CookieClicker3 click mouse-button with TimerOne library

cookieclicker3.ino

#include <TimerOne.h>
// CookieClicker TimerOne version
// 20130919

const int ABTN=8;
const int BBTN=9;
const int CBTN=10;

const int LED=13;

// SoftwareSerial LedSerial(2,3); // for UNO


void setup() {
  // Serial.begin(9600);
  // while(!Serial);
  // LedSerial.begin(9600);
  Serial1.begin(9600); // for Leonardo
  while(!Serial1);

  Mouse.begin();

  pinMode(ABTN,INPUT_PULLUP);
  pinMode(BBTN,INPUT_PULLUP);
  pinMode(CBTN,INPUT_PULLUP);

  pinMode(LED,OUTPUT);

  Timer1.initialize();
  Timer1.attachInterrupt(readkey,30000); // 30ms 

}

int trig=0;
int i;

const int countMIN=0;
const int countMAX=999;
int counter=50;

volatile int Send=0;
volatile int Up=0;
volatile int Down=0;

volatile int Psend=0;
volatile int Pup=0;
volatile int Pdown=0;

void loop() {

  noInterrupts();

  if (Down==1 && counter>countMIN) {
     counter--;
     Down=0;
  }
  if (Up==1 && counter<countMAX) {
     counter++;
     Up=0;
  }
  if (Send==1) {
    trig=!trig;
    Send=0;
  }

  Serial1.write(0x76);
  Serial1.print(counter,DEC);

  interrupts();

  if (trig) {
      digitalWrite(LED,1);
      Mouse.click();
  }

  for(i=0;i<=counter;i++) {
      delay(1);
      digitalWrite(LED,0);
  }
}

void readkey() {
  int key;
  key=digitalRead(ABTN);
  if (key==LOW && Pdown==LOW) Down=1;
  Pdown=key;
  key=digitalRead(BBTN);
  if (key==LOW && Pup==LOW) Up=1;
  Pup=key;
  key=digitalRead(CBTN);
  if (key==LOW && Psend==LOW) Send=1;
  Psend=key;
}