Programming With AVR Microcontroller: Chapter 3

INTERFACE

1. LED BLINKING

Here we are blinking the led making it on and off for a certain duration using AT Mega 16

Circuit diagram:

 Program:

# define F_CPU 1000000UL

                   #define FOSC 16000000L       //here we define the clock frequency

                   #include <avr/io.h>

                   #include <util/delay.h>

                   int main(void)

                   {

                   DDRB = 0xFF;              //Makes PORTC as Output

                   While (1)                                 //infinite loop

                   {

                   PORTB = 0xFF;            //Turns ON All LEDs

                   _delay_ms(1000);                    //1 second delay

                             PORTB= 0x00;                       //Turns OFF All LEDs

                   _delay_ms(1000);                     //1 second delay

                   }

                   }

 2.LCD :

CIRCUIT DIAGRAM: 

 Program:

# define F_CPU 1000000UL

                   #include <avr/io.h>

                   #include <util/delay.h>

                   #include <string.h>

                   //#define LCD_PORT PORTB

                   #define RS PC0                                 //initialize register select as PC0 pin

                   #define EN PC1                                 //initialize enable pin as PC1

                   void CMD_WRT(unsigned char val)

                   {

         

                              PORTB=val;

                             PORTC = PORTC & (~(1<<RS));

                             _delay_ms(1);                          // here we provide a delay of 1 sec

                             ORTC = PORTC | ((1<<EN)); //make enable pin high

                              _delay_ms(1);

                              PORTC = PORTC & (~(1<<EN)); //make enable pin low

         

                   }

                   void DATA_WRT(unsigned char ch)

                   {

         

                             PORTB = ch;

                             PORTC = PORTC | ((1<<RS));//make register select pin high

                                _delay_ms(1);

                              PORTC = PORTC | ((1<<EN)); //make enable pin high

                              _delay_ms(1);

                              PORTC = PORTC & (~(1<<EN)); //make enable pin low

                   }

                   void LCD_WRT( char *string)

                   {

                              while(*string)

                             DATA_WRT(*string++);//will write the strings

                   }

                   int main(void)

                   {

                             //setting the display of the lcd

                              unsigned char CMD[]={0x38,0x01,0x0f,0x06,0x80},TEMP1,i;                                                   

                                       DDRB=0XFF;               //make PORTB as output        

                                DDRC = 0xFF;//(1<<RS)|(1<<EN);  //make PORTC as output

                                _delay_ms(10);                              //provide the delay of 10ms

                    for(i=0;i<5;i++)

                    {

                              TEMP1=CMD[i];                   //it will place the command in cmd array

                              CMD_WRT(TEMP1);  //it will write all the cmd that is in the cmd array

                    }

                      while(1)

                     {

         

                              CMD_WRT(0X01);     //clear display

                              CMD_WRT(0X80);     // blink the cursor in 1st row           

                              LCD_WRT("     --RDL--");//display RDL in lcd

                              CMD_WRT(0XC0);     //to use 2nd  row of lcd          

                              LCD_WRT("  LCD_DISPLAY"); //display LCD_DISPLAY in lcd

                  

                             _delay_ms(1000);                   //delay of 1sec

    }

                               return 0;

}

3.PULSE WIDTH MODULATION:

Program:

// program to change brightness of an LED

// demonstration of PWM

 

#include <avr/io.h>

#include <util/delay.h>

 

// initialize PWM

void pwm_init()

{

    // initialize timer0 in PWM mode

    TCCR0 |= (1<<WGM00)|(1<<COM01)|(1<<WGM01)|(1<<CS00);

 

    // make sure to make OC0 pin (pin PB3 for atmega32) as output pin

                         DDRB |= (1<<PB3);

}

 

void main()

{

              uint8_t brightness;

 

    // initialize timer0 in PWM mode

              pwm_init();

 

    // run forever

    while(1)

    {

        // increasing brightness

        for (brightness = 0; brightness < 255; ++brightness)

        {

            // set the brightness as duty cycle

            OCR0 = brightness;

 

            // delay so as to make the user "see" the change in brightness

            _delay_ms(10);

        }

 

        // decreasing brightness

        for (brightness = 255; brightness > 0; --brightness)

        {

            // set the brightness as duty cycle

            OCR0 = brightness;

 

            // delay so as to make the user "see" the change in brightness

            _delay_ms(10);

        }

 

    // repeat this forever

    }

}

 

4.ADC :

Program:

 # define F_CPU 1000000UL

#include <avr/io.h>

#include <util/delay.h>

#include <string.h>

//#include <iom16.h>

//#define LCD_PORT PORTB

#define RS PC0                  // connect register select pin to PC0

#define EN PC1                  // connect enable pin to PC1

 #define LTHRES 500        //setting the threshold valve   

 #define RTHRES 500

#include <stdlib.h>

void CMD_WRT(unsigned char val)

{

    

               PORTB=val;        // initializing PORTB as input and passing valve onto it

               PORTC = PORTC & (~(1<<RS));//make RS pin low

               _delay_ms(1);

               PORTC = PORTC | ((1<<EN));// make EN pin high

               _delay_ms(1);

               PORTC = PORTC & (~(1<<EN));// make EN pin low

    

}

void DATA_WRT(unsigned char ch)

{

    

               PORTB = ch; //initializing PORTB as input and passing CMD onto it

               PORTC = PORTC | ((1<<RS));        // make RS pin high

               _delay_ms(1);

               PORTC = PORTC | ((1<<EN));        //make EN pin high

               _delay_ms(1);

               PORTC = PORTC & (~(1<<EN));// make EN pin low

}

void LCD_WRT( char *string)

{

               while(*string)

               DATA_WRT(*string++);

}

 

 

  // initialize adc

  void adc_init()

  {

               // AREF = AVcc

                ADMUX = (1<<REFS0);       //initialize admux

      

       // ADC Enable and prescaler of 128

       // 16000000/128 = 125000

       ADCSRA = (1<<ADEN)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);

  }           //ADEN means ADC enabled

 

  // read adc value

  int adc_read(char ch)

  {

       // select the corresponding channel 0~7

       // ANDing with '7' will always keep the value

       // of 'ch' between 0 and 7

                ch &= 0b00000111;  // AND operation with 7

                ADMUX = (ADMUX & 0xF8)|ch;     // clears the bottom 3 bits                                                                                before ORing

      

       // start single conversion

       // write '1' to ADSC

                ADCSRA |= (1<<ADSC);

      

       // wait for conversion to complete

       // ADSC becomes '0' again

       // till then, run loop continuously

       while(ADCSRA & (1<<ADSC));

      

               return (ADC);

  }

 

int main(void)

{

                uint16_t adc_result0;//, adc_result1;

                     char int_buffer[10];       //creating array of 10

               unsigned char CMD[]={0x38,0x01,0x0f,0x06,0x80},TEMP1,i;

               DDRB=0XFF;//set port b as output

               DDRC = 0xFF;//(1<<RS)|(1<<EN);

               _delay_ms(10);

     for(i=0;i<5;i++)

     {

              TEMP1=CMD[i]; //for each one cycle each command will be placed in                                                                               that cmd array

              CMD_WRT(TEMP1);

     }

               adc_init();

     while(1)

     {

              //adc_result0 = adc_read(0);      // read adc value at PA0

              adc_result0 = adc_read(1);

             

              itoa(adc_result0, int_buffer,10);

             

              CMD_WRT(0X01);                 //clear display

              CMD_WRT(0X80);                 // cursor on first line

              LCD_WRT("     --RDL--");      //display  RDL

              CMD_WRT(0XC0);                //cursor on next line

              LCD_WRT(int_buffer);

             

              _delay_ms(1000);

              //TODO:: Please write your application code

     }

               return 0;

}

5.KEYPAD :

Block diagram:

Program:

#include<avr/io.h>

#include <avr/keypad.h>              // to initialize the keypad

#define F_CPU  1000000UL

#include <util/delay.h>                 //header to use delay function

#define   KEYPAD_PORT   PORTC     // connecting keypad to port c

#define   KEYPAD_PIN    PINC           //initializing pins for keypad

#define LCD_DATA_PORT  PORTB

#define LCD_CONT_PORT  PORTD

#define LCD_RS                PD0

#define LCD_RW               PD1

#define LCD_EN                PD2

#include <lcd.h>                                    //header to initialize LCD commands

    

void main(void)

{

               DDRB=0xFF;                //make PORTB as output

               DDRD=0X07;               //make PORTD pin 0, 1, 2 as output

               DDRB=0X0F;              

               PORTC=0xFF;              //make PORTC as output

               unsigned char keypad_valve;

               lcd_init();

while(1)

{

               lcd_command_write(0x08); //display off cursor off

               lcd_string_write("PRESS ANY KEY");

               lcd_command_write(0xc0);//2nd line display

               keypad_valve=read_keypad();

    

     if(keypad_valve!=0xFF)

     {

              lcd_number_write(keypad_valve,10);//if key is pressed corresponding                                                                                                 valve will be displayed

              lcd_data_write(' ');

     }

              else

                        ;

              _delay_ms(300);

     }

     }