Project 2 - Measuring distance of an object using ultrasonic sensor (HC-SR04)
// AJAY JOSEPH SIR
//ANSWER
#include <avr/io.h> // Pre-processor directive for I/O registers
#define F_CPU 16000000l // CPU frequency
#include <util/delay.h> // Pre-processor directive for delay functions
#include "avr/interrupt.h" // User defined pre-processor directive for interrupts
#define lcd_port PORTB // Port B pins used for LCD data
#define RS_high PORTD |= (1<<0) // D0 pin for Register select
#define RS_low PORTD &=~ (1<<0)
#define EN_high PORTD |= (1<<1) // D1 pin for Enable
#define EN_low PORTD &=~ (1<<1)
unsigned int tov=0, count, distance;
void lcd_cmd(unsigned char cmd) // For command register
{
lcd_port = cmd;
RS_low;
EN_low;
_delay_ms(1);
EN_high;
}
void lcd_data(unsigned char data) // For data register
{
lcd_port = data;
RS_high;
EN_low;
_delay_ms(1);
EN_high;
}
void lcd_init()
{
lcd_cmd(0x38); // 8 bit LCD mode
_delay_ms(5);
lcd_cmd(0x02); // Return cursor to home
_delay_ms(5);
lcd_cmd(0x01); // Clear screen
_delay_ms(5);
lcd_cmd(0x0C); // Display ON, cursor OFF
_delay_ms(5);
lcd_cmd(0x06); // Increment cursor
_delay_ms(5);
lcd_cmd(0x80); // Cursor to begin at the 1st line
_delay_ms(5);
lcd_cmd(0xC0);
_delay_ms(5); // Cursor to begin at the 2nd line
}
void cursor_position(char x, char y)
{
if ((x<1||x>2)||(y>16||y<1))
{
x = 1;
y = 1;
}
if (x == 1)
{
lcd_cmd(0x7F+y);
}
else
{
lcd_cmd(0xBF+y);
}
}
void lcd_out(char x, char y, char *str)
{
cursor_position(x, y);
while (*str)
{
lcd_data(*str);
str++;
}
}
void lcd_print(char row, char column, unsigned int value, int digits)
{
unsigned int temp, unit, tens, hundred, thousand, million;
unsigned char flag = 0;
if (row==0 || column==0)
{
cursor_position(1,1);
}
else
{
cursor_position(row, column);
}
if (digits==5 || flag==1)
{
million = value/10000+48;
lcd_data(million);
flag = 1;
}
if (digits==4 || flag==1)
{
temp = value/1000;
thousand = temp % 10+48;
lcd_data(thousand);
flag = 1;
}
if (digits==3 || flag==1)
{
temp = value/100;
hundred = temp % 10+48;
lcd_data(hundred);
flag = 1;
}
if (digits==2 || flag==1)
{
temp = value/10;
tens = temp % 10+48;
lcd_data(tens);
flag = 1;
}
if (digits==1 || flag==1)
{
unit = value % 10+48;
lcd_data(unit);
}
if (digits>5)
{
lcd_data('e');
}
}
int main(void)
{
DDRB = 0xFF; // Declaring pins B0 to B7 as outputs
DDRD |= (0<<6); // Declaring D6 pin as input from echo pin of sensor
DDRC |= (1<<0); // Port C0 as output
sei(); // Global interrupt
lcd_init();
TCCR1A = 0x00; // Normal mode
TIMSK |= (1<<2);
while (1)
{
PORTC |= (1<<0); // Trigger sensor
_delay_ms(15);
PORTC &=~ (1<<0);
TCCR1B = 0x41; // Enabling ICF
TCNT1 = 0;
TIFR = (1<<ICF1);
TIFR = (1<<TOV1);
tov = 0;
while ((TIFR & (1<<ICF1))==0); // Checking the timer overflow conditions
TCNT1 = 0;
TCCR1B = 0x01;
TIFR = (1<<ICF1);
TIFR = (1<<TOV1);
tov = 0;
while ((TIFR & (1<<ICF1))==0);
count = ICR1 + (65535*tov); // Calculating the count for the time
distance = (unsigned int)count/932.87; // Sensor datasheet formula
lcd_print(1,1,distance,4);
lcd_out(1,6, "cm");
}
}
ISR(TIMER1_OVF_vect)
{
tov++;
}
//NB : HEADER FILES IS MISSING WHILE UPLOADING