Arduino with TB6600 using AccelStepper library

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//The code belongs to the following tutorial video: https://youtu.be/AR0un3kg-iM

/*
Please consider buying the parts using the following links in order to support my work:
Arduino UNO: https://www.banggood.com/custlink/33KKF85c3i
TB6600 Stepper Driver: https://www.banggood.com/custlink/KvvvZr1Pmj
Variable Power Supply: https://www.banggood.com/custlink/DGKvSpwFvQ
NEMA17: https://www.banggood.com/custlink/vGK3ic1tm2
*/

#include <AccelStepper.h>

long receivedMMdistance = 0; //distance in mm from the computer
long receivedDelay = 0; //delay between two steps, received from the computer
long receivedAcceleration = 0; //acceleration value from computer
char receivedCommand; //character for commands
/* s = Start (CCW) // needs steps and speed values
 * o = open (CCW) // needs steps and speed values
 * c = close (CW) //needs steps and speed values
 * a = set acceleration // needs acceleration value
 * n = stop right now! // just the 'n' is needed
 */

bool newData, runallowed = false; // booleans for new data from serial, and runallowed flag



// direction Digital 9 (CCW), pulses Digital 8 (CLK)
AccelStepper stepper(1, 8, 9);


void setup()
{
  Serial.begin(9600); //define baud rate
  Serial.println("Testing Accelstepper"); //print a message

  //setting up some default values for maximum speed and maximum acceleration
  stepper.setMaxSpeed(2000); //SPEED = Steps / second
  stepper.setAcceleration(1000); //ACCELERATION = Steps /(second)^2

  stepper.disableOutputs(); //disable outputs, so the motor is not getting warm (no current)


}

void loop()
{

  checkSerial(); //check serial port for new commands

  continuousRun2(); //method to handle the motor

}


void continuousRun2() //method for the motor
{
  if (runallowed == true)
  {
    if (abs(stepper.currentPosition()) < receivedMMdistance) //abs() is needed because of the '<'
    {
      stepper.enableOutputs(); //enable pins
      stepper.run(); //step the motor (this will step the motor by 1 step at each loop)
    }
    else //program enters this part if the required distance is completed
    {

      runallowed = false; //disable running -> the program will not try to enter this if-else anymore
      stepper.disableOutputs(); // disable power
      Serial.print("POS: ");
      Serial.println(stepper.currentPosition()); // print pos -> this will show you the latest relative number of steps
      stepper.setCurrentPosition(0); //reset the position to zero
      Serial.print("POS: ");
      Serial.println(stepper.currentPosition()); // print pos -> this will show you the latest relative number of steps; we check here if it is zero for real
    }


  }
  else //program enters this part if the runallowed is FALSE, we do not do anything
  {
    return;

  }
}

void checkSerial() //method for receiving the commands
{
  //switch-case would also work, and maybe more elegant

  if (Serial.available() > 0) //if something comes
  {
    receivedCommand = Serial.read(); // this will read the command character
    newData = true; //this creates a flag
  }

  if (newData == true) //if we received something (see above)
  {
    //START - MEASURE
    if (receivedCommand == 's') //this is the measure part
    {
      //example s 2000 500 - 2000 steps (5 revolution with 400 step/rev microstepping) and 500 steps/s speed
      runallowed = true; //allow running


      receivedMMdistance = Serial.parseFloat(); //value for the steps
      receivedDelay = Serial.parseFloat(); //value for the speed

      Serial.print(receivedMMdistance); //print the values for checking
      Serial.print(receivedDelay);
      Serial.println("Measure "); //print the action
      stepper.setMaxSpeed(receivedDelay); //set speed
      stepper.move(receivedMMdistance); //set distance

    }
    //START - OPEN
    if (receivedCommand == 'o') //OPENING
    {
      //example o 2000 500 - 2000 steps (5 revolution with 400 step/rev microstepping) and 500 steps/s speed
      runallowed = true; //allow running



      receivedMMdistance = Serial.parseFloat(); //value for the steps
      receivedDelay = Serial.parseFloat(); //value for the speed

      Serial.print(receivedMMdistance); //print the values for checking
      Serial.print(receivedDelay);
      Serial.println("OPEN "); //print the action
      stepper.setMaxSpeed(receivedDelay); //set speed
      stepper.move(receivedMMdistance); //set distance

    }

    //START - CLOSE
    if (receivedCommand == 'c') //CLOSING - Rotates the motor in the opposite direction as opening
    {
      //example c 2000 500 - 2000 steps (5 revolution with 400 step/rev microstepping) and 500 steps/s speed; will rotate in the other direction
      runallowed = true; //allow running



      receivedMMdistance = Serial.parseFloat(); //value for the steps
      receivedDelay = Serial.parseFloat(); //value for the speed

      Serial.print(receivedMMdistance);  //print the values for checking
      Serial.print(receivedDelay);
      Serial.println("CLOSE "); //print action
      stepper.setMaxSpeed(receivedDelay); //set speed
      stepper.move(-1 * receivedMMdistance); ////set distance - negative value flips the direction

    }

    //STOP - STOP
    if (receivedCommand == 'n') //immediately stops the motor
    {
      runallowed = false; //disable running

      stepper.setCurrentPosition(0); // reset position
      Serial.println("STOP "); //print action
      stepper.stop(); //stop motor
      stepper.disableOutputs(); //disable power

    }

    //SET ACCELERATION
    if (receivedCommand == 'a') //Setting up a new acceleration value
    {
      runallowed = false; //we still keep running disabled, since we just update a variable

      receivedAcceleration = Serial.parseFloat(); //receive the acceleration from serial

      stepper.setAcceleration(receivedAcceleration); //update the value of the variable

      Serial.println("ACC Updated "); //confirm update by message

    }

  }
  //after we went through the above tasks, newData becomes false again, so we are ready to receive new commands again.
  newData = false;


}