Converting analog to digital

OK, if you want an hysteresis you would do something like this

const int lowToHighThreshold = 600;
const int HighToLowThreshold = 400;

const byte joystickPin = A0;
byte joystickState = LOW;

const byte outputPin = 13;

void setup() {
  pinMode(outputPin, OUTPUT);
  digitalWrite(outputPin, joystickState);
}

void loop() {
  if (joystickState == LOW) {
    if (analogRead(joystickPin) > lowToHighThreshold)  {
      digitalWrite(outputPin, HIGH);
      joystickState = HIGH;
    }
  } else {
    if (analogRead(joystickPin) < HighToLowThreshold)  {
      digitalWrite(outputPin, LOW);
      joystickState = LOW;
    }
  }
}

(typed here so mind typos)