Jay Pandit

12MT06PED016

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Contents Keil

Proteus

Some basic techniques for C programming

Application 1

Application 2

Application 3

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How to start 1st Keil project..

Install keil software from the installation file.

Start keil program from start menu or from desktop shortcut.

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Select New μvision Project

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Do not change the file type!!!

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Atmel

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AT89C51

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Create New File

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Save file as .c or .asm

Right Click and select Add files to group

Source 1

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Click Add

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Select Options for Target

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Any one want to try this ?????

Before we start programming

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Data Types in Embedded C

Data Type Size in Bits Data range

Unsigned char 8-bit 0 to 255

(Signed) char 8-bit -128 to 127

Unsigned int 16-bit 0 to 65535

(Signed) int 16-bit -32768 to 32767

sbit 1-bit SFR bit Addressable only

Bit 1-bit RAM bit-addressableonly

sfr 8-bit RAM addresses

Before we start programming

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Interrupt numbers in C

Interrupt Name Number used by 8051

External interrupt 0 INT0 0

Timer interrupt 0 TF0 1

External interrupt 1 INT1 2

Timer interrupt 1 TF1 3

Serial communication RI+TI 4

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For loopchar i;for(i=0;i<10;i++){

}

Write your code here

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Infinite loopwhile(1){

}

Write your code here

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Assembly instructions in C code #pragma ASM

#pragma END ASM

Write your code here

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Functionsint addition(int,int);void main(){

int i,j,k;i = 10;j = 10;k = addition(i,j);

}

int addition(int a, int b){

int cc = a + b;return(c);

}

Provide gate signals.

Variation in duty ratio of gate signals.

Variation in frequency of gate signals.

Sensing of voltage.

Sensing of current.

Sensing of speed.

What are your expectations from a microcontroller????

Requirements from microcontroller

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DC –DC Converter open loop Gate signals are in the form of square wave

There may be change in duty ratio of gate

signals.

There may be change in frequency of gate

signals.

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Program 1

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Problem statement :

Write a program to generate a square wave on pin 1 of port 2Frequency of square wave = 1kHzDuty ratio = 50%

Delay calculation :

Assume that XTAL = 11.0592 MHz . n = 500 μ /1.085μ = 460 Count = 65536 – n = 65076 Count in hex = FE34H Load TH = FEH and TL =34H

Program

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#include <reg51.h>sbit SW = P2^1;

void delay();

void main(){

TMOD = 0x01;while(1){

SW = 1;delay();SW = 0;delay();

}}

void delay(){

TH0 = 0xFE;TL0 = 0x34;TR0 = 1;while(!TF0);TR0 = 0;TF0 = 0;

}

Lets go to Keil for trying this program

Program 2

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Problem statement :Write a program to generate a square wave on pin 1 of port 2Frequency of square wave = 10kHzDuty ratio = variable.

Time period of wave = 100 μsec

We would be requiring two delays One for on time. Another for off time.

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Program#include <reg51.h>

sbit SW P2^1

void delay1();void delay2();

extern char count;void main(){

count = 0;EA = 1;EX0 = 1;EX1 = 1;IT0 = 1;IT1 = 1;TMOD = 0x01;

while(1){

SW = 1;delay1();SW = 0;delay2;

}}void delay1(){

TH0 = 0xFF;TL0 = 210+count;TR0 = 1;while(!TF0);TR0=0;TF0=0;

}

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Program cont.void delay2(){

TH0 = 0xFF;TL0 = 210-count;TR0 = 1;while(!TF0);TR0=0;TF0=0;

}void external0() interrupt 0{

count++;}

void external0() interrupt 1{

count--;}

Lets try to simulate this program

Program 3

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Problem statement :Write a program to generate a square wave on pin 1 of port 2Frequency of square wave = Variable.Duty ratio = 50%.

Time period of wave = variable

Hence,Count to be loaded in timer register = variable

Requirements to be satisfied by the program User should be able to vary the frequency.Frequency raise and lower commands are given by user.There should be upper and lower limit on frequency.

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How to satisfy these requirements using program????

• Delay can be created using - Timers

Solutions

• User interface can be created by using - Interrupts

• Limits can be put by using conditions like if-else

Program

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#include <reg51.h>

sbit SW = P2^1

void delay();

extern unsigned char count;void main(){

count = 0x01;EA = 1;EX0 = 1;IT0 = 1;IT1 = 1;TMOD = 0x01;

while(1){

SW = 1;delay();SW = 0;delay();

}}

void delay(){

TH0 = 0xFF;TL0 = count;while(!TF0);TR0 = 0;TF0 = 0;

}

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Program cont.void external0() interrupt 0{

if(count < 0xFA)count++;

elsecount = 0xFA;

}

void external0() interrupt 1{

if(count > 0x01)count--;

elsecount = 0x01;

}

Provide gate signals.

Variation in duty ratio of gate signals.

Variation in frequency of gate signals.

Sensing of voltage.

Sensing of current.

Sensing of speed.

Requirements from microcontroller

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How to sense analog signals like voltage, current???

Solution : Analog to digital converters.

Limitations of ADC:It can read only positive voltage.It can read voltage between 0-5V.ADC can not read current.

Solution :Current sensor produces proportional voltage output for input current.Voltage divider is used for sensing high voltage.Tachometer generates voltage signal proportional to speedSignal conditioning is required to sense negative voltages.

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ADC0804 chip

ADC0804 is an 8-bit parallel ADC.

It works with +5V voltage supply.

It has a resolution of 8 bits.

Conversion time depends on clocking signals applied to

CLK IN pin, but it cannot be faster than 110μs.

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Pin details of ADC0804CS Chip select is an active low input used to activate chip.

RD Used to read the converted data. Signal should be active low

WR Start of conversion. Signal should be active low.

CLK IN Input for clock

INTR End of conversion

Vcc Supply voltage +5V

Vref/2 Kept open for reading voltage in range 0-5V.

D0-D7 Digital data output pins.

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Relation of Vref/2 and Vin range

Vref/2(V) Vin(V) Step size(mV)

Not connected 0 to 5 19.53

2.0 0 to 4 15.62

1.5 0 to 3 11.71

1.28 0 to 2.56 10

Step size = Vin(max)/256

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How to calculate output

Dout = Digital data output in decimal.

Vin = analog input voltage.

Dout = Vin/step size

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Program 4

Problem statement: Using the ADC and current sensor read the value of current flowing in the branch of circuit, and display it on port3

Solution:

Current sensor ACS712ELCTR-20A-T is used.

Current sensor can read current up to +/- 20A.

Gain of current sensor (refer data sheet).

ADC0804 is used.

Internal clock is used.

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Program

#include<reg51.h>

sbit READ = P2^5;sbit WRITE = P2^6;sbit INTR = P2^7;

void main(){

unsigned char value;P1 = 0xFF;INTR = 1;READ = 1;WRITE = 1;

while(1){

WRITE = 0;WRITE = 1;while(INTR);READ = 0;value = P1;READ = 1;P3 = value;

}}

Lets simulate this code.

Provide gate signals.

Variation in duty ratio of gate signals.

Variation in frequency of gate signals.

Sensing of voltage.

Sensing of current.

Sensing of speed.

Our achievements

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