Colony » Colony Scout » Colony Scout EE

#include <avr/io.h>

#include "motor.h"

#include <stdlib.h>

/*

motor controller

IN1: PD7

IN2: PD6

PWM: PB1

*/

int8_t motor_speed;

void motor_init(void)

{

  // WGM1 0b0101 (fast PWM, 8-bit)

  // COM1A 0b10 (clear OC1A on compare match, set on BOTTOM)

  // CS1 0b011 (64 prescaler)

  TCCR1A = _BV(WGM10) | _BV(COM1A1);

  TCCR1B = _BV(WGM12) | _BV(CS11) | _BV(CS10);

  OCR1AH = 0;

  // set IN1 (PD7), IN2 (PD6), and PWM (PB1) as output

  DDRD |= _BV(DDD7) | _BV(DDD6);

  DDRB |= _BV(DDB1);

  set_motor(0);

}

void set_motor(int8_t speed)

/* Speed must be between -127 and 127 */

{

  motor_speed = speed;

  OCR1AL = (uint8_t)abs(speed)*2;

  if(speed>0) //go forwards

  {

    PORTD |= (1<<PD7);

    PORTD = PORTD & ~(1<<PD6);

  }  

  if(speed<0) //go backwards

  {

    PORTD |= (1<<PD6);

    PORTD = PORTD & ~(1<<PD7);

  }

  if(speed==0) // turn motor off

  {

    PORTD = PORTD & ~(1<<PD6);

    PORTD = PORTD & ~(1<<PD7);

  }

}

int8_t get_motor()

{

  return motor_speed;

}