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Connecting and interfacing with LCD in ATmega32

2 min read

in this program, we are going to connect an external LCD (Liquid-crystal Display) to our ATmega32 to display characters on the lcd. for our program we are using the Hd44780-2 LCD family. these type 16x2 LCD can interface in 2-modes; 4-bit mode and 8-bit mode. here we will be discussing about 8-bit mode variant.

sending commands to LCD

1.RS: → 0 selects command register
2.RW: → 0 select write operation
3.En: → make enable pin HIGH or LOW

sending data to LCD

1.RS: → 1 selects command register
2.RW: → 0 select write operation
3.En: → make enable pin HIGH or LOW

 
#include <avr/io.h>
#include <util/delay.h>
 
#define RS PC0
#define EN PC2
 
void command(unsigned char x) {
 PORTD = x;
 PORTC &= ~(1 << RS);
 PORTC |= (1 << EN);
 _delay_ms(1);
 PORTC &= ~(1 << EN);
}
 
void data(unsigned char x) {
 PORTD = x;
 PORTC |= (1 << RS);
 PORTC |= (1 << EN);
 _delay_ms(1);
 PORTC &= ~(1 << EN);
 _delay_ms(100);
}
 
int main(void) {
 DDRD = DDRC = 0xFF;
 command(0x38);
 command(0x0C);
 command(0x01);
 command(0x06);
 command(0x80);
 
 unsigned char i;
 
 unsigned char str[15]={"EMBEDDED SYSTEM"};
 for(i=0; str[i] != '\0'; i++) {
   data(str[i]);
 }
 return 0;
}

smaller experimental version

#include <avr/io.h>
#include <util/delay.h>
 
#define RS PC0
#define EN PC2
 
void w(uint8_t v, uint8_t rs) {
    PORTD = v;
    if(rs) PORTC |=  (1<<RS);
    else   PORTC &= ~(1<<RS);
    PORTC |=  (1<<EN);
    _delay_ms(1);
    PORTC &= ~(1<<EN);
    if(rs) _delay_ms(2);
}
 
int main(void) {
    DDRD = DDRC = 0xFF;
 
    w(0x38,0);
    w(0x0C,0);
    w(0x01,0);
    w(0x06,0);
 
    char s[]="EMBEDDED SYSTEM";
    for(uint8_t i=0; s[i]; i++)
        w(s[i],1);
 
    while(1);
}

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