Test four-wire stepper motor with Propeller QuickStart board and A4988 stepper motor driver

test_stepper_motor.c

/*
 * Press button FORWARD_BUTTON_ID to drive forward/backward and BACKWARD_BUTTON_ID to drive backward/forward respectively.
 *
 * How to compile:
 * $ propeller-elf-gcc -mlmm -std=c99 test_stepper_motor.c -o test_stepper_motor
 *
 * How to load (EEPROM) and run:
 * $ propeller-load -r -e test_stepper_motor
 */

#include <propeller.h>

#define FORWARD_BUTTON_ID  7
#define BACKWARD_BUTTON_ID 5

#define STEP_PIN      8
#define DIRECTION_PIN 9

#define STEP_DELAY 10

#define PAUSE(time) waitcnt((time * (CLKFREQ / 1000)) + CNT)

int main() {
  int result;
  char pin;

  _DIRA |= 1 << STEP_PIN;
  _DIRA |= 1 << DIRECTION_PIN;

  while (1) {
    result = INA & (unsigned)(0xFF);
    for (pin = 0; pin < 16; pin++, result >>= 1) {
      if ((result & 1UL) == 0) {
        _OUTA &= ~(1 << (pin + 16));
      } else {
        _OUTA |= 1 << (pin + 16);
      }
      if (result & 1UL) {
        switch (pin) {
        case FORWARD_BUTTON_ID:
          _OUTA |= 1 << DIRECTION_PIN;
          break;
        case BACKWARD_BUTTON_ID:
          _OUTA &= ~(1 << DIRECTION_PIN);
          break;
        }
        _OUTA |= 1 << STEP_PIN;
        PAUSE(STEP_DELAY);
        _OUTA &= ~(1 << STEP_PIN);
        PAUSE(STEP_DELAY);
      }
    }
  }
  return 0;
}