1. What does the potasiometer on the bottom-left is doing?
2. Which pin does the Stop button connects when Mega is connected with RAMPS 1.4 and LCD?
3. How can I dim the back light of the LCD?

// Steppers
//
#define X_STEP_PIN                            54
#define X_DIR_PIN                             55
#define X_ENABLE_PIN                          38
#ifndef X_CS_PIN
  #define X_CS_PIN                            53
#endif

// Include the AccelStepper Library
//#include (AccelStepper.h) //Correct Parenthesis

#define X_STEP_PIN                            54
#define X_DIR_PIN                             55
#define X_ENABLE_PIN                          38

// Define motor interface type
#define MotorInterfaceType 1

// Creates an instance
AccelStepper myStepper(MotorInterfaceType,X_STEP_PIN,X_DIR_PIN);

void setup() {
  // set the maximum speed, acceleration factor,
  // initial speed and the target position
  pinMode(X_ENABLE_PIN,OUTPUT);
  digitalWrite(X_ENABLE_PIN,LOW);

 // myStepper.setCurrent(0);
  
 // myStepper.setMaxSpeed(1000);
  myStepper.setAcceleration(2000);
  myStepper.setSpeed(1000);
  myStepper.moveTo(1600);
  
}

void loop() {
  // Change direction once the motor reaches target position
  if (myStepper.distanceToGo() == 0) 
    myStepper.moveTo(-myStepper.currentPosition());

  // Move the motor one step
  myStepper.run();
}

• Arduino Mega 2560
• Ramps 1.6
• Drv 8825
• Nema 17 (17HS4401)
• LCD 128x64 with SDCard
• Marlin
• Pronterface

U8GLIB_ST7920_128X64_1X u8g(23, 17, 16); // SPI Com: SCK = en = 23, MOSI = rw = 17, CS = di = 16

#define ST7920_CLK_PIN  23
#define ST7920_DAT_PIN  17
#define ST7920_CS_PIN   16

• Arduino Uno
• CNC Shield
• Drv8825
• Nema 17 (17HS4401)
• GRBL
• Pronterface

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