/*
 * 20210313_m32u4_stepper.c
 *
 * Created: 2021-03-13 12:45:31
 * Author : uwezi
 */ 
#define F_CPU 8000000UL

#include <avr/io.h>
#include <util/delay.h>

const uint8_t steps[] = {0b0001, 0b0101, 0b0100, 0b0110, 0b0010, 0b1010, 0b1000, 0b1001};

// bipolar stepper motor connected through a SN754410 driver
// D0 A1
// D1 A2
// D2 B1
// D3 B2

int main(void)
{
  uint8_t i=0;
  uint16_t j;
  
  DDRD  = 0b00001111;
  PORTD = 0b00000000;
   
  while (1) 
  { 
    for (j=0; j<1000; j++)
    {
      PORTD = steps[i];
      i ++;
      i %= 8;
      _delay_ms(1);
    }
    for (j=0; j<1000; j++)
    {
      PORTD = steps[7-i];
      i ++;
      i %= 8;
      _delay_ms(1);
    }
  }
}