Question

Design an interface for a ±24 V, 500 mA geared DC motor. The time constant of the motor is 10 ms. Include software to adjust the delivered power from 0 to 100%. Please write the code in C (Arduino AVR).

Answer 1

Assuming that

*We are using atmega328p microcontroller

* A motor driver which has a direction pin to change direction of motor and a pwm pin to change speed of the motor

*Direction pin is connected to PortB 0 pin and pwm pin is connected to portD 6 pin (OC0A)

* Using 8 bit mode of timer 0 for pwm

Code:

#include<avr/io.h>

#include<avr/interrupt.h>

#include<util/delay.h>

int main()

{

DDRB|== 1<0;// setting port B0(direction pin) as output

DDRD |= 1<<PD6;//setting pwm pin as output

PORTB |= 1<< PB0;

//Setting timer0 to fast pwm mode

TCCR0A |= 1<< COM0A1;

TCCR0A |= 1<< WGM01 | 1<<WGM00;

TCCR0A |= 1<<WGM02;

//Setting No prescaler

TCCR0A &= ~(1<<CS0|1<<CS01|1,<<CS02);

TIMSK |= 1<<OCIE0A; //enabling interrupt

while(1)

power(x); enter the value from 0 to 100%

}

void power(int p)

{

OCR0A = p *255/100;

}