#define UP 2
#define DOWN 3
#define SEL 4
#define LF 5
#define RT 6

#define KEYDELAY 100



int i= 0;
int j =0;
int priv = 0;
char buf[32];
int t = 10;

bool LED_STATE = true;


int getKey(){
    if (digitalRead(UP) == LOW) {
      delay(KEYDELAY);
      if(digitalRead(UP) == LOW) {
        return(1);
      }
    }
    if (digitalRead(DOWN) == LOW) {
      delay(KEYDELAY);
      if(digitalRead(DOWN) == LOW) {
        return(2);
      }
    }

    if (digitalRead(SEL) == LOW) {
      delay(KEYDELAY);
      if(digitalRead(SEL) == LOW) {
        return(3);
      }
    }

    if (digitalRead(LF) == LOW) {
      delay(KEYDELAY);
      if(digitalRead(LF) == LOW) {
        return(4);
      }
    }

    if (digitalRead(RT) == LOW) {
      delay(KEYDELAY);
      if(digitalRead(RT) == LOW) {
        return(5);
      }
    }
  return(0);
}



void setup() {
  // put your setup code here, to run once:
 
pinMode(UP, INPUT_PULLUP);
pinMode(DOWN, INPUT_PULLUP);
pinMode(SEL, INPUT_PULLUP);
pinMode(LF, INPUT_PULLUP);
pinMode(RT, INPUT_PULLUP);

 cli();                      //stop interrupts for till we make the settings
  /*1. First we reset the control register to amke sure we start with everything disabled.*/
  TCCR1A = 0;                 // Reset entire TCCR1A to 0 
  TCCR1B = 0;                 // Reset entire TCCR1B to 0
 
  /*2. We set the prescalar to the desired value by changing the CS10 CS12 and CS12 bits. */  
  TCCR1B |= B00000100;        //Set CS12 to 1 so we get prescalar 256  
  
  /*3. We enable compare match mode on register A*/
  TIMSK1 |= B00000010;        //Set OCIE1A to 1 so we enable compare match A 
  
  /*4. Set the value of register A to 31250*/
  OCR1A = 31250;             //Finally we set compare register A to this value  
  sei();


}

void loop() {
  // put your main code here, to run repeatedly:
    
  if(getKey()!=0) {
    Serial.println("P");
  }

}

ISR(TIMER1_COMPA_vect){
  TCNT1  = 0; 
  t--;   
  if(t==0) {              //First, set the timer back to 0 so it resets for next interrupt
  LED_STATE = !LED_STATE;      //Invert LED state
  digitalWrite(13,LED_STATE);
  t=10;
    }  //Write new state to the LED on pin D5
}