Project 1 - Controlling a DC motor using PWM and monitoring its Running status
1)
#include<avr/io.h> // we are using I/P register of Avr
#define F_CPU 16000000ul // define cpu frequency
#include "avr/interrupt.h" // we are using external interrupt pin
#include<util/delay.h> //delay funtion
#define sw_dir (PIND&(1<<1)) //d1 pin is declared as push button for direction control
#define sw_spd (PIND&(1<<2)) //d2 pin is declared as push button for speed control
#define pw (PIND&(1<<3)) //c3 declared push button for power ON/OFF
#define lcd_port PORTB //Portb pins are dedicated for lcd data
#define RS_high PORTD|=(1<<5) //d5 pin used forRS
#define RS_low PORTD&=~(1<<5)
#define EN_high PORTD|=(1<<6) //d6 pin used for EN
#define EN_low PORTD&=~(1<<6)
unsigned char i; // variable declared to increase the duty cycle in PWM.
void lcd_cmd(char cmd)
{
lcd_port=(cmd&0xf0); //4 bit for 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); //4 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 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 bit 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(void)
{
DDRB=0XFF; // declaring all B pins as output
DDRA|=((1<<0)|(1<<1)); // A0-A1 pins as output
DDRD&=~(1<<1); //D1 Pin input
DDRD&=~(1<<2); //D2 pin input
DDRD|=(1<<5); //D5 Pin output
DDRD|=(1<<6); //D6 pin output
DDRC&=~(1<<3); //C3 pin input
PORTD|=(1<<2); //enabling internal pull up resistor for D2
PORTC|=(1<<3); //enabling internal pull up resistor for C3
i=64; // initializing i= 64 baz we are running the motor with 25% duty cycle
TCCR0=0X61; // NON INVERTING MODE,PWM PHASE CORRECT MODE, NO PRESCALARS
GICR=(1<<INT0); //INT0 FOR INTERRUPT
MCUCR=0X02; //MAKE INTERRUPT NEGATIVE EDGE TRIGGERED
sei(); //enable global interrupt
lcd_init(); //initialize lcd
while (1)
{
while (pw==0) // continue till the power push button released
{
if (sw_dir==0) //if direction control push button released
{
PORTA =0b00000001; // 1 0 to respective 1A 2A pin to rotate in clockwise direction
lcd_out(1,1,"Motor is Running");
lcd_out(2,3,"Clockwise");
}
else
{
PORTA=0b000000010; //0 1 to respective 1A 2A pin to rotated in anti clockwise direction
lcd_out(1,1,"Motor is Running");
lcd_out(2,3,"anticlockwise");
}
OCR0=i; // i increase in ISR, corresponding value is to be loaded into OCR0
}
PORTA=0X00; // 0 0 RESPECTIVE 1A 2A PIN TO STOP ROTATION
lcd_out(1,1,"Motor is OFF");
lcd_out(2,3,"CAUTION !!!");
}
}
ISR(INT0_vect) // interrupt service routine
{
i=i+20; // i increase the duty cycle also increase . increase by 20 in each push
} // corresponding value is to be loaded into OCR0 while loop