Motors

Related to: [HW] Motor Module

This library contains functions to control different HomeLab motors. There are functions for DC, stepper and servo motors.

• prescale
  PWM clock prescaler enumration data type. It determines the division factor of system clock. It is recommended to use the first two division factors. Options:
  • TIMER2_NO_PRESCALE - Division factor not used.
  • TIMER2_PRESCALE_8 - Division factor 8.
  • TIMER2_PRESCALE_64 - Division factor 64.
  • TIMER2_PRESCALE_256 - Division factor 256.
  • TIMER2_PRESCALE_1024 - Division factor 1024.

• void dcmotor_init(unsigned char index)
  

Initializes one of the DC motor controllers. Parameters:

• index - Index of motor controller. 0 to 3.

• void dcmotor_drive(unsigned char index, signed char direction)
  

Drives one of the DC motor controllers. Parameters:

• index - Index of motor controller. 0 to 3.
• direction - Motor polarity. -1, 0 or +1. In case of 0 motor is stopped, otherwise it turns in given direction.

• void dcmotor_drive_pwm_init(unsigned char index, timer2_prescale prescaler)
  Initializes one of the DC motor controllers for speed control. In addition, you can set the appropriate prescaler, depending on the frequency of the PWM's you need. Parameters:
  • index - Index of motor controller. 0 to 3.
  • prescaler - Clock prescaler selection. Interruptions can occur very quickly upset the program of work. For example, when the UH sensor is used, it is necessary to set the prescaler TIMER2_PRESCALE_8.

• void dcmotor_drive_pwm(unsigned char index, signed char direction, unsigned char speed)
  

Drives one of the DC motor controllers. Motor rotates in a predetermined direction and speed. Parameters:

• index - Index of motor controller. 0 to 3.
• direction - Motor polarity. -1 or +1.
• speed - Motor speed. 0 to 255. 0 the engine is stopped and the 255 is the maximum possible speed.

• void unipolar_init(unsigned char index)
  

Initializes one of the unipolar stepper motor controllers. Parameters:

• index - Index of motor controller. 0 or 1.

• void unipolar_halfstep(unsigned char index, signed char direction, unsigned short num_steps, unsigned char speed)
  

Unipolar stepper motor half-stepping command. Functions is blocking as it is fulfilled as long as steps are done. Parameters:

• index - Index of motor controller. 0 or 1.
• direction - Directions of rotation. -1 or +1.
• num_steps - Count of half-steps.
• speed - Time of a single step in milliseconds.

• void bipolar_init(void)
  

Initializes bipolar stepper motor controller.

• void bipolar_halfstep(signed char direction, unsigned short num_steps, unsigned char speed)
  

Bipolar stepper motor half-stepping command. Functions is blocking as it is fulfilled as long as steps are done. Parameters:

• direction - Directions of rotation. -1 or +1.
• num_steps - Count of half-steps.
• speed - Time of a single step in milliseconds.

• void servomotor_init(unsigned char index)
  

Initializes one of a servo motor PWM signal generations units in ATmega128 timer 1. PWM signal is 50 hz with high period of 1.5 ms ± 0.5 ms. Parameters:

• index - Index of servo motor. 0 or 1.

• void servomotor_position(unsigned char index, signed short position)
  

Servo motor pulse width control command. If positioning servo motor is driven, its position is altered, if rotating one, its rotation speed is altered. Parameters:

• index - Index of servo motor. 0 or 1.
• position - Position or rotation speed. -100 to +100. 0 corresponds to stop.

The following program demonstrates the usage of DC, stepper and servo motors.

#include <homelab/module/motors.h>
 
int main(void)
{
	// DC motors initialization.
	dcmotor_init(0);
	dcmotor_init(1);
 
	// Bipolar stepper initialization.
	bipolar_init();
 
	// Servo motors initialization.
	servomotor_init(0);
	servomotor_init(1);
 
	// One DC motors drives forward, another in backward direction.
	dcmotor_drive(0, -1);
	dcmotor_drive(1, +1);
 
	// Rotating the stepper motor 100 steps in one direction
	// and then back with twice the speed.
	bipolar_halfstep(1, 100, 50);
	bipolar_halfstep(-1, 100, 25);
 
	// Rotating servo motors in opposite directions.
	servomotor_position(0, -100);
	servomotor_position(1, +100);
}

This example demonstrates the speed adjustments of a DC motor.

#include <homelab/module/motors.h>
 
int main(void)
{
        unsigned char speed = 0;
 
	// DC motors initialization
  	dcmotor_drive_pwm_init(0, TIMER2_NO_PRESCALE);
 
  	while(1)
  	{   	
		speed = 100;
 
		// DC motors drives predefined speed and direction.
		dcmotor_drive_pwm(0, 1, speed);			      
  	}
}