I've been working on a 3D printer and I've come to the last step, which is wiring it all up.

The 3D printer I'm making works ONLY with the Arduino Mega. No Ramps. If I need to get Ramps later, I will, but for now, can someone please help me understand which of the Ramps pin goes with which Arduino pin. For example, in the Repetier firmware, the code is like this:

#define X_STEP_PIN         54
#define X_DIR_PIN          55
#define X_ENABLE_PIN       38
#define X_MIN_PIN           3
#define X_MAX_PIN           2

But Arduino doesn't have a 54 and a 55 pin. I've been googling this and I found that Ramps pins 54 - 69 are the same as pins A0 - A15 on the Arduino Mega.

I know this but not for the other pins...

Can someone please tell me the connection of all the Ramps pins to the Arduino pins?

Like: pin 54 on Ramps = A0 on Arduino. I need this for all of the pins.

  • As explained in schematic, we have Rx and Tx pin and d2* and d3*. If we check in arduino mega pin outs, Rx is D2 pin. this creates the confusion, please explain me the difference between D2 and D2* Sep 1, 2018 at 9:42

2 Answers 2


You are right, your have all the information in your question.

Pin 54 Refers to the Arduino PIN Number, nothing to do with RAMPS. 0-53 are the digital pins and the 54 is A0, etc. So the pin numbers should go higher than 69, which is A15.


You're very close to your answer. Here are the specifics:

Name      software pin  Mega2560 board label
X_STEP_PIN    54         Analog A0
X_DIR_PIN     55         Analog A1
X_ENABLE_PIN  38         Digital 38
X_MIN_PIN     3          PWM 3
X_MAX_PIN     2          PWM 2

http://reprap.org/mediawiki/images/3/3f/Arduinomegapololushieldschematic.png shows the mapping.

  • thanks, but when I insert the pins for the X axis directly on the mega, I doesnt work. I'm using a driver.
    – user25507
    Aug 5, 2016 at 1:50

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