#define UD  2                          // OUTPUT

#define INC 3

#define CS  4

void up(){

  digitalWrite(UD, HIGH);

  digitalWrite(INC, HIGH);

  digitalWrite(CS, LOW);              // turn on the microcircuit

  delayMicroseconds(1);

  digitalWrite(INC, LOW);

  delayMicroseconds(1);

  digitalWrite(INC, HIGH);

  delayMicroseconds(1);

///digitalWrite(INC, LOW);            // in this case the position of the slider is not written

  digitalWrite(CS, HIGH);             // turn off the chip and write the position in the EEPROM

}

void down()

{

  digitalWrite(UD, LOW);

  digitalWrite(INC, HIGH);

  digitalWrite(CS, LOW);

  delayMicroseconds(1);

  digitalWrite(INC, LOW);

  delayMicroseconds(1);

  digitalWrite(INC, HIGH);

  delayMicroseconds(1);

  digitalWrite(CS, HIGH);

}

void setup() {

  Serial.begin(9600);

  pinMode(INC, OUTPUT);

  pinMode(UD, OUTPUT);

  pinMode(CS, OUTPUT);

  digitalWrite(CS, HIGH);                         // turn off the microcircuit

}

void loop() {

  if (Serial.available())

     if (Serial.read() == '0'){

      down();

      Serial.print("-1");

     }

     else {

      up();

      Serial.print("+1");

     }

  }

}