Interface a LCD

Expt-1

1.      Title: Interface 16X2 LCD using 8 data pin

2.      Components required:

Sl. No.	Category	Item name/value	Quantity
1	IC	ATMEGA32	1
2		7805	1
3	Resistor	10K	1
4		330R	1
5	Capacitor	0.1uf	2
6		22pf	2
7		10uf, 24Volt	1
8	Crystal Oscillator	16MHz	1
9	LCD	16X2	1
10	Battery	9Volt	1

3.      Procedure & code:

#ifndef F_CPU

#define F_CPU 16000000UL

#endif

#include <avr/io.h>

#include <stdlib.h>

#include <util/delay.h>

#define E 5 //giving name “enable” to 5 pin of PORTD, since it Is connected to LCD enable pin

#define RS 6 //giving name “registerselection” to 6 pin of PORTD, since is connected to LCD RS pin

void send_a_command(unsigned char command);

void send_a_character(unsigned char character);

void send_a_string(char *string_of_characters);

int main()

{

int keypressed=0;

char buffer[10];

DDRD |= 1<<RS;//set PD6 as output pin

DDRD |= 1<<E;// set PD5 as output pin

send_a_command(0x01); //Clear Screen 0x01 = 00000001

_delay_ms(50);

send_a_command(0x38);//telling lcd we are using 8bit command /data mode

_delay_ms(50);

send_a_command(0b00001111);//LCD SCREEN ON and courser blinking

send_a_string("Working for 16X2");//displaying a string

send_a_command(0x80 + 0x40 +0);// moving courser to second line of LCD

_delay_ms(50);

keypressed=1234;

itoa(keypressed,buffer,10);

send_a_string(buffer);

send_a_command(0x80 +0);//move courser to first line.

_delay_ms(50);

send_a_command(0x01); //Clear Screen 0x01 = 00000001

return(0);          

}      

void send_a_command(unsigned char command)

{

PORTB = command;

PORTD &= ~ (1<<RS); //putting 0 in RS to tell lcd we are sending command

PORTD |= 1<<E; //telling lcd to receive command /data at the port

_delay_ms(50);

PORTD &= ~1<<E;//telling lcd we completed sending data

PORTB= 0;

}

void send_a_character(unsigned char character)

{

PORTB= character;

PORTD |= 1<<RS;//telling LCD we are sending data not commands

PORTD |= 1<<E;//telling LCD to start receiving command/data

_delay_ms(50);

PORTD &= ~1<<E;//telling lcd we completed sending data/command

PORTB = 0;

}

void send_a_string(char *string_of_characters)

{

while(*string_of_characters > 0)

{

send_a_character(*string_of_characters++);

}

}

4.      Circuit:

5.      Simulation:

https://youtu.be/24mU_K2Bn7o 

Expt-2

1.      Title: Interface 16X2 LCD using 4 data pin

2.      Components required:

Sl. No.	Category	Item name/value	Quantity
1	IC	ATMEGA32	1
2		7805	1
3	Resistor	10K	1
4		330R	1
5	Capacitor	0.1uf	2
6		22pf	2
7		10uf, 24Volt	1
8	Crystal Oscillator	16MHz	1
9	LCD	16X2	1
10	Battery	9Volt	1

3.      Procedure & code:

#ifndef F_CPU

#define F_CPU 16000000UL

#endif

#include <avr/io.h>

#include <util/delay.h>

#include "lcd.h"//download lcd.h and lcd.c

int main()

{

char buffer[10];

uint8_t rpm=30,d=0,duty;

lcd_init(LCD_DISP_ON_CURSOR);// initialize LCD

do

{

       if(rpm>90)

       {

              rpm=30;

       }

duty=rpm;

lcd_clrscr();// Clear screen

lcd_gotoxy(0,0);// goto 1st line 1st column

_delay_ms(50);

lcd_puts("RPM=");

itoa(rpm,buffer,10); //buffer loaded with RPM variable value

lcd_puts(buffer); //display RPM value

_delay_ms(50);

lcd_clrscr();// Clear screen

lcd_gotoxy(0,1);// goto 2nd line 1st column

lcd_puts(" Duty=");

d=((duty*100)/255); //percentage of rpm calculated as duty cycle

itoa(d,buffer,10); //buffer is loaded with duty cycle value

lcd_puts(buffer); //display duty cycle valu

lcd_puts("%");

_delay_ms(50);

rpm+=10;

} while (1);

return(0);          

}

4.      Circuit:

5.      Simulation:

https://youtu.be/7m1O719RFi4