Project 1 - Controlling a DC motor using PWM and monitoring its Running status
Project 1 - Controlling a DC motor using PWM and monitoring its Running status.
PROJECT
AIM:
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.
Goals:
- Implement a system on simulator for Controlling the DC motor using L293 motor driver.
- Displaying the running status of DC 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.
Deliverables of this project:
- Implement the system for controlling DC motor.
- Controlling the speed of the DC motor using PMW.
- Displaying the present running status of DC machine on LCD display.
DC Motor:
- A DC motor is defined as a class of electrical motors that convert direct current electrical energy into mechanical energy.
- When kept in a magnetic field, a current-carrying conductor gains torque and develops a tendency to move.
- Thus when electric fields and magnetic fields interact, a mechanical force arises.
- This is the principle on which the DC motors work.
L293 Motor Driver:
- L293d IC is known as a motor driver.
- It is a low voltage operating
device like other ICs. - The other ICs could have the same functions like L293d but they cannot provide the high voltage to the motor.
- L293d provides the continuous bidirectional Direct Current to the Motor.
- The Polarity of current can change at any
time without affecting the whole IC or any other device in the circuit. - L293d has an internal H-Bridge installed for two motors.
Code :
#include //we are using I/O registers of AVR
#define F_CPU 16000000L // define the crystal frequency
#include "avr/interrupt.h" // we are using external interrupt pin
#include // 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 (PINC & (1<<3)) // c3 is declared as push button for power ON/OFF
#define lcd_port PORTB //PORTB pins are for LCD data
#define RS_high PORTD |= (1<<5) // d5 pin is used for Register Select(RS)
#define RS_low PORTD &=~ (1<<5) // d5 pin is used for RS
#define EN_high PORTD |= (1<<6) // d6 pin is used for Enable
#define EN_low PORTD &=~ (1<<6) // d6 pin is used for En.
unsigned char i;
void lcd_cmd(char cmd) //command for lcd display
{
lcd_port = (cmd & 0xf0); //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); //4 bits for 4 bit lcd mode
RS_high; //access data register
EN_low;
_delay_ms(1);
EN_high;
lcd_port = ((data<<4) & (0xf0)); //4 bits for 4 bit lcd mode
RS_high; //access data register
EN_low;
_delay_ms(1);
EN_high;
}
void lcd_init()
{
lcd_cmd(0x28);// used for 4 bit lcd mode
_delay_ms(5);
lcd_cmd(0x02); // return 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 the display cursor
_delay_ms(5);
lcd_cmd(0x80); // force cursor to begin from 1st line
_delay_ms(5);
}
void cursorpos(char x,char y)
{
if((x<1 || x>2) || (y>16 || y<1 )) //condition will checks the 2 rows and 16 columns
{
x=1; //x= row
y=1; //y= column
}
if(x==1)
{
lcd_cmd(0x7F + y); //{ 80-1 = 7F} for starting the 1st line hex decimal value (80) {y we r using the 7F+y means we need to dtart from that column}
}
else //(x==2)
{
lcd_cmd(0xBF + y); //{0C-1 = 0B} for starting the 2nd 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 r configuring the adc value
{
unsigned int a, result;
ADMUX = channel; // here we r going to use which channel we need to select in mux here using 2 bit
ADCSRA = 0X80; //control & 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 (0x40 means interrupted pin )
a= ADCL; //dummy data type a and ais stored the ADCL register (ADC0-ADC7)
result = ADCH; // Store the high value (ADC8-ADC9)
result = result<<8; //to get proper result or alined value we need to do left shift
result = result | a ; // we r adding the ADCL + ADCH to get the 16 bits
return result;
}
int main(void)
{
DDRB = 0XFF; //Declaring all 8-pins as output.
DDRA |= ((1<<0)| (1<<1)); //Declaring A0 & A1 pins 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 prescalar.
GICR=(1<
MCUCR=0X02; //make interrupt negative edge triggered
sei(); //Enable global interrupt
lcd_init(); //Initialize lcd
while (1)
{
while(pw==0) //continue till the push button is released.
{
if(sw_dir == 0) //if the direction control push button is released.
{
PORTA = 0b00000001; // 1 0 to respective 1A 2A pins to rotate in clockwise direction.
lcd_out(1,1,"Motor ON- CL "); //Running clock wise direction
}
else
{
PORTA = 0b00000010; // 1 0 to respective 1A 2A pins to rotate in Anti-Clockwise direction.
lcd_out(1,1,"Motor ON- ACL");
}
OCR0 = i; //i increases in ISR, the corresponding value is to be loaded into OCR0.
}
PORTA = 0x00; // 0 0 to respective 1A 2A pins to Stop rotation.
lcd_out(1,1,"Motor is TURNOFF");
}
}
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//
}
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