// https://forum.arduino.cc/t/running-two-stepper-motors-at-once/1115352

#include <AccelStepper.h>

#define dirPinLeft 7          /// direction left
#define stepPinLeft 8         /// step left
#define motorInterfaceType 1  /// bipolar motor

AccelStepper stepperLeft = AccelStepper(motorInterfaceType, stepPinLeft, dirPinLeft);

const int enPin1 = 9;                      /// enable pin 1
int processEnablerStateVariableCount = 5;  // global state variable for remembering how many times to go

void setup() {
  pinMode(enPin1, INPUT);
  digitalWrite(enPin1, HIGH);     /// disable motor control

  stepperLeft.setMaxSpeed(100);  /// slow is 100, fast is 900000
  stepperLeft.setAcceleration(50);
  stepperLeft.moveTo(15);
}

void loop() {
  slowMove1();
}

void slowMove1() {  /// motors are NOT disabled at end of function
  digitalWrite(enPin1, LOW);  /// enable motor control

  if (stepperLeft.distanceToGo() == 0 && processEnablerStateVariableCount > 0) {
    stepperLeft.moveTo(-stepperLeft.currentPosition());
    --processEnablerStateVariableCount;  /// reduce the count by one
  }
  stepperLeft.run();

    digitalWrite(enPin1, HIGH);  /// disable motor control
}