Must #include <util/delay.h> . connect PORTA PIN0 to RS pin on LCD, connect PORTA PIN1 to RW pin on LCD, connect PORTA PIN2 to E pin on LCD, connect PORTA PINs 4,5,6,7 to Pins DB 4,5,6,7 on LCD , if you want to change to any port: edit .c file , in main function -> lcd_init(); in while(1) loop -> lcd_gotoxy(1,1); lcd_print("YOURSTRING");