Overview of the Project: 

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.

Expected Outcomes: 

• Implement a system on simulator to control a DC motor using PMW
• Monitoring the running status of the DC motor using L293 motor driver which allows the DC motor to drive on any direction.
• Running status i.e. on which direction the DC motor is running is to be displayed on the LCD screen.

 

Configuring Timer0 for PWM generation

It is simple to configure PWM mode in Timer. We just need to set some bits in the TCCR0 register.

TCCR0: Timer Counter Control Register 0

 

Bit 7- FOC0: Force compare match

Write only bit, which can be used while generating a wave. Writing 1 to this bit will force the wave generator to act as if a compare match has occurred.

Bit 6, 3 - WGM00, WGM01: Waveform Generation Mode

 

WGM00	WGM01	Timer0 mode selection bit
0	0	Normal
0	1	CTC (Clear timer on Compare Match)
1	0	PWM, Phase correct
1	1	Fast PWM

 

Bit 5:4 - COM01:00:

1. When WGM00: WGM01= 11 i.e. Fast PWM. Compare Output Mode

waveform generator on OC0 pin

 

COM01	COM00	Mode Name	Description
0	0	Disconnected	The normal port operation, OC0 disconnected
0	1	Reserved	Reserved
1	0	Non-inverted	Clear OC0 on compare match, set OC0 at TOP
1	1	Inverted PWM	Set OC0 on compare match, clear OC0 at TOP

 

         2. When WGM00: WGM01= 10 i.e. Phase correct PWM. Compare Output Mode

waveform generator on OC0 pin

 

COM01	COM00	Description
0	0	The normal port operation, OC0 disconnected
0	1	Reserved
1	0	Clear OC0 on compare match when up-counting, set OC0 on compare match when down-counting
1	1	Set OC0 on compare match when up-counting, Clear OC0 on compare match when down-counting

 

           Bit 2:0 - CS02:CS00: Clock Source Select

These bits are used to select a clock source. When CS02: CS00 = 000, then timer is stopped. As it gets a value between 001 to 101, it gets a clock source and starts as the timer.

 

CS02	CS01	CS00	Description
0	0	0	No clock source (Timer / Counter stopped)
0	0	1	clk (no pre-scaling)
0	1	0	clk / 8
0	1	1	clk / 64
1	0	0	clk / 256
1	0	1	clk / 1024
1	1	0	External clock source on T0 pin. clock on falling edge
1	1	1	External clock source on T0 pin. clock on rising edge.

 

Fast PWM mode 

To set Fast PWM mode, we have to set WGM00: 01= 11. To generate a PWM waveform on the OC0 pin, we need to set COM01:00= 10 or 11.

COM01:00= 10 will generate Noninverting PWM output waveform and COM01:00= 11 will generate Inverting PWM output waveform. 

 

Setting Duty cycle: we have to load value in the OCR0 register to set the duty cycle.

255 value for 100% duty cycle and 0 for 0% duty cycle. Accordingly, if we load value 127 in OCR0, the Duty cycle will be 50%.

 

 

 

 

Code:

/*
* pwmmotorp1.c
*
* Created: 10-04-2022 16:52:25
* Author : SS
*/

#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 xss=removed>#define sw_dspd (PIND & (1<<2 xss=removed>#define pw (PINC & (1<<3>

#define lcd_port PORTB //PORTB pins are for LCD data
#define RS_high PORTD |= (1<<5 xss=removed>#define RS_low PORTD &=~ (1<<5 xss=removed>#define EN_high PORTD |= (1<<6 xss=removed>#define EN_low PORTD &=~ (1<<6 xss=removed>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 xss=removed>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 xss=removed>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>2) || (y>16 || y<1 xss=removed>{
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 xss=removed>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 xss=removed>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 xss=removed>DDRD &=~ (1<<1 xss=removed>DDRD &=~ (1<<2 xss=removed>DDRD |= (1<<5 xss=removed>DDRD |= (1<<6 xss=removed>DDRC &=~ (1<<3 xss=removed>PORTD |= (1<<2 xss=removed>PORTC |= (1<<3 xss=removed>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
/* Replace with your application code */
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//
}

Motor in CLOCKWISE DIRECTION AT25 % DUTY CYCLE

Motor in ANTICLOCKWISE DIRECTION

Dutycycle =60

Duty cycle above 70%