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ATMega16 AVR Microcontroller LCD Marquee

The ATMega16 LCD Marquee


In this ATMega16 AVR project we will be designing and implementing a Marquee with the aid of a Atmel AVR ATMega16 microcontroller and an alphanumeric LCD module.


Note: Although this AVR project was designed around the ATMega16 the project could have utilized another microcontroller such as an ATMega32, ATMega8515, etc.


ATMega16 LCD Marquee Operation & Hardware Description
Our LCD Marquee operates as follows. When the circuit is powered ON the text AVR TUTORIALS WELCOMES YOU will display on the screen. This text will blink then move to right, then to left, then to the right again. This sequence repeats.

The figure below gives the circuit diagram for the ATmega16 LCD Marquee system.

ATMega16 AVR Microcontroller LCD Marquee Circuit

Important Note: In order for the LCD Marquee unit to work correctly the internal oscillator of the ATMega16 AVR microcontroller must be enabled and set to 4MHz.

Software for the ATMega16 LCD Marquee Unit
Below is the AVR C implementation of the entire code for the ATMega16 based LCD marquee unit. The code was implemented and built using AVR Studio 5. Be reminded that the internal clock of the ATMega16 microcontroller should be enabled and programmed to operate at 4MHz for the AVR C code to operate correctly. A video of the LCD Marquee unit in operation is presented at the end of this page.

/*
 * Written in AVR Studio 5
 * Compiler: AVR GNU C Compiler (GCC)
 *
 * Created: 12/22/2011 4:39:50 PM
 * Author: AVR Tutorials
 * Website: www.AVR-Tutorials.com
 */ 
 
#define F_CPU	4000000UL
#include <avr/delay.h>
#include <avr/io.h>
 
/*LCD function declarations */
void LCD_send_command(unsigned char cmnd);
void LCD_send_data(unsigned char data);
void LCD_init();
void LCD_goto(unsigned char y, unsigned char x);
void LCD_print(char *string);
void LCD_blink();
void LCD_scroll(unsigned char direction);
 
#define LCD_DATA_PORT	PORTB
#define LCD_DATA_DDR	DDRB
#define LCD_DATA_PIN	PINB
 
#define LCD_CNTRL_PORT	PORTC
#define LCD_CNTRL_DDR	DDRC
#define LCD_CNTRL_PIN	PINC
 
#define LCD_RS_PIN		0
#define LCD_RW_PIN		1
#define LCD_ENABLE_PIN	2
 
int main(void)
{
	unsigned char i; 
 
    LCD_init();
	LCD_goto(1,2);
	LCD_print("AVR TUTORIALS");
	LCD_goto(2,3);
	LCD_print("WELCOMES YOU");
 
	while(1)
    {
        for(i=0;i<2;i++)
			LCD_blink();
 
		for(i=0;i<2;i++)
			LCD_scroll(0);
 
		for(i=0;i<4;i++)
			LCD_scroll(1);
 
		for(i=0;i<2;i++)
			LCD_scroll(0);
    }
}
 
/* This function sends a command 'cmnd' to the LCD module*/
void LCD_send_command(unsigned char cmnd)
{
	LCD_DATA_PORT = cmnd;
	LCD_CNTRL_PORT &= ~(1<<LCD_RW_PIN);
	LCD_CNTRL_PORT &= ~(1<<LCD_RS_PIN);
 
	LCD_CNTRL_PORT |= (1<<LCD_ENABLE_PIN);
	_delay_us(2);
	LCD_CNTRL_PORT &= ~(1<<LCD_ENABLE_PIN);
	_delay_us(100);
}
 
/* This function sends the data 'data' to the LCD module*/
void LCD_send_data(unsigned char data)
{
	LCD_DATA_PORT = data;
	LCD_CNTRL_PORT &= ~(1<<LCD_RW_PIN);
	LCD_CNTRL_PORT |= (1<<LCD_RS_PIN);
 
	LCD_CNTRL_PORT |= (1<<LCD_ENABLE_PIN);
	_delay_us(2);
	LCD_CNTRL_PORT &= ~(1<<LCD_ENABLE_PIN);
	_delay_us(100);
}
 
void LCD_init()
{
	LCD_CNTRL_DDR = 0xFF;
	LCD_CNTRL_PORT = 0x00;
	LCD_DATA_DDR = 0xFF;
	LCD_DATA_PORT = 0x00;
 
	_delay_ms(10);
	LCD_send_command(0x38);
	LCD_send_command(0x0C);
	LCD_send_command(0x01);
	_delay_ms(10);
	LCD_send_command(0x06);
}
 
/* This function moves the cursor the line y column x on the LCD module*/
void LCD_goto(unsigned char y, unsigned char x)
{
	unsigned char firstAddress[] = {0x80,0xC0,0x94,0xD4};
 
	LCD_send_command(firstAddress[y-1] + x-1);
	_delay_ms(10);	
}
 
void LCD_print(char *string)
{
	unsigned char i;
 
	while(string[i]!=0)
	{
		LCD_send_data(string[i]);
		i++;
	}
}
 
void LCD_blink()
{
	LCD_send_command(0x08);
	_delay_ms(250);
	LCD_send_command(0x0C);
	_delay_ms(250);
}
 
void LCD_scroll(unsigned char direction)
{
	if(direction == 0)
		LCD_send_command(0x18);
	else
		LCD_send_command(0x1C);
 
	_delay_ms(500);
}



Video of the ATMega16 LCD Marquee in Operation



AVR Tutorials hopes this AVR project on the ATMega16 LCD Marquee was benificial to you and looks forward to your continued visits for all your AVR microcontroller projects needs.