Нашла на сайте, что можно, подключила как сказано, но при запуске загорелся диод, не просто поморгал, а непрерывно горел всё время, после чего ардуино вообще перестало подавать признаки жизни. На питании и кнопке Reset напряжение есть. Где-то читала что можно перепрошить. Но хотелось бы узнать о причинах. Вот код: 

#define pulPin 14
#define dirPin 15
#define enablePin 16


#define numMsInOneSec 10000
#define numMicroSecInOneMs 10000
#define stepPulseWidthInMicroSec 2
#define setupTimeInMicroSec 1

#define inputBufferSize 128

#include <LiquidCrystal.h>


int  serialCharIn;             
char serialInString[inputBufferSize];  
int  serialInIndex  = 0;

int angle=0;
int fadeAmount = 10;// shag izmeneniya
int changeProp = 0;//tumdler pereklju4enija rezhymov

unsigned long currentTime;
unsigned long loopTime;

const int pin_A = 6;
const int pin_B = 7;

unsigned char encoder_A;
unsigned char encoder_B;
unsigned char encoder_A_prev=0;

unsigned long timeBetweenInputPollsInMicroSec = ( (unsigned long)(numMsInOneSec /4) * numMicroSecInOneMs ); // 250 = 1/4th of a second
unsigned long timeBetweenStepsInMicroSec = (1 * numMicroSecInOneMs);

unsigned long loopCheck = 0;

boolean successfullyParsed = false;
boolean currentDirection = false;
boolean shouldStep = true;
boolean dir = false;
boolean StepChange = false;
boolean speedChanged = true;

    LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

 
void setCurrentDirection(boolean dir)
 {
   if(dir == false)
  {
     digitalWrite(dirPin, LOW);
    } else {
     digitalWrite(dirPin, HIGH);
    }
    currentDirection = dir;
    delayMicroseconds(setupTimeInMicroSec);//задержка
  } 
 
 void changeDirection()
  {
   setCurrentDirection(!currentDirection);
  }
  
  
 void enableStepper(int isEnabled)
{
  if(isEnabled)
  {
     digitalWrite(enablePin, LOW); // enable LOW = stepper driver ON
  } else {
      digitalWrite(enablePin, HIGH); // enable HIGH = stepper driver OFF
  } 
      delayMicroseconds(2);
  }
   
    
  void takeSinglePul()
{
    digitalWrite(pulPin, LOW);
    delayMicroseconds(stepPulseWidthInMicroSec); 
    digitalWrite(pulPin, HIGH); 
    delayMicroseconds(stepPulseWidthInMicroSec); 
    digitalWrite(pulPin, LOW);
  
}


 void setup() 
{
  // We set the enable pin to be an output 
  pinMode(pulPin, OUTPUT); 
  pinMode(dirPin, OUTPUT);
  pinMode(enablePin, OUTPUT);
  enableStepper(false);
  
  setCurrentDirection(false);
  enableStepper(true);
  setCurrentDirection(true);
  
pinMode(pin_A, INPUT);
pinMode(pin_B, INPUT);

currentTime = millis();
loopTime = currentTime;
  
    lcd.begin(16, 2);  
    lcd.print("stepper  v.2");// Print a message to the LCD.
  }
  void loop() 
   {
     currentTime = millis();
  int j;
  int loops, ramp;
  int rampspeed=4;  // bigger numbers = quicker ramp
   
   
encoder_A_prev = encoder_A;
     
changeProp=analogRead(5);
     
 if (changeProp>0&&changeProp<1024){         
    if (currentTime >= (loopTime + 10)){  
  
       encoder_A = digitalRead(pin_A);
       encoder_B = digitalRead(pin_B);
       
      if((!encoder_A) && (encoder_A_prev)) {
         if(encoder_B){
           
          if (angle + fadeAmount <= 140){
          angle +=fadeAmount;
          
          for (loops=0; loops<(360/10); loops++) {
          enableStepper(true);
          takeSinglePul();
          delayMicroseconds(timeBetweenStepsInMicroSec*2);}
          }
         }
      }
      
         else {
          if (angle + fadeAmount>=0);{
          angle-=fadeAmount;
     
          for (loops=0; loops<(360/10); loops++) {
          enableStepper(true);
          takeSinglePul();}
          delayMicroseconds(timeBetweenStepsInMicroSec);}
         } 
    }
 }
 else {
        
          for(j=0; j<10; j++) { 
          takeSinglePul();
          delayMicroseconds(timeBetweenStepsInMicroSec);}
    lcd.setCursor(0, 0);
    lcd.print(timeBetweenStepsInMicroSec);
    lcd.print("       ");
      }
      
     encoder_A_prev = encoder_A;
     loopTime = currentTime;  
              
    lcd.setCursor(0, 1);
    lcd.print(angle);
    
       }