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

Code

#include<avr/io.h>
#define F_CPU 16000000ul
#include "avr/interrupt.h"
#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); //Masking 4 bits for 4 bit LCD mode//
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)
{
lcd_port=(data &0xf0); //masking 4 bits for bit LCD mode//
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()
{
lcd_cmd(0x02);_delay_ms(5); //return the cursor to home//
lcd_cmd(0x01);_delay_ms(5); //clear screen //
lcd_cmd(0x0C);_delay_ms(5); //display ON cursor OFF//
lcd_cmd(0x06);_delay_ms(5); //increment cursor//
lcd_cmd(0x80);_delay_ms(5); //force cursor to begin 1st line //
lcd_cmd(0x28);_delay_ms(5); //used for 4 bits lcd mode //

}
void lcd_out(char x, char y, char *str)
{
cursorpos(x,y);
while (*str)
{
lcd_data(*str);
str++;
}
}
void cursorpos(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);
}
}
int main()
{
DDRB=0xFF;
DDRA|=((1<<0)|(1<<1));
DDRD&=~(1<<1);
DDRD&=~(1<<2);
DDRD|=(1<<5);
DDRD|=(1<<6);
DDRC&=~(1<<3);
PORTD|=(1<<2);
PORTC|=(1<<3);
i=64;
TCCR0=0X61;
GICR=(1<<INT0);
MCUCR=0X02;
sei();
lcd_init();
while (1)
{
while(pw==0)
{
if (sw_dir==0)
{
PORTA=0b00000001;
lcd_out(1,1,"Motor is Running");
lcd_out(2,3,"clockwise");
}
else
{
PORTA=0b00000010;
lcd_out(1,1,"Motor is Running");
lcd_out(2,3,"anticlockwise");
}
OCR0=i;
}
PORTA=0X00;
lcd_out(1,1," Motor is OFF");
lcd_out(2,3,"CAUTION !!!");
}
}
ISR(INT0_vect)
{
i=i+20;
}