Project 1 - Controlling a DC motor using PWM and monitoring its Running status
//AJAY JOSEPH SIR
//ANSWER :
#include <avr/io.h> // Pre-processor directive for I/O registers
#define F_CPU 16000000l // CPU frequency
#include "avr/interrupt.h" // User defined pre-processor directive for interrupts
#include <util/delay.h> // Pre-processor directive for delay functions
#define sw_dir (PIND & (1<<1)) // D1 pin as push button for direction control
#define sw_spd (PIND & (1<<2)) // D2 pin as push button for speed control
#define pw (PINC & (1<<3)) // C3 pin as push button for power ON/OFF
#define lcd_port PORTB // Port B pins used for LCD data
#define RS_high PORTD |= (1<<5) // D5 pin for Register select
#define RS_low PORTD &=~ (1<<5)
#define EN_high PORTD |= (1<<6) // D6 pin for Enable
#define EN_low PORTD &=~ (1<<6)
unsigned char i;
void lcd_cmd(char cmd) // For command register
{
lcd_port = (cmd & 0xF0); // 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) // For data register
{
lcd_port = (data & 0xF0); // For 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); // Return cursor to home
_delay_ms(5);
lcd_cmd(0x01); // Clear screen
_delay_ms(5);
lcd_cmd(0x0C); // Display ON, cursor OFF
_delay_ms(5);
lcd_cmd(0x06); // Increment cursor
_delay_ms(5);
lcd_cmd(0x80); // Cursor to begin at the 1st line
_delay_ms(5);
lcd_cmd(0x28); // 4 bit LCD mode
_delay_ms(5);
}
void cursor_position(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);
}
}
void lcd_out(char x, char y, char *str)
{
cursor_position(x, y);
while (*str)
{
lcd_data(*str);
str++;
}
}
int main(void)
{
DDRB = 0xFF; // Declaring pins B0 to B7 as outputs
DDRA |= ((1<<0)|(1<<1)); // Declaring pins A0 and A1 as outputs
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); // Internal pull up resistor for D2
PORTC |= (1<<3); // Internal pull up resistor for C3
i = 64; // As motor is running at with 25% duty cycle
TCCR0 = 0x61; // Non-inverting mode, PWM phase correct with no pre-scalars
GICR = (1<<INT0); // INT0 for interrupt
MCUCR = 0x02; // Interrupt is negative edge triggered
sei(); // Global interrupt
lcd_init();
while (1)
{
while (pw == 0) // Continues till the power push button gets released
{
if (sw_dir == 0) // if direction control push button gets released
{
PORTA = 0b00000001; // To rotate in clockwise direction
lcd_out(1,1, "Motor is running");
lcd_out(2,3, "clockwise");
}
else
{
PORTA = 0b00000010; // To rotate in anti clockwise direction
lcd_out(1,1, "Motor is running");
lcd_out(2,3, "anti clockwise");
}
OCR0 = i; // As i increases, the corresponding value is loaded into OCR0
}
PORTA = 0x00; // To stop the rotation
lcd_out(1,1, "Motor is OFF");
lcd_out(2,3, "CAUTION !!!");
}
}
ISR(INT0_vect) // Interrupt service routine
{
i = i + 20; // As i increases, the corresponding value is loaded into OCR0
}