[AVR] Help on LCD 16x2 interfacing for AVR microcontroller

[tauseefrehman]

Hi, i am trying to interface 16x2 lcd with avr microcontroller. i am new to c language and avr as well. although i am familiar with PIC and C++.

 

[milan.rajik]

Which Compiler and what clock frequency are you using ? If you are using Atmel Studio 6.x then Zip and post your complete project files.

 

[arun_190175]

read this code clock FQ 8MHz

#include<avr/io.h>
#include <stdio.h>
#include <avr/interrupt.h>
//#include <avr/signal.h>
//#include <avr/io.h>
#include <asm.h>
#include <util/delay.h>
#include <avr/pgmspace.h>
#include <avr/sfr_defs.h>
#define LCD_PORT PORTC
#define rombyte pgm_read_byte
#define EN SBIT(PORTC,6)
#define SW SBIT(PORTA,1)
#//define LCD_EN {LCD_PORT|=0x40;_delay_us(1);LCD_PORT&=~0x40;}
#define LCD_EN {EN=1;_delay_us(1);EN=0;}
unsigned int a;
unsigned char d;
#define RS 0x10
#define RW 0x20
int x;
char s[] PROGMEM={"ARUN KUMAR SHARMA"};
char f[] PROGMEM={"Abhay Sharma"};
char *p;
char g;
void busy()
{
  DDRC=0xF0;
  LCD_PORT=0x2F;
  //LCD_PORT|=0x20;
  do
  {
  LCD_PORT|=0x40;
  _delay_us(1);
  ASM_NOP();
  d=(PINC&0x0F)<<4;
  LCD_PORT&=~0x40;
  _delay_us(1);
  LCD_PORT|=0x40;
  _delay_us(1);
  //d|=(PINC&0x0F)<<4;
  LCD_PORT&=~0x40;
  }while(d&0x80);
  DDRC=0xFF;
  }


void LCD_WRITE_DATA(unsigned char data)
{
  LCD_PORT&=~RW;
  LCD_PORT|=RS;
  LCD_PORT=(LCD_PORT&0xF0)|(data>>4);
  LCD_EN;
  LCD_PORT=(LCD_PORT&0xF0)|(data&0x0F);
  LCD_EN;
 busy();
 // _delay_us(1000);
  }
 void LCD_WRITE_CMD(unsigned char data)
 {
  LCD_PORT&=~RW;
  LCD_PORT&=~RS;
  LCD_PORT=(LCD_PORT&0xF0)|(data>>4);
  LCD_EN;
  LCD_PORT=(LCD_PORT&0xF0)|(data&0x0F);
  LCD_EN;
  busy();
  //_delay_us(1000);
  }
 void init_LCD()
 {
   LCD_PORT=0x00;
   LCD_PORT|=0x02;
   LCD_EN;
   _delay_us(50);
   LCD_WRITE_CMD(0x28);
   LCD_WRITE_CMD(0x0F);
   LCD_WRITE_CMD(0x01);
   LCD_WRITE_CMD(0x02);
   } 
ISR(INT0_vect)
{
LCD_WRITE_CMD(0x01);
}
 
int main()
	{
	int i=0;
	DDRA=0xf1;
	PORTA=0x02;
	DDRC=0xFF;
	PORTC=0x00;
    DDRD=0b11111011;
    PORTD=0b00000100;
    MCUCR=(1<<ISC00)|(1<<ISC01);
    GICR=0b01000000;
    sei();
   init_LCD();
   p=&s[0];
   //g=rombyte(&s);
   while(rombyte(&*p))
   {
   LCD_WRITE_DATA(rombyte(&*p));
 
   i++;
   //p=pgm_read_byte(s[i]);
   p++;
    }
   
  // LCD_WRITE_DATA('S');
 while(1)
{

if(bit_is_set(PINA,1)/*PINA&0x02*/)
g=1;
if(g&&bit_is_clear(PINA,1)/*((PINA&0x02)==0)*/)
{
  g=0;
  p=f;
  //LCD_WRITE_CMD(0x01);
  LCD_WRITE_CMD(0xC0);
  while(rombyte(&*p))
   {
   LCD_WRITE_DATA(rombyte(&*p));
   p++;
    }
    }
}
//return 0 ;
}

i think this will help you

 

[tauseefrehman]

@milan.rajik i am using AVR Studio 5

- - - Updated - - -

@arun_190175 thank you for your response but understanding assembly language is very difficult for me at this moment. C will be better because its easy to understand. if you can help me with a C code that would be very helpful.

 

[arun_190175]

@milan.rajik i am using AVR Studio 5

- - - Updated - - -

@arun_190175 thank you for your response but understanding assembly language is very difficult for me at this moment. C will be better because its easy to understand. if you can help me with a C code that would be very helpful.

plz. Look the code. Also c winavrgcc. And. Avrstudio

 

[milan.rajik]

I don't have Atmel Studio 5. I have written code for Atmel Studio 6.2. I have included SBIT.H file. Include it in your projects. It is used for LCD defines. Try my code in AVR Studio. It might work.

https://www.edaboard.com/threads/287961/

Project attached. Proteus design attached. If display refresh seems slow then decrease delays used in LCD code.