Project 1 - Controlling a DC motor using PWM and monitoring its Running status

#include <avr/io.h>
#include "avr/interrupt.h"
#define F_CPU 16000000
#include <util/delay.h>
#define sw_dir (PIND&(1<<1))
#define sw_spd (PIND&(1<<2))
#define pw (PINC&(1<<3))
#define lcd_port PORTB
#define RS_high PORTD|=(1<<5)
#define RS_low PORTD&=~(1<<5)
#define EN_high PORTD|=(1<<6)
#define EN_low PORTD&=~(1<<6)
unsigned char i;
void lcd_cmd(char cmd)
{
lcd_port=(cmd&0xf0);
RS_low;
EN_low;
_delay_ms(1);
EN_high;
lcd_port=((cmd<<4)&(0xf0));
RS_low;
EN_low;
_delay_ms(1);
EN_high;
}

void lcd_data(char data){ // sending the data to lcd

lcd_port = (data & 0xf0);
RS_high;
EN_low;
_delay_ms(1);
EN_high;
lcd_port = ((data << 4)& (0xf0));
RS_high;
EN_low;
_delay_ms(1);
EN_high;
}
void lcd_init(){ // diff modes for lcd working
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);
}
void cursorpos(char x,char y){ // x for row y for columns
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){
cursorpos(x,y);
while(*str){
lcd_data(*str);
str++;
}
}
int main(void)
{
DDRB = 0xFF;
DDRA |= ((1<<0)|(1<<1));
DDRD &=~ (1<<1);
DDRD &=~ (1<<2);
DDRD |=(1<<6);
DDRC &=~ (1<<3);
PORTD |= (1<<2);
PORTC |= (1<<3);

i=64; //running the motor with 25% duty cycle.
TCCR0=0x61;
GICR=(1<<INT0);
MCUCR=0X02;
sei(); //Enable global interrupt
lcd_init();

while(1){
while(pw==0){ //continue till the push button is released.
if(sw_dir == 0){ //if the direction control push button is released.
PORTA = 0b00000001;
lcd_out(1,1,"motor ON - cl"); //Running clock wise direction
}
else {
PORTA = 0b00000010; // 1 0 to respective 1A 2A pins to rotate in Anti-Clockwise direction.
lcd_out(1,1,"motor ON - acl");

}

OCR0=i; // increases in ISR, the corresponding value is to be loaded into OCR0.

}
PORTA = 0X00;
lcd_out(1,1,"motor is turnoff");

}

}
ISR(INT0_vect){ //interrupt service routine
i=i+20;
}