Project 2 - Measuring distance of an object using ultrasonic sensor (HC-SR04)

#include <avr/io.h>
#define F_CPU 16000000L
#include <util/delay.h>
#include "avr/iterrupt.h"

#define lcdport PORTB

#define rs_high PORTD |=(1<<0);
#define rs_low PORTD &=~(1<<0);

#define en_high PORTD |=(1<<1);
#define en_low PORD &=~(1<<1);

unsigned int tov=0,count,distance;
void lcd_command(unsigned char cmd);
void lcd_data(unsigned char data);
void init();
void cursorpos(char x,char y)
void lcd_out(char x,char y,char *str)
void lcd_print(char row,char column,unsigned int value,int digits);

int main(void)
{
DDRB=0xff;
DDRD |=(1<<6);
DDRC |=(1<<0);
sei();
lcd_init();
TCCR1A=0x00;
TIMSK |=(1<<2);
while(1)
{
PORTC |=(1<<0); //trigger sensor
_delay_us(10);
PORTC &=~(1<<0);
TCCR1B=0x41;
TCNT1=0;
TIFR=(1<<ICF1);
TIFR=(1<<TOV1);
tov=0;
while((TIFR &(1<<ICF1))==0);
TCNT1=0;
TCCR1B=0x01;
TIFR=(1<<ICF1);
TIFR=(1<<TOV1);
tov=0;
while((TIFR&(1<<ICF1))==0);
count = ICR1 + (65535 * tov);
distance = (unsigned int)count /932.87;
lcd_print(1,1,distance,4);
lcd_out(1,6,"cm");
}
}
ISR(TIMER1_OVF_vect)
{
tov++;
}
void lcd_cmd(unsigned char cmd)
{
lcdport=cmd;
rs_low;
en_low;
_delay_ms(1);
en_high;
}
void lcd_data(unsigned char data)
{
lcdport=data;
rs_high;
en_low;
_delay_ms(1);
en_high;
}

void lcd_init()
{
lcd_cmd(0x38);_delay_ms(5);
lcd_cmd(0x02);_delay_ms(5);
lcd_cmd(0x01);_delay_ms(5);
lcd_cmd(0x0c);_delay_ms(5);
lcd_cmd(0x06);_delay_ms(5);
lcd_cmd(0x80);_delay_ms(5);
lcd_cmd(0xc0);_delay_ms(5);
}
void cursorpos(char x,char y)
{
if((x<1||x>2)||(y<1||y>16))
{
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)
{
cursorpos(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)
{
cursorpos(1,1);
}
else
{
cursorpos(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');
}
}