In this project, we will create a straightforward alarm clock using the timers of the ATmega32 microcontroller. The ATmega32A microcontroller features a 16-bit timer, which will be utilized for tracking seconds and constructing a digital clock.
Hardware components include the ATmega32 microcontroller, an 11.0592MHz crystal, two 22pF capacitors, a 5V power supply, AVR-ISP PROGRAMMER, a JHD_162ALCD (16×2 LCD), a 100uF capacitor connected to the power supply, four buttons, six 10KΩ resistors, four 100nF capacitors, two three-pin switches, a 2N2222 transistor, a buzzer, and a 200Ω resistor.
Software tools encompass Atmel Studio 6.1, ProgISP, or Flash Magic.
Here are the connections for the LCD:
1. Connect PIN1 (VSS) to ground.
2. Connect PIN2 (VDD or VCC) to +5v power.
3. Connect PIN3 (VEE) to ground (provides maximum contrast, ideal for beginners).
4. Connect PIN4 (RS or Register Selection) to PD6 of the microcontroller (uC).
5. Connect PIN5 (RW or Read/Write) to ground (sets the LCD in read mode, simplifying communication for the user).
6. Connect PIN6 (E or Enable) to PD5 of the microcontroller (uC).
7. Connect PIN7 (D0) to PB0 of the microcontroller (uC).
8. Connect PIN8 (D1) to PB1 of the microcontroller (uC).
9. Connect PIN9 (D2) to PB2 of the microcontroller (uC).
10. Connect PIN10 (D3) to PB3 of the microcontroller (uC).
11. Connect PIN11 (D4) to PB4 of the microcontroller (uC).
12. Connect PIN12 (D5) to PB5 of the microcontroller (uC).
13. Connect PIN13 (D6) to PB6 of the microcontroller (uC).
14. Connect PIN14 (D7) to PB7 of the microcontroller (uC).
The functioning of the alarm clock is detailed step by step in the following code: [Code description follows].
Code:
/* —- Code for Digital Clock with Alarm using AVR Microcontroller —— */
#include <avr/io.h>
#define F_CPU 11059200
#include <util/delay.h>
#include <stdlib.h>
#include <avr/interrupt.h>
#define enable 5
#define registerselection 6
void send_a_command(unsigned char command);
void send_a_character(unsigned char character);
void send_a_string(char *string_of_characters);
ISR(TIMER1_COMPA_vect);
static volatile int SEC =0;
static volatile int MIN =0;
static volatile int HOU =0;
int main(void)
{
DDRA = 0b11000000;
DDRB = 0xFF;
DDRD = 0xFF;
TCCR1B |=(1<<CS12)|(1<<CS10)|(1<<WGM12);
OCR1A=10800;
sei();
TIMSK |=(1<<OCIE1A);
char SHOWSEC [2];
char SHOWMIN [2];
char SHOWHOU [2];
int ALSEC = 0;
int ALMIN = 0;
int ALHOU = 0;
char SHOWALSEC [2];
char SHOWALMIN [2];
char SHOWALHOU [2];
send_a_command(0x01); //Clear Screen 0x01 = 00000001
_delay_ms(50);
send_a_command(0x38);
_delay_ms(50);
send_a_command(0b00001111);
_delay_ms(50);
while(1)
{
itoa(HOU/10,SHOWHOU,10);
send_a_string(SHOWHOU);
itoa(HOU%10,SHOWHOU,10);
send_a_string(SHOWHOU);
send_a_string (“:”);
send_a_command(0x80 + 3);
itoa(MIN/10,SHOWMIN,10);
send_a_string(SHOWMIN);
itoa(MIN%10,SHOWMIN,10);
send_a_string(SHOWMIN);
send_a_command(0x80 + 5);
send_a_string (“:”);
send_a_command(0x80 + 6);
itoa(SEC/10,SHOWSEC,10);
send_a_string(SHOWSEC);
itoa(SEC%10,SHOWSEC,10);
send_a_string(SHOWSEC);
if (bit_is_set(PINA,5))
{
send_a_string(” ALM:ON “);
if ((ALHOU==HOU)&(ALMIN==MIN)&(ALSEC==SEC))
{
PORTA|=(1<<PINB7);
}
}
if (bit_is_clear(PINA,5))
{
send_a_string(” ALM:OFF”);
PORTA&=~(1<<PINB7);
}
send_a_command(0x80 + 0x40 + 0);
send_a_string (“ALARM:”);
send_a_command(0x80 + 0x40 + 7);
itoa(ALHOU/10,SHOWALHOU,10);
send_a_string(SHOWALHOU);
itoa(ALHOU%10,SHOWALHOU,10);
send_a_string(SHOWALHOU);
send_a_command(0x80 + 0x40 +9);
send_a_string (“:”);
send_a_command(0x80 + 0x40 +10);
itoa(ALMIN/10,SHOWALMIN,10);
send_a_string(SHOWALMIN);
itoa(ALMIN%10,SHOWALMIN,10);
send_a_string(SHOWALMIN);
send_a_command(0x80 + 0x40+ 12);
send_a_string (“:”);
send_a_command(0x80 + 0x40+ 13);
itoa(ALSEC/10,SHOWALSEC,10);
send_a_string(SHOWALSEC);
itoa(ALSEC%10,SHOWALSEC,10);
send_a_string(SHOWALSEC);
send_a_command(0x80 + 0);
if (bit_is_set(PINA,4))
{
if (bit_is_clear(PINA,0))
{
if (MIN<60)
{
MIN++;
_delay_ms(220);
}
if (MIN==60)
{
if (HOU<24)
{
HOU++;
}
MIN=0;
_delay_ms(220);
}
}
if (bit_is_clear(PINA,1))
{
if (MIN>0)
{
MIN–;
_delay_ms(220);
}
}
if (bit_is_clear(PINA,2))
{
if (HOU<24)
{
HOU++;
}
_delay_ms(220);
if (HOU==24)
{
HOU=0;
}
}
if (bit_is_clear(PINA,3))
{
if (HOU>0)
{
HOU–;
_delay_ms(220);
}
}
}
if (bit_is_clear(PINA,4))
{
if (bit_is_clear(PINA,0))
{
if (ALMIN<60)
{
ALMIN++;
_delay_ms(220);
}
if (ALMIN==60)
{
if (ALHOU<24)
{
ALHOU++;
}
ALMIN=0;
_delay_ms(220);
}
}
if (bit_is_clear(PINA,1))
{
if (ALMIN>0)
{
ALMIN–;
_delay_ms(220);
}
}
if (bit_is_clear(PINA,2))
{
if (ALHOU<24)
{
ALHOU++;
}
_delay_ms(220);
if (ALHOU==24)
{
ALHOU=0;
}
}
if (bit_is_clear(PINA,3))
{
if (ALHOU>0)
{
ALHOU–;
_delay_ms(220);
}
}
}
}
}
ISR(TIMER1_COMPA_vect)
{
if (SEC<60)
{
SEC++;
}
if (SEC==60)
{
if (MIN<60)
{
MIN++;
}
SEC=0;
}
if (MIN==60)
{
if (HOU<24)
{
HOU++;
}
MIN=0;
}
if (HOU==24)
{
HOU=0;
}
}
void send_a_command(unsigned char command)
{
PORTB = command;
PORTD &= ~ (1<<registerselection);
PORTD |= 1<<enable;
_delay_ms(3);
PORTD &= ~1<<enable;
PORTB = 0xFF;
}
void send_a_character(unsigned char character)
{
PORTB = character;
PORTD |= 1<<registerselection;
PORTD |= 1<<enable;
_delay_ms(3);
PORTD &= ~1<<enable;
PORTB = 0xFF;
}
void send_a_string(char *string_of_characters)
{
while(*string_of_characters > 0)
{
send_a_character(*string_of_characters++);
}
}
Source: Alarm clock DPR
