Below is the code for running 20x4 display LCD in 4 bit mode. You can copy the code and save it as a header file (.h) and then include the same in your main program.
Please don't forget to change the PINs according to your sketch.
Please leave a comment for any queries or feedback
/*
* lcd_lib.h
* Created By: Ramandeep Singh
* Created date: 11-Sep-2023
*/
#include <inttypes.h>
//Defines your PINS accordingly to your configuration
#define LCD_CONTROL_DDR DDRC
#define LCD_CONTROL_PORT PORTC
#define LCD_RS_PIN 6
#define LCD_RW_PIN 5
#define LCD_ENABLE_PIN 4
//
#define LCD_DATA1_DDR DDRC
#define LCD_DATA1_PORT PORTC
#define LCD_DATA1_PIN PINC
#define LCD_D4 0
#define LCD_D5 1
#define LCD_D6 2
#define LCD_D7 3
void lcd_cmd(uint8_t command) //used to write instruction to LCD
{
PORTC = command>>4;
PORTC &= (~(1<<LCD_RS_PIN)); //RS=0
PORTC &= (~(1<<LCD_RW_PIN)); //RW=0
PORTC |= (1<<LCD_ENABLE_PIN); //EN=1
_delay_ms(10); //10ms
PORTC &= (~(1<<LCD_ENABLE_PIN)); //EN=0
PORTC = (command & 0x0F);
PORTC &= (~(1<<LCD_RS_PIN)); //RS=0
PORTC &= (~(1<<LCD_RW_PIN)); //RW=0
PORTC |= (1<<LCD_ENABLE_PIN); //EN=1
_delay_ms(10); //10ms
PORTC &= (~(1<<LCD_ENABLE_PIN)); //EN=0
}
void lcd_data(uint8_t data) //for writing data to LCD
{
PORTC = data>>4 ;
PORTC |=(1<<LCD_RS_PIN); //RS=1
PORTC &=(~(1<<LCD_RW_PIN)); //RW=0
PORTC |=(1<<LCD_ENABLE_PIN); //EN=1
_delay_ms(10); //10ms
PORTC &=(~(1<<LCD_ENABLE_PIN)); //EN=0
PORTC = (data & 0x0F);
PORTC |=(1<<LCD_RS_PIN); //RS=1
PORTC &=(~(1<<LCD_RW_PIN)); //RW=0
PORTC |=(1<<LCD_ENABLE_PIN); //EN=1
_delay_ms(10); //10ms
PORTC &=(~(1<<LCD_ENABLE_PIN)); //EN=0
}
void LCD_print(char *str) /* Send string to LCD function */
{
int i;
for(i=0;str[i]!=0;i++) /* Send each char of string till the NULL */
{
lcd_data(str[i]);
}
}
void LCD_print_xy(uint8_t x, uint8_t y, char *str) {
uint8_t position = 0x80; // Starting address of the first line
if (y == 1) {
position = 0xC0; // Starting address of the second line
} else if (y == 2) {
position = 0x94; // Starting address of the third line
} else if (y == 3) {
position = 0xD4; // Starting address of the fourth line
}
position += x; // Add the x-coordinate to the position
lcd_cmd(position); // Send the command to set the cursor position
LCD_print(str);
}
void LCD_goto_XY(uint8_t x, uint8_t y) {
// Define the starting addresses for each line of a 20x4 LCD
static const uint8_t line_offsets[] = {0x00, 0x40, 0x14, 0x54};
// Ensure x and y are within bounds
if (x >= 20 || y >= 4) {
return; // Invalid coordinates
}
// Calculate the DDRAM address based on x and y
uint8_t position = line_offsets[y] + x;
// Set the cursor to the desired position
lcd_cmd(0x80 | position);
}
void LCD_init()
{
lcd_cmd(0x02); //Set cursor to home position
lcd_cmd(0x28); //4bit mode
lcd_cmd(0x06); //Entry Mode
lcd_cmd(0x0c); //display ON cursor OFF
lcd_cmd(0x01); //clear the display
lcd_cmd(0x80); //set cursor at line1
}
void LCD_clear()
{
lcd_cmd(0x01);
lcd_cmd (0x80);
}
//how to use:
//LCD_init();
//LCD_Print("My String");
//LCD_print_XY(0,0,"My String");
//LCD_goto_XY(16,3); LCD_print("My String");
//LCD_Clear();
