#include <Arduino.h>
#include <U8g2lib.h>

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif

 U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);

#define CLK_PIN 2
#define DT_PIN  3
int lastClk = HIGH;

#define DIRECTION_CW 0   // clockwise direction
#define DIRECTION_CCW 1  // counter-clockwise direction

volatile int counter = 0;
volatile int direction = DIRECTION_CW;
volatile unsigned long last_time;  // for debouncing
int prev_counter;

int FM = 60;
String Freq="60";

void ISR_encoderChange() {
  if ((millis() - last_time) < 50)  // debounce time is 50ms
    return;

  if (digitalRead(DT_PIN) == HIGH) {
    // the encoder is rotating in counter-clockwise direction => decrease the counter
    counter--;
    FM--;
    direction = DIRECTION_CCW;
  } else {
    // the encoder is rotating in clockwise direction => increase the counter
    counter++;
    FM++;
    direction = DIRECTION_CW;
  }

  last_time = millis();
}

void setup(){
	u8g2.begin();
	 Serial.begin(115200);
  pinMode(CLK_PIN, INPUT);
  pinMode(DT_PIN, INPUT);
  attachInterrupt(digitalPinToInterrupt(CLK_PIN), ISR_encoderChange, RISING);
}

void loop(){
 
 if (prev_counter != counter) {
    Serial.print("DIRECTION: ");
    if (direction == DIRECTION_CW)
      Serial.print("Clockwise");
    else
      Serial.print("Counter-clockwise");

    Serial.print(" | COUNTER: ");
    Serial.println(counter);

    prev_counter = counter;
  }

 

Freq = String(FM);
u8g2.clearBuffer();
u8g2.setFontMode(1);
u8g2.setBitmapMode(1);
u8g2.setFont(u8g2_font_6x12_tr);

u8g2.drawStr(19, 20, "FM ");

u8g2.drawStr(46, 20, Freq.c_str());
u8g2.drawFrame(7, 24, FM, 3);

u8g2.sendBuffer();




}