Major Pro Report

8/19/2019 Major Pro Report

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INTRODUCTION

1.1 Background

The idea behind this project is to build a development board of wirelessdata transmission by using !"# microcontroller$ There are various type of

microcontroller$ The !"# microcontroller originally developed by Intel in #%!$

The purpose of choosing !"# microcontroller is that it can easily available in the

mar&et$ It is also simple and has enough features to meet with this project$

'ireless data transmissions are widely used in modern technology$ The

signal or data being transmitted wirelessly by mean of radio fre(uency$ The data

can be transmited in several ranges depending on the fre(uency of radio fre(uency

being used$

1.2 Objective:

The main objectives of this project are to)

#$ *uild hardware design for development of wireless data transmission

using microcontroller !"# interface with +CD screen and &eypad$

,$ 'rite an assembly language to program the system

1.3 Scope

These devise can operate over very long distances depending on the

range of radio fre(uency being used$ -or trial we have decided to use radio

fre(uency of ./. 012$ Notes that the greater the fre(uency the smaller the

distance$

This project consists of two parts3 hardware and software$ The hardware is

microcontroller based interfacing with +CD and switch while the software part will

writing by using an assembly language$


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REQUIREMENS

!"R#$"RE REQUIREMENS:

!"# microcontroller

T4./. 5 R4 ./.

#67, +CD DI89+:;

#,=

Decoder 1T>#,D

Deep 8witch

SO&$"RE REQUIREMENS:


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'IR'UI #ES'RI(ION

#ESI)NIN):

8ince the main intension of this project is to transfer a data from one location

and send it to specified location$ In order to fulfill this application there are few

steps that has been performed i$e$

#? Designing the power supply for the entire circuitry$

,? 8election of microcontroller that suits our application$/? 8election of R- modules that suits our application$

Complete studies of all the above points are useful to develop this project$

(O$ER SU((*+ SE'ION:

In>order to wor& with any components basic re(uirement is power

supply$ In this section re(uired voltage level is "@ DC$

That is

#? "@ DC power supply

Now the aim is to design the power supply section which converts ,/!@ :C

in to "@ DC$ 8ince ,/!@ :C is too high to reduce it to directly "@ DC3 therefore

we need a step>down transformer that reduces the line voltage to certain voltage

that will help us to convert it in to a "@ DC$ -or this application !>%@ transformers

is used3 since it is easily available in the mar&et$

The output of the transformer is %@ :CA it feed to rectifier that

converts :C to pulsating DC$


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:s we all &now that there are / &ind of rectifiers that is

#? half wave

,? -ull wave and

/? *ridge rectifier

1ere we use full wave rectifier3 because half wave rectifier has less

efficiency$The efficiency of full wave and bridge rectifier are the same$

(o,er -upp/ to a -ection-

8ince the output voltage of the rectifier is pulsating DC3 in order to convert it into

pure DC we use a high value B#!!!U-#"!!U-? of capacitor in parallel that acts as

a filter$ The most easy way to regulate this voltage is by using a !" voltage

Step

dow

n

T/F

Regulat

or Filter

Circuit

Full

Wave

Rectife

r


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regulator3 whose output voltage is constant "@ DC irrespective of any fluctuation

in line voltage$

'ircuit #iagra0 o (o,er Supp/:


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SE*E'ION O& MI'RO'ONRO**ER:

:s we &now that there so many types of micro controller families that are available

in the mar&et$

Those are

#? !"# -amily

,? :@R microcontroller -amily

/? 9IC microcontroller -amily

.? :R0 -amily

*asic !"# family is enough for our applicationA hence we are not

concentrating on higher end controller families$

In order to fulfill our application basic that is :T%C"# controller is

enough$ *ut still we selected :T%8", controller because of inbuilt I89 Bin system

programmer? option$

There are minimum si4 re(uirements for proper operation of microcontroller$Those are)

#? power supply section B"v?

,? pull>ups for ports Bit is must for 9ORT !?

/? Reset circuit

.? Crystal circuit

"? =:@99 pin is connected to @cc$

9ORT ! is open collector thatEs why we are using pull>up resistor

which ma&es 9ORT ! as an IO port$ Reset circuit is used to reset the

microcontroller$ Crystal circuit is used for the microcontroller for timing pluses$ In

this project we are not using e4ternal memory thatEs why =:@99 pin in the


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microcontroller is connected to @cc that indicates internal memory is used for this

application$

Bock #iagra0 o Ic41:

(in #iagra0 o Ic4


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(in de-cription o Ic41:


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S/0bo #ecription

9!$! to 9!$ 9ort !) 9ort ! is an >bit open drain bidirectional IO port$

The multiple4ed low>order address and data bus during

accesses to e4ternal code and data memory$ In this

application3 it uses strong internal pull>ups whentransitioning to F#Es$ 9ort ! also receives the code bytes

during the e4ternal host mode programming3 and outputs

the code bytes during the e4ternal host mode verification$

=4ternal pull>ups are re(uired during program verification

or as a general purpose IO port$

P1.0 to P1.7 9ort #) 9ort # is an >bit bidirectional IO port with internal

pull>ups$ The 9ort # pins are pulled high by the internal

pull>ups when F#Es are written to them and can be used asinputs in this state$ :s inputs3 9ort # pins that are e4ternally

pulled +O' will source current BII+? because of the

internal pull>ups$ 9#$"3 9#$63 9#$ have high current drive of

#6 m:$ 9ort # also receives the low>order address

bytes during the e4ternal host mode programming

9,$! to 9,$ 9ort ,) 9ort , is an >bit bidirectional IO port with internal

pull>ups$ 9ort , pins are pulled 1IG1 by the internal pull>

ups when F#Es are written to them and can be used as inputs

in this state$ :s inputs3 9ort , pins that are e4ternally pulled

+O' will source current BII+? because of

the internal pull>ups$ 9ort , sends th9e high>order address

byte during fetches from e4ternal program memory

9/$! to 9/$ 9ort /) 9ort / is an >bit bidirectional IO port with internal

pull>ups$ 9ort / pins are pulled 1IG1 by the internal pull>

ups when F#Es are written to them and can be used as inputs

in this state$ :s inputs3 9ort / pins that are e4ternally pulled

+O' will source current BII+? because of the internal pull>ups$ 9ort / also receives some control

signals and a partial of high>order address bits during the

e4ternal host mode programming and verification$

98=N 9rogram 8tore =nable) 98=N is the read strobe for e4ternal

program memory$ 'hen the device is e4ecuting from


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internal program memory3 98=N is inactive B1IG1?$

'hen the device is e4ecuting code from e4ternal program

memory3 98=N is activated twice each machine

cycle3e4cept that two 98=N activations are s&ipped during

each access to e4ternal data memory$ : forced 1IG1>to>+O' input transition on the 98=N pin while the R8T input

is continualy held 1IG1 for more than #! machine cycles

will cause the device to enter e4ternal host mode

programming$

R8T Reset) 'hile the oscillator is running3 a 1IG1 logic state

on this pin for two machine cycles will reset the device$ If

the 98=N pin is driven by a 1IG1>to>+O' input transition

while the R8T input pin is held 1IG13 the device will enterthe e4ternal host mode3 otherwise the device will enter the

normal operation mode$

=: =4ternal :ccess =nable) =: must be connected to @88 in

order to enable the device to fetch code from the e4ternal

program memory$ =: must be strapped to @DD for internal

program e4ecution$ The =: pin can tolerate a high voltage

of #, @$

:+=9ROG :ddress +atch =nable) :+= is the output signal for latching

the low byte of the address during an access to e4ternal

memory$ This pin is also the programming pulse input

B9ROG? for flash programming$ Normally the :+=

is emitted at a constant rate of #H6 the crystal fre(uency and

can be used for e4ternal timing and cloc&ing$ One :+=

pulse is s&ipped during each access to e4ternal data

memory$ 1owever3 if :O is set to F#E3 :+= is disabled$

7T:+# Crystal #) Input to the inverting oscillator amplifier and

input to the internal cloc& generator circuits$7T:+, Crystal ,) Output from the inverting oscillator amplifier$

@DD 9ower supply

@88 Ground

SELECTION OF RF:


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The aim o this project is to transmit data rom one place to

another, so wireless communication is required to ulfll our

application There are di!erent wirelesses communications

e"ist For this application we preer #asic RF module

Fig (a).RF Transmitter

Fig (b).RF Receiver

CIRCUIT OPERATION


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'OM(ONENS USE# :

1. !12# #E'O#ER

1T#,D IC comes from 1olte& Company$ 1T#,D is a decoder integrated circuit

that belongs to ,#, series of decoders$ This series of decoders are mainly used for


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remote control system applications3 li&e burglar alarm3 car door controller3 security

system etc$ It is mainly provided to interface R- and infrared circuits$ They are

paired with ,#, series of encoders$ The choosen pair of encoderdecoder should

have same number of addresses and data format$ In simple terms3 1T#,D converts

the serial input into parallel outputs$ It decodes the serial addresses and datareceived by3 say3 an R- receiver3 into parallel data and sends them to output data

pins$ The serial input data is compared with the local addresses three times

continuously$ The input data code is decoded when no error or unmatched codes

are found$ : valid transmission in indicated by a high signal at @T pin$ 1T#,D is

capable of decoding #, bits3 of which are address bits and . are data bits$ The

data on . bit latch type output pins remain unchanged untill new is received$

(in #iagra0


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