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

Live Session(Preeti Mam)

AIM & OBJECTIVE :

Implement a system on the simulator for controlling a DC motor using L293 motor driver, monitor its status and print the running status of motor on the LCD Display.

Key Highlights of the Project:

• The DC motor can be controlled by using L293 motor driver.
• The speed of a DC motor can be controlled by varying its input voltage, for doing this is to use PWM (Pulse Width Modulation).
• L293D IC is a typical Motor Driver IC which allows the DC motor to drive on any direction.

About L293D Driver :

The L293D is designed to provide bidirectional drive currents of up to 600-mA at voltages from 4.5 V to 36 V.

The L293D is a 16-pin Motor Driver IC which can control a set of two DC motors simultaneously in any direction. The L293D is designed to provide bidirectional drive currents of up to 600 mA (per channel) at voltages from 4.5 V to 36 V .

Source Code :

#include <avr/io.h>                 // For I/o registers of AVR//
#include <util/delay.h>             // For the delay function //
#define F_CPU 16000000              // For the CPU frequency//
#include "avr/interrupt.h"          // For using external interrupt pin//


#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   (PINC&(1<<3))          // c3 is declared as push button for power on/off //

#define lcd_port PORTB              // port b pins dedicated for LCD data //

#define RS_high PORTD|=(1<<5)       // d5 pin is used for RS //
#define RS_low PORTD&=~(1<<5)
#define EN_high PORTD|=(1<<6)       // d6 pin is 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);         // Masking  4 bits for 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 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 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 line //
	lcd_cmd(0x28);_delay_ms(5);    // used for 4 bit lcd mode  //  
}

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);
	}
}

void lcd_out(char x, char y, char *str)
{
	 cursorpos(x,y);
	 while (*str)
	 {
		lcd_data(*str);
		str++;
	 }
}


int main()
{
	DDRB=0xFF;                             // Configuring all B pins as outputs//
	DDRA|=((1<<0)|(1<<1));                 // Configuring A pins as outputs//
	DDRD&=~(1<<1);                         // Configuring D1 pin as input//
	DDRD&=~(1<<2);                         // Configuring D2 pin as input//
	DDRD|=(1<<5);                          // Configuring D5 pin as output//
	DDRD|=(1<<6);                          // Configuring D6 pin as output//
	DDRC&=~(1<<3);                         // Configuring C3 pin as input//
	
	PORTD|=(1<<2);                          
	PORTC|=(1<<3);    
	                      
	i=64;                                  // 25% duty cycle as per the project requirement//
	TCCR0=0x61;                            
	GICR=(1<<INT0);                        // Interrupt Configuration
	MCUCR=0x02;                            // Making interrupt negative edge triggered//
	sei();                                 
	lcd_init();                            
	while(1)
	{
		while(pw==0)                       
		{
			if (sw_dir==0)                               // if the direction control push button is released//
			{
				PORTA=0b00000001;                             //For setting Pins of Port A in clockwise direction// 
				lcd_out(1,1,"Motor is Running");
				lcd_out(2,2,"Clockwise");
			}
			else
			{
				PORTA=0b00000010;                           //For setting Pins of Port A in Anticlockwise direction//
				lcd_out(1,1,"Motor is Running");
				lcd_out(2,3,"Anticlockwise");
			}
			OCR0=i;                                    // Max value of i to be loaded into OCR0  //
		}
		PORTA=0x00;                                    // Configuring pins of PORT A to stop rotating//
		lcd_out(1,1,"  Motor is OFF");
		lcd_out (2,2, "              ");
		
	}
}
ISR(INT0_vect)                                         //ISR function for incrementing the value of i by 20 every time the button is pushed
{
	i=i+20;                                 
}                                             

OutPut on Simulide :