#define MAX_STEP 400
#define DEBUG 1

/*
Direction
*/
void dir(int k)
{
  if(k == 0)
  {
    digitalWrite(2, LOW);
  }
  else if(k == 1)
  {
    digitalWrite(2, HIGH);
  }
}

/*
Step
*/
void step(void)
{
  digitalWrite(3, HIGH);
  delay(1);
  digitalWrite(3, LOW);
  delay(1);
}

/*
Setup
*/
void setup(void) 
{
  if(DEBUG == 1)
  {
    Serial.begin(115200);
  }
  else
  {
    Serial.end();
  }
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  dir(0);
}

/*
Nema-17 200step 360°
Half tour 60x1000mS
A4988 setup 1/4 => EN = 0, MS1 = 0, MS2 = 1, MS3 = 0, VMOT = PSU +12V, VDD = +5V, GND1 + GND2 + Arduino GND = PSU GND
if you wanna, PSU +5V and Arduino +5V can merge.
All GND should be merged.
400 step half tour 
(60 x 1000) / 400 = 150mS
*/
void loop(void) 
{
  dir(0);
  for(int i = 0; i < MAX_STEP; i++)
  {
    if(DEBUG == 1)
    {
      Serial.print(i);
      Serial.println(" step Left");
    }

    step();
    delay(150);
  }
  dir(1);
  for(int i = 0; i < MAX_STEP; i++)
  {
    if(DEBUG == 1)
    {
      Serial.print(i);
      Serial.println(" step Right");
    }
    step();
    delay(150);
  }
}