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

#include <avr/io.h> // we are using i/o resisters of avr
#define F_CPU 16000000ul //define the crystal frequency
#include <avr/interrupt.h> // we are using external interrupt pin
#include <util/delay.h> //delay function purpose
#define sw_dir (PIND&(1<<1)) //d1 pin is declared as push button for direction control
#define sw_dspd (PIND&(1<<2)) //d2 pin is declared as push button for speed control
#define pw (PIND&(1<<3)) //d3 pin is declared as push button for power on/off.
#define lcd_port PORTC //portc pins are for LCD data
#define RS_high PORTD|=(1<<5) //d5 pin is used for resistor select(rs)
#define RS_low PORTD&=~(1<<5) //d5 pin is used for resistor select(rs)
#define EN_high PORTD|=(1<<6) //d6 pin is used for enable
#define EN_low PORTD&=~(1<<6) //d6 pin is used for enable
unsigned char i;
void lcd_cmd(char cmd) // command for LCD display
{
	lcd_port=(cmd&0xf0); //Masking 4 bits for 4 bit LCD mode//
	RS_low;
	EN_low;
	_delay_ms(1); //after 1ms disable LCD
	EN_high; // enable the LCD
	lcd_port=((cmd<<4)&(0xf0)); // LCD port
	RS_low;
	EN_low;
	_delay_ms(1); //after 1ms disable LCD
	EN_high; // enable the LCD
}
void lcd_data(char data) //send the data to LCD
{
	lcd_port=(data &0xf0); //masking 4 bits for bit LCD mode//
	RS_high; //access data register
	EN_low;
	_delay_ms(1);
	EN_high;
	lcd_port=((data<<4)&(0xf0)); //masking 4 bits for bit LCD mode//
	RS_high; //access data register
	EN_low;
	_delay_ms(1);
	EN_high;
}
void lcd_init()
{
	lcd_cmd(0x28);
	_delay_ms(5); //used for 4 bits LCD mode //
	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 //
}
void cursorpos(char x, char y)
{
	if ((x<1||x>2)||(y>16)||(y<1)) //condition will check the rows and 16 columns
	{
		x=1; //x=rows
		y=1; //y=columns
	}
	if (x==1)
	{
		lcd_cmd(0x7F+y); //{80-1=0B}for starting the first list hex decimal value(80){y we are the 7F+y means we need to start from that column
	}
	else //(x=2)
	{
		lcd_cmd(0xBF+y); //{0C-1=0B} for starting the second line, 2nd row
	}
}
void lcd_out(char x, char y, char *str) //here we are checking which position we want to print
{
	cursorpos(x,y);
	while (*str)
	{
		lcd_data(*str);
		str++;
	}
}
int adc_read(char channel) // we are configuring the adc value
{
	unsigned int a, result;
	ADMUX=channel; //here we are going to use which channel we need to select in mux here using 2 bit
	ADCSRA=0X80; // control and status register to enable the adc conversion enable the interrupt flag adc interrupt ADEN=1
	ADCH=0x00; // showing the value 0 or clearing the adc register
	ADCL=0x00; //showing the value 0
	ADCSRA|=(1<<6); // to start the conversion 6 bit adsc high
	while((ADCSRA&0x40)!=0); // when the conversion become zero means conversion of adc (0x40means interrupt pin)
	a=ADCL; //dummy data type a and a is stored the adcl register (ADC0-ADC7)
	result=ADCH; //store the high value (ADC8-ADC9)
	result=result<<8; //to get proper result or aligned value we need to do left shift
	result=result|a; //we are adding the ADCL+ADCH to get 16 bits
	return result;
}
int main(void)
{
	DDRB=0xFF; // declaring all 8 pins as output
	DDRA|=((1<<0)|(1<<1)); // declaring A0 and A1 as output
	DDRD&=~(1<<1); //declaring D1 pin as input
	DDRD&=~(1<<2); //declaring D2 pin as input
	DDRD|=(1<<5); //declaring D5 pin as output
	DDRD|=(1<<6); //declaring D6 pin as output
	DDRC&=~(1<<3); //declaring C3 pin as input
	PORTD|=(1<<2); //enabling internal pull up resistor for D2
	PORTC|=(1<<3); //enabling internal pull up resistor for D3
	i=64; // initializing i=64 because we are running the motor with 25%duty cycle
	TCCR0=0X61; // non inverting mode, PWM phase correct mode, no pre scalar
	GICR=(1<<INT0); // using into for interrupt
	MCUCR=0X02; // make interrupt negative edge triggered
	sei(); //enable global interrupt
	lcd_init(); // initialized LCD
	while (1)
	{
		while(pw==0) //continue till push button is released
		{
			if (sw_dir==0) // if the direction control push button is released
			{
				PORTA=0b00000001; //10 respective 1A 2A pins to rotate in clockwise direction
				lcd_out(1,1,"Motor ON-CLW"); // running clockwise direction
			}
			else
			{
				PORTA=0b00000010; //10 respective 1A 2A pins to rotate in anti-clockwise direction
				lcd_out(1,1,"Motor ON-ACL"); // running anti-clockwise direction
			}
			OCR0=i; // i increase in ISR, the corresponding value is to be loaded into OCR0
		}
		PORTA=0X00; //0 0 to respective 1A 2A pins to stop condition
		lcd_out(1,1,"Motor is_OFF");
	}
}
ISR(INT0_vect) // interrupt service routine
{
	i=i+20; //as i increases the duty cycle also increases “i” increases by 20 in each push and the corresponding value is to be loaded into OCR0 in while loop
}