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root / scout_avr / src / stepper.cpp @ 2853d46b

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extern "C"
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{
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#include <avr/io.h>
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#include <util/delay.h>
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}
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#include "stepper.h"
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/*  Stepper Motor:
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 *  Provides interface to stepper motor.
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 *  Can set direction. Outputs pulse to stepper upon call of step func
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 *  Also provides variable speed sweep
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 */
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struct step_t {
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  int pos; // position in rotation.
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  int dir; // direction. -1 CCW. 1 CW. 0 OFF
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  int step_size; // amount to add to position each step
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  int ccw;
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  int cw;
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} step;
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void step_init()
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{
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  /* init pos and dir to 0 */
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  step.pos = 0;
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  step.dir = 0;
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  //set control pins as output
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  DDRD |= ((1<<S_STEP) | (1<<S_DIR));
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  DDRB |= ((1<<S_MS));
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  //initiate to full steps
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  step_set_size(STEP_WHOLE);
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  //initiate the step pin to be low. stepper steps on low to high
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  PORTD &= (~(1<<S_STEP));
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}
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void step_set_size(char size)
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{
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  if (size == STEP_WHOLE)
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  {
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    PORTB &= ~_BV(S_MS);
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    step.step_size = 2;
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  }
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  else
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  {
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    PORTB |= _BV(S_MS);
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    step.step_size = 1;
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  }
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}
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/* set direction pin */
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void step_dir(int dir)
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{
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  step.dir = dir;
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  switch(dir)
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  {
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    case 1:
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      PORTD |= (1<<S_DIR);
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      break;
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    case -1:
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      PORTD &= (~(1<<S_DIR));
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      break;
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  }
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}
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void step_do_step()
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{
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  if(step.dir==0) return; //do not step if not enabled
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  PORTD |= (1<<S_STEP); //step once 
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  _delay_us(1); //conform with step timing
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  PORTD &= (~(1<<S_STEP)); //bring the step bin back down
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  if(step.dir==1) step.pos += step.step_size;
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  else step.pos -= step.step_size;
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}
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void step_flush()
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{
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  PORTD &= (~(1<<S_STEP)); //bring the step bin back down
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}
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//ccw must be less than 0 and cw must be greater than 0
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void step_sweep_bounds(int ccw, int cw)
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{
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  step.ccw = ccw;
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  step.cw = cw;
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}
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void step_sweep()
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{
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  step_do_step();
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  if((step.dir == 1) && (step.cw <= step.pos)) step_dir(-1);
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  else if((step.dir == -1) && (step.ccw >= step.pos)) step_dir(1);
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}