The animate$ #icture shos a or!ing relay ith its coil an$ sitch

contacts ;ou can see a le)er on the left "eing attracte$ "y magnetism hen

the coil is sitche$ on This le)er mo)es the sitch contacts There is oneset of contacts


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hoosing a reay

;ou nee$ to consi$er se)eral features hen choosing a relay,

1% Physica siEe and in arrangementIf you are choosing a relay for an e1isting *CB you ill nee$ to

ensure that its $imensions an$ #in arrangement are suita"le ;ou

shoul$ fin$ this information in the su##liers catalogue

% oi otageThe relays coil )oltage rating an$ resistance must suit the circuit

#oering the relay coil Many relays ha)e a coil rate$ for a 7J

su##ly "ut 6 an$ JK relays are also rea$ily a)aila"le Some relays

o#erate #erfectly ell ith a su##ly )oltage hich is a little loer

than their rate$ )alue

6% oi resistanceThe circuit must "e a"le to su##ly the current re(uire$ "y the relay

coil ;ou can use Ohms lato calculate the current,

Relay coil current Q Su##ly )oltage

Coil resistance

6or eDame, A 7J su##ly relay ith a coil resistance of K99 #asses a

current of 9mA This is OH for a 666 timer IC


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Relays can sitch high )oltages' transistors cannot

Relays are a "etter choice for sitching large currents


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an$ in other lo3en$ analog recei)ers not re(uiring high tuning accuracy By

careful $esign an$ com#onent selection' an$ ith rugge$ mechanical

construction' 97 to 9997' or e)en "etter


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Ca#acitors are i$ely use$ in electronic circuits to "loc! the flo of $irect

currenthile alloing alternating currentto #ass' to filter out interference'

to smooth the out#ut of#oer su##lies' an$ for many other #ur#oses They

are use$ in resonant circuitsin ra$io fre(uency e(ui#ment to select #articular

fre(uenciesfrom a signal ith many fre(uencies

4heory o/ oeration

Main article, Ca#acitance

Charge se#aration in a #arallel3#late ca#acitor causes an internal electric

fiel$ A $ielectric

106168730 Larfereser Communicfrefefation 68

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Transcript of 106168730 Larfereser Communicfrefefation 68