How To Control a Stepper Motor with A4988 Driver and Arduino

In this Arduino Tutorial we will learn how to control a Stepper Motor using the A4988 Stepper Driver. You can watch the following video or read the written tutorial below.

Overview


The A4988 is a microstepping driver for controlling bipolar stepper motors which has built-in translator for easy operation. This means that we can control the stepper motor with just 2 pins from our controller, or one for controlling the rotation direction and the other for controlling the steps.

A4988-Stepper-Driver

The Driver provides five different step resolutions: full-step, haft-step, quarter-step, eight-step and sixteenth-step. Also, it has a potentiometer for adjusting the current output, over-temperature thermal shutdown and crossover-current protection.

Its logic voltage is from 3 to 5.5 V and the maximum current per phase is 2A if good addition cooling is provided or 1A continuous current per phase without heat sink or cooling.

A4988-Specifications

A4988 Stepper Driver Pinout


Now let’s close look at the pinout of the driver and hook it up with the stepper motor and the controller. So we will start with the 2 pins on the button right side for powering the driver, the VDD and Ground pins that we need to connect them to a power supply of 3 to 5.5 V and in our case that will be our controller, the Arduino Board which will provide 5 V.  The following 4 pins are for connecting the motor. The 1A and 1B pins will be connected to one coil of the motor and the 2A and 2B pins to the other coil of the motor. For powering the motor we use the next 2 pins, Ground and VMOT that we need to connect them to Power Supply from 8 to 35 V and also we need to use decoupling capacitor with at least 47 µF for protecting the driver board from voltage spikes.

A4988-Wiring-Diagram

The next two 2 pins, Step and Direction are the pins that we actually use for controlling the motor movements. The Direction pin controls the rotation direction of the motor and we need to connect it to one of the digital pins on our microcontroller, or in our case I will connect it to the pin number 4 of my Arduino Board.  With the Step pin we control the mirosteps of the motor and with each pulse sent to this pin the motor moves one step. So that means that we don’t need any complex programming, phase sequence tables, frequency control lines and so on, because the built-in translator of the A4988 Driver takes care of everything. Here we also need to mention that these 2 pins are not pulled to any voltage internally, so we should not leave them floating in our program.

Next is the SLEEP Pin and a logic low puts the board in sleep mode for minimizing power consumption when the motor is not in use.

Next, the RESET pin sets the translator to a predefined Home state. This Home state or Home Microstep Position can be seen from these Figures from the A4988 Datasheet. So these are the initial positions from where the motor starts and they are different depending on the microstep resolution. If the input state to this pin is a logic low all the STEP inputs will be ignored. The Reset pin is a floating pin so if we don’t have intention of controlling it with in our program we need to connect it to the SLEEP pin in order to bring it high and enable the board.

A4988-Truth-Table1

The next 3 pins (MS1, MS2 and MS3) are for selecting one of the five step resolutions according to the above truth table. These pins have internal pull-down resistors so if we leave them disconnected, the board will operate in full step mode.

The last one, the ENABLE pin is used for turning on or off the FET outputs. So a logic high will keep the outputs disabled.

Components needed for this Arduino Tutorial


You can get the components from any of the sites below:

*Please note: These are affiliate links. I may make a commission if you buy the components through these links.
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Circuit Schematics


Here’s the complete circuit schematics. I will use the drive in Full Step Mode so I will leave the 3 MS pins disconnected and just connect the Direction and the Step pins of the drive to the pins number 3 and 4 on the Arduino Board and as well the Ground and the 5 V pins for powering the board. Also I will use a 100µF capacitor for decoupling and 12V, 1.5A adapter for powering the motor. I will use a NEMA 17 bipolar Stepper Motor and its wires A and C will be connected to the pins 1A and 1B and the B and D wires to the 2A and 2B pins.

Controlling-Stepper-Motor-Circuit-Schematics

Current Limiting


Before we connect the motor we should adjust the current limiting of the driver so that we are sure that the current is within the current limits of the motor. We can do that by adjusting the reference voltage using the potentiometer on the board and considering this equation: Current Limit = VRef x 2

Reference-Voltage-Measurement3

However this equation is not always correct as there are different manufactures of the A4988 driver board. Here’s a demonstration of my case: I adjusted the potentiometer and measured 0.6V reference voltage. So the current limiting should be that value of 0.6*2, equal 1.2 A.

Reference-Voltage-Measurement4

Now because I am using the Driver in Full Step Mode and according to the A4988 Datasheet in this mode the winding current could reach only 70% of the current limit, the 1.2A*0.7 would equal 0.84A. In order to check this I uploaded a simple code that sends continuous logic high to the Step pin (so that we can better notice the current) and connected my meter in series with one winding of the motor and powered it up. What I got was 0.5A which means that the equation wasn’t correct for my case.

Reference-Voltage-Measurement5


Source Code


Here’s an example code. First we have to define the Step and Direction pins. In our case they are the pins number 3 and 4 on the Arduino Board and they are named stepPin and dirPin and the setup section we have to define them as an outputs.

/*     Simple Stepper Motor Control Exaple Code
 *      
 *  by Dejan Nedelkovski, www.HowToMechatronics.com
 *  
 */

// defines pins numbers
const int stepPin = 3; 
const int dirPin = 4; 
 
void setup() {
  // Sets the two pins as Outputs
  pinMode(stepPin,OUTPUT); 
  pinMode(dirPin,OUTPUT);
}
void loop() {
  digitalWrite(dirPin,HIGH); // Enables the motor to move in a particular direction
  // Makes 200 pulses for making one full cycle rotation
  for(int x = 0; x < 200; x++) {
    digitalWrite(stepPin,HIGH); 
    delayMicroseconds(500); 
    digitalWrite(stepPin,LOW); 
    delayMicroseconds(500); 
  }
  delay(1000); // One second delay
  
  digitalWrite(dirPin,LOW); //Changes the rotations direction
  // Makes 400 pulses for making two full cycle rotation
  for(int x = 0; x < 400; x++) {
    digitalWrite(stepPin,HIGH);
    delayMicroseconds(500);
    digitalWrite(stepPin,LOW);
    delayMicroseconds(500);
  }
  delay(1000);
}

In the loop section first we will set the Direction pin on high state that will enable the motor to move in a particular direction. Now using this for loop we will make the motor make one full cycle rotation.  As the driver is set on Full Step Mode and our Stepper Motor has 1.8 degrees step angle, or 200 steps, we need to send 200 pulses into the Step Pin to make one full cycle rotation. So the for loop will have 200 iterations and each time it will set the Step pin on high and then low state for making the pulses. Between each digitalWrite we need add some delay from which the speed of the motor will depend.

After this full cycle rotation we will make one second delay, then change the direction of rotation by setting the dirPin on a low state and now make 2 full cycle rotations with this loop of 400 iterations. At the end there is one more second delay. Now let’s upload the code and see how it will work.

I made one more example for this tutorial, where I control the speed of the motor using a potentiometer. Here’s the source code of that example:

/*     Simple Stepper Motor Control Exaple Code
 *      
 *  by Dejan Nedelkovski, www.HowToMechatronics.com
 *  
 */
 
// Defines pins numbers
const int stepPin = 3;
const int dirPin = 4; 

int customDelay,customDelayMapped; // Defines variables
 
void setup() {
  // Sets the two pins as Outputs
  pinMode(stepPin,OUTPUT);
  pinMode(dirPin,OUTPUT);
 
  digitalWrite(dirPin,HIGH); //Enables the motor to move in a particular direction
}
void loop() {
  
  customDelayMapped = speedUp(); // Gets custom delay values from the custom speedUp function
  // Makes pules with custom delay, depending on the Potentiometer, from which the speed of the motor depends
  digitalWrite(stepPin, HIGH);
  delayMicroseconds(customDelayMapped);
  digitalWrite(stepPin, LOW);
  delayMicroseconds(customDelayMapped);
}
// Function for reading the Potentiometer
int speedUp() {
  int customDelay = analogRead(A0); // Reads the potentiometer
  int newCustom = map(customDelay, 0, 1023, 300,4000); // Convrests the read values of the potentiometer from 0 to 1023 into desireded delay values (300 to 4000)
  return newCustom;  
}

67 Responses

  1. Andres Tejada

    Hello
    I have a question, could you show the scheme with the potentiometer?
    I don´t know how conect this.

    thaks a lot

    Andres

    Reply
  2. axel

    HI, thanks for the good tutorial. I am using the code you wrote with the potentiometer. However, even when I change

    digitalWrite(dirPin,HIGH); //Enables the motor to move in a particular direction

    TO

    digitalWrite(dirPin,LOW); //Enables the motor to move in a particular direction

    The motor keeps going in the same direction – any idea why?

    thanks

    Reply
    • Dejan Nedelkovski

      Well that’s strange. Try reconnect the driver exactly as explained and try the code again. There’s nothing else you can do, because the DIR pin of the driver is meant for that. Either is LOW or HIGH and the motor should move in different direction.

      Reply
  3. Berat Uslu

    Hello Dejan,

    Thanks for great tut. I followed your tut same. But result is like on the video. After I connecting stepper’s wires to a4988 its like vibrating. Its like affecting kind of magnetic field. It is strange. After I connect the arduino result is like on the video. What can be the problem.
    https://www.youtube.com/watch?v=QeQ7apxoEZs

    Thanks.

    Reply
      • Berat Uslu

        Now its working! I did everything same. How its possible. I am using 12v for powering the stepper 5v for logic. But i was not shure about which coil cables which. I had tried all the combinations. But now its working… Great!.

        Thank you so much.

      • Berat Uslu

        Difference was, I earlier took logic power from another source. Now I am taking it from Arduino. For who encountering same problem.

        Cheers!

  4. Matija

    Hi there. Joining others. Really comprehensive and useful and worth all congrats. Bookmarked!

    Reply
  5. Ralph Brown

    Hi’
    Thanks for this tutorial. I’ve been trying for weeks to run 3 steppers on a Uno with a motor shield and A4988’s. I’ve had no success at all and thinking I had fried everything, bought full replacements, with the same results. Thanks to your tutorial I’ve at last managed to get a positive result. I’ve also now been able to test all the A4988s, my 2 Uno boards and the steppers. Interestingly, I didn’t fry anything! I’ll now need to think about how to test the shields.
    Thanks again, Ralph

    Reply
  6. Argyris

    Hello I’m trying to control a stepper motor with a joystick, a DRV8825 and an arduino uno. I used your tutorial with the potentiometer, but I have some difficulties with the speed . In your tutorial you have only one direction and your values are from 0 to 1023. I want to devide the potentiometer for RIGHT and LEFT direction, any suggestions on how to do that? Also, the speed on my motor is slower than your tutorial(When the motor turns clockwise and anticlockwise). Thanks in advance, still your tutorial was very helpfull.

    Reply
    • Dejan Nedelkovski

      Well you should adjust the delay time between the steps that will suit your driver and stepper capabilities and match your desired speed. As for the potentiometer you should use the map() function and try to map the values you get from the potentiometers into the suitable delay times, as well, probably with an “if” statement, for half of the values make the “dir” variable positive or negative.

      Reply
      • Argyris

        Thanks for the reply, I manage to fix it and it runs smoothly. Thanks again for a wanderfull tutorial !

  7. Argyris

    Hello again, in your code with the potentiometer, in your function you have the following code : int newCustom = map(customDelay, 0, 1023, 300,4000); // Convrests the read values of the potentiometer from 0 to 1023 into desireded delay values (300 to 4000). My question is, How exactly you found the desirable delay values ? My motor is an Nema 17 stepper motor . Thanks in advance (I’m trying to control 3 motors wireless in my project 🙂 )

    Reply
  8. Nick

    Great tutorial! I got everything to work with the potentiometer after playing around with it for a bit. Now I want to add another motor/potentiometer to the same Arduino board. I tried copying everything you had in potentiometer code and just renamed and add a few variables. I was successfully flashed my code to my Arduino Uno but when I changed one potentiometer both motor speeds would change at the same time. I can’t figure out how to get each motor to work independently. Any suggestions?

    Reply
    • Dejan Nedelkovski

      It got to be the code. In the tutorial example with the potentiometer value we change the delay time between the steps. So you need to make separate delay variables for both motors. You could achieve that if you make separate custom functions outside the main “loop” for both motors so that they have separate delay variables and then you just have to call those custom functions in the main “loop” to be executed.
      Did you get me?

      Reply
      • Nick

        I think I got ya. Here’s what I have. Still learning Arduino code. I the stepper motors don’t want to work independently.

        void loop() {

        customDelayMappedFeed = speedUpFeed(); // Gets custom delay values from the custom speedUp function
        // Makes pules with custom delay, depending on the Potentiometer, from which the speed of the motor depend
        digitalWrite(stepPinFeed, HIGH);
        delayMicroseconds(customDelayMappedFeed);
        digitalWrite(stepPinFeed, LOW);
        delayMicroseconds(customDelayMappedFeed);

        customDelayMappedCut = speedUpCut(); // Gets custom delay values from the custom speedUp function
        // Makes pules with custom delay, depending on the Potentiometer, from which the speed of the motor depend
        digitalWrite(stepPinCut, HIGH);
        delayMicroseconds(customDelayMappedCut);
        digitalWrite(stepPinCut, LOW);
        delayMicroseconds(customDelayMappedCut);

        }

        // Function for reading the Potentiometer
        int speedUpFeed() {
        int customDelayFeed = analogRead(A0); // Reads the potentiometer
        int newCustomFeed = map(customDelayFeed, 0, 1023, 300, 4000); // Convrests the read values of the potentiometer from 0 to 1023 into desireded delay values (300 to 4000)
        return newCustomFeed;
        }

        // Function for reading the Potentiometer
        int speedUpCut() {
        int customDelayCut = analogRead(A1); // Reads the potentiometer
        int newCustomCut = map(customDelayCut, 0, 1023, 300, 4000); // Convrests the read values of the potentiometer from 0 to 1023 into desireded delay values (300 to 4000)
        return newCustomCut;
        }

  9. Robert Friberg

    Hi, I’m building a rubiks cube solving robot using a A4988 driver and bipolar stepper motor for each face of the cube so this article is perfect for me! I’m documenting the project on twitter, see @robertfriberg

    Question: I saw a different tutorial where the grounds between the power and logic circuits are connected. It seems you don’t connect the grounds. What’s the difference?

    Reply
    • Dejan Nedelkovski

      Well, you don’t have to connect them together as they are already connected. The two GND pins of the A4988 board are already internally connected together.

      Reply
  10. Steve OBrien, Sydney, Australia

    Thanks for this tutorial, I have used your information to successfully get my A4988 board & stepper motor project working. It saved me a lot of time! But I did have to change the stepper wiring, the illustration shows the wires straight through from the motor into the A4988 board, but I had to cross them over. My stepper is a NEMA 17HS3001-20B it has 4 wires and similar looking connections on the motor. Would it be worth adding a warning about this in the next version of your page?

    Reply
    • Dejan Nedelkovski

      I’m glad to hear you’ve found it useful! Well there many different manufactures of these motors so each of them might have different order of the pins. So therefor, before connecting, you should always check datasheet of the motor.

      Reply
  11. Manas Bose

    Respected sir,

    I have seen your video on How to control a stepper motor it is a good and nice
    tutorial.

    sir I have question, sir I want to control a stepper motor’s rotation angle from
    0 to 360 and 360 to 0,with a potentiometer. sir there is an example skech in the Arduino software, called
    stepper motorknob. sir in that example skech four control inputs are there,
    by using A4988 driver board that skech is not going to run the motor.

    sir please throw some light on this.

    or can u suggest some skech on this without using library

    thanking you
    Manas

    Reply
    • Dejan Nedelkovski

      Well I don’t have such a code. But here’s a tip how you make that: map the potentiometer values from 0 to the number of steps the stepper motors needs to make a full 360 cycle.

      Reply
  12. miguel

    I have a cuestion , can regulate the speed of UN NEMA 17 with 4 letters of my computer, for example letter a = 0 speed, b= 25 %, c =50 % d= 100, i don want use potentiometer

    Reply
    • Dejan Nedelkovski

      Sure you can, but you have to make a program for that. You could use the Arduino Serial Port to send these signals or use Processing IDE in order to make even cooler interface.

      Reply
      • miguel

        can you help me? im a confused i dont know where to star, i have this materials, Testing A4988 + NEMA17 + Arduino, i dont have idea how to regulate the speed

      • miguel

        I think that is more dificult to have the control of the motor bipolar u.u that motor cd and you have a razon i need to use a serial port

  13. Scat

    Hello, nice tutorial. May I ask what is the difference to drive the motor in Full Step Mode and microstep mode and how to change between the modes?

    Reply
    • Dejan Nedelkovski

      Check my Stepper Motor – How It Works article in order to understand the difference of the modes. And as for this driver, selecting different modes is already explained in the post itself.

      Reply
  14. Manas Bose

    Respected sir,

    Myself Manas Bose, Sir I am working on a project, where I have to control a stepper motor step control with the help of a potentiometer, and arduino the sir I have wrote a skech with the help of a friend attached herewith, it is working fine.

    Sir now I want to make this thing wireless, sir I want to use 2 arduino and 2 xbee, on sending side a arduino, xbee, and a potentiometer will be there. On receiving side a arduino, xbee and a stepper motor will be there. Earlier one setup I made with servo motor.

    Sir, I and my friend don’t have adequate knowledge of c ++, I hereby request u to kindly help
    In the coding, or at least if u can throw some light on it.

    Hope to be favored please
    Thanking you
    Manas

    #include
    int current_position = 0;
    const char direction_pin = 2;
    const char step_pin = 3;
    const char pot_pin = 1; //analog input 1
    void setup()
    {
    pinMode(direction_pin, OUTPUT);
    pinMode(step_pin, OUTPUT);
    pinMode(pot_pin, INPUT);
    }

    void loop()
    {
    int readvalue = analogRead(pot_pin);
    readvalue = map(readvalue,0,1023,0,1151);
    if (readvalue > current_position)
    {
    step_motor_forward();
    current_position += 1;
    }
    else if (readvalue < current_position)
    {
    step_motor_back();
    current_position -= 1;
    }
    }//end of loop

    void step_motor_forward()
    {
    digitalWrite(direction_pin, LOW);
    digitalWrite(step_pin, HIGH);
    digitalWrite(step_pin, LOW);
    }

    void step_motor_back()
    {
    digitalWrite(direction_pin, HIGH);
    digitalWrite(step_pin, HIGH);
    digitalWrite(step_pin, LOW);
    }

    Reply
  15. Jimmy

    Hi Dejan Nedelkovski, congratulation and thank you for sharing this tutorial.
    According the Delay control the speed of the stepper motor in your code, you wrote a delay (500 microseconds). your mapping delay for the potentiometer is between (300; 4000).
    My question … Where did you found these values and their limits ?

    Thank you for your answer

    Jimmy

    Reply
    • Dejan Nedelkovski

      Hi there. Well I made tested them. For example If I set the delay time lower then 250, i think, the stepper wouldn’t start at all. The lowest delay time (fastest speed) I managed to try was like 90, but with higher delay at the start, more then 300, then lowering with the potentiometer to 90.
      Also you could find more details about this, the timing, in the datasheet of the stepper driver.

      Reply
      • Jimmy

        Thank you for the Reply and sharing this tutorial.

        Best Regard.

  16. Olaf

    Hi Dejan,

    Thank you for sharing this tutorial.

    Just wondering; you used a NEMA 17 42BYGHW609 (the ‘get one’ link refers to this type)? It is rated at 3.4 V and 1.68 A.

    Now, the A4988 has a minimum operating voltage of 8 V. Actually, you prescribe a 12 V, 1.5 A power source. Does this not lead to any conflicts?

    Cheers, Olaf

    Reply
    • Dejan Nedelkovski

      Yes the 8V – 35 V are the Motor Supply Voltage so you can connect any adapter you want within that range. The driver will take care of the driving the stepper with the appropriate voltage.

      Reply
  17. lottie

    what type of capacitor should i be using because you said to use a 47 microfered capacitor but the diagram said to use a 100 microfered.what capacitor should i use

    motor: [link]

    cheers

    Reply
  18. Daniel

    Dejan,

    thank you very much, but, can you please better explain that part about current limiting? I have source 12V 1500mA (motor same as you), what should i measure and what to change? I don’t understand it, thank you

    Reply
  19. Kenny

    Great tutorial and thanks. I am up and running thanks to you.

    My only issue is that my NEMA 17 running on an A4988 controller and Uno board is that it will only run one direction. Changing the code does nothing. I can get a direction change by switching the wires around at the controller, but not by changing the code.

    I am very new at this so hopefully it’s something simple.

    Reply
  20. Maddie

    Hi Dejan,

    Thank you for this great tutorial. I have two questions: in the video, the circuitry diagram (the one that looked like a Fritzing image) does not show that the Sleep and Step pins are connected. Yet it appears as if they are at the end of the video? Could you clarify for me which is the correct circuit?

    And secondly, more importantly, I am finding that my stepper motor, an FSM0815-KD95, is getting extremely hot. After checking the voltage of the 1A-2B driver pins, I found that even when my code was simply looping “digitalWrite(stepPin, LOW);” two of the pins are still receiving voltage. Is there anyway that I can make the voltage of all pins 0 while the motor is not running? That way it will not overheat.

    Reply
    • Dejan Nedelkovski

      Hi there and thanks!
      “Step” pin is connected to Arduino, of course, because it gives controls the steps of the motor.
      “Sleep” pin is connected to the “Reset” pin of the driver.
      The motor supply voltage of the A4988 driver is 8 – 35 V accross the VMOT and GND, so your motor might not be suitable for this driver.

      Reply
  21. Mark Granger

    Dejan, great tutorial. Do you mind answering as to what the difference is between this driver and the one used for the 28bjy-48-stepper? Are they interchangeable or each stepper needs to have their own driver board? The one used in that video is much cheaper”

    Thanks,
    Mark

    Reply
    • Dejan Nedelkovski

      Thanks. Sure there is a difference between the drivers. Even if you just look at the basic stats of the drivers you can notice a big difference. Just because one is cheaper doesn’t mean it has lower performances.

      Reply
  22. Cristian

    Hi Dejan!

    First of all, thank you for sharing your tutorial. It is very usefull.

    I have a question with the script in wich i have to use a potentiometer, ¿Is there a way to measure the motor rpm? i mean, i want to know how many revolutions per minute is the motor when i set the potentiometer to a particular state.

    Thanks a lot!

    Reply
    • Dejan Nedelkovski

      Well you will need an encoder for measuring the rpm of the motor. Or you could calculate the rpm if you measure the time the arduino needs to execute the 200 steps (full cycle).

      Reply
  23. Viwawa

    Hi Dejan, thanks for your useful tutorial.

    I’ve got a question, is it possible to control 2 stepper motors at the same time by using 2 drivers? The motor rotation is not the same, for example, I want the first motor to rotate 400 steps CW and the others 800 CCW starting at the same time.
    I’ve already tried to write the code for it, but it the motor doesn’t rotate together, motor B will only starting to rotate after motor A finish rotating.

    Thanks for your help!!

    Reply
  24. Shaun

    Just found your website and the answers to what has has been puzzling me regarding stepper motors. I would like to say thank you for such a well presented precise explanation of how things work and more importantly what is going on in the background, not only have you shared your knowledge but you have also took the time to answer questions. This should be used as a bench mark of how other internet websites/forums should be. THANK YOU for taking the time to teach others !!

    Reply
  25. Brian Tozer

    Hi Dejan.

    Being new to arduino could you please explain for me. In the first example I assume the motor is driven at ‘full speed’ all the time. Then in your second example you alter the speed of the motor using a potentiometer. My question is I want the motor to work at a slow speed all the time, can the potentiometer be replaced by a determined resistor or can it be controlled by a extra line of code in the initial sketch?

    Reply
    • Dejan Nedelkovski

      Hi there. Well in my example the speed of the motor is controlled by adjusting the delay time between the steps of the motor, or if you that a look at the code that’s the following line:
      delayMicroseconds(500);

      So all you have to do is set this value according to your need.

      Reply
  26. Jens Bjørn

    Really good tutorial – showing how to adjust current limits. One should be cautious not to make a short circuit between GND and VDD – like I did. That cost me an Arduino Nano….

    Reply
  27. James Taylor

    Does anyone know where I can get library files for A4988 to use in Diptrace PCB artwork program. Thanks

    Reply
  28. markus

    Great tutorial, thanks for publishing!
    I would like to run two steppers with one arduino and 2 A4988 but with one power supply. Could you please tell how to insert a second stepper?
    Thank you so much!
    Best regards
    Markus

    Reply
    • Dejan Nedelkovski

      Thanks!
      Well it should be much of a problem. You just need to add another driver and connect it the same way as the first one. Also modify the code is similar way.
      You can use the same power supply for the motors but just make sure it has enough power to power both motors.

      Reply
      • Markus

        Hello Dejan,
        thank you for your reply.
        So it is not a problem to connect the power supply through one of the driver? The second stepper is getting enought power through the arduino and the driver number one? Which pins would you use on the microcontroller? P3/P4 and VDD/GND is for driver number 1. Certainly i could use P5/P6 for driver number 2. But is there a second pair of VDD and GND pin?
        Thank you so much!

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