// NO library 

int stepPin[] = {11, 9, 7, 5, 3}; // motor step pins
int dirPin[]  = {10, 8, 6, 4, 2}; // motor direction pins

#define stepsPerRevolution 200
#define steps 200

byte counter;

void setup() {
  Serial.begin(115200);
  randomSeed(analogRead(A0)); // for random pick of motor and direction

  for (int i = 0; i < 5; i++) {
    pinMode(stepPin[i], OUTPUT);
    pinMode(dirPin[i], OUTPUT);
  }
}

void loop() {
  int dir = random (2); // 0 = CW, 1 = CCW
  int mot = random (5); // motor

  Serial.print("(M"); Serial.print(mot); // motor
  Serial.print(" D"); Serial.print(dir); // direction
  Serial.print(") ");

  if (counter++ == 7) { // output formatting
    counter = 0;
    Serial.println();
  }

  runMotor(mot, dir); // make 'mot' motor run in 'dir' direction
  delay(250); // pause between moving motors
}

void runMotor(int motor, bool direction)
{
  digitalWrite(dirPin[motor], direction);

  // this condition is processor-blocking and will not allow multiple events to occur in parallel
  for (int i = 0; i < steps; i++) { // steps per revolutino, typically 200
    digitalWrite(stepPin[motor], HIGH); // start of start pulse
    delayMicroseconds(2000);
    digitalWrite(stepPin[motor], LOW); // end of start pulse
    delayMicroseconds(2000);
  }
}

/*
                  +-------------------------+
         LOW=DSBL | ENABLE    A4988    VMOT | 8-35vdc ---+ 100uf electro cap
                  | MS1                 GND | gnd -------+ pwr spike protect
                  | MS2                  2B | stepper 2B
                  | MS3                  2A | stepper 2A
              SLP | RESET                1A | stepper 1A
              RST | SLEEP                1B | stepper 1B
          stepPin | STEP                VDD | 5vdc
          stepPin | DIR                 GND | gnd
                  +-------------------------+
           MS1	MS2	 MS3   Step resolution
           Low  Low	 Low   Full step
           High Low	 Low   1/2 step
           Low  High Low   1/4 step
           High High Low   1/8 step
           High High High  1/16 step

           SET DRIVER CURRENT LIMIT
           1. Power A4988 driver (Vdd, GND)
           2. Connect RST to SLP
           3. Disconnect motor
           4. Apply USB power
           5. Calculate current limit: Current Limit = Vref ÷ (8 × Rcs)
           6. A current limit of 1A (standard) needs Vref of 540mV
           7. Adjust POT while measuring Vref at GND to POT (metal screw)
           8. If the motor is making a lot of noise,  lower the current limit
*/