rotary_encoder_INT.c

volatile int state = HIGH;
volatile int flag = HIGH;

volatile int Aold = 0;
volatile int Anew = 0;
volatile int Bold = 0;
volatile int Bnew = 0;

static boolean rotating=false;      // debounce management

boolean A_set = false;              
boolean B_set = false;

volatile unsigned int encoderpos = 0;
unsigned int lastReportedPos = 1;

volatile long lastDebounceTime = 0;
volatile long debounceDelay = 1;

int count = 0;

#define encoderpinA PD_0
#define encoderpinB PD_1

#define encoderClick PD_2

void setup()
{
  Serial.begin(9600);

  pinMode(GREEN_LED, OUTPUT);
  digitalWrite(GREEN_LED, state);

  pinMode(encoderpinA, INPUT_PULLUP);
  pinMode(encoderpinB, INPUT_PULLUP);
  pinMode(encoderClick, INPUT_PULLUP);
  attachInterrupt(encoderpinA, doencoderA, CHANGE);
  attachInterrupt(encoderpinB, doencoderB, CHANGE);
  attachInterrupt(encoderClick, blink, FALLING);
}

void loop()
{
  rotating = true; 
  digitalWrite(GREEN_LED, state);
  
  if((lastReportedPos != encoderpos)) {

    Serial.println(encoderpos);
    flag = LOW;
        lastReportedPos = encoderpos;

  }
}

void doencoderAold() {
  Bnew^Aold ? encoderpos++:encoderpos--;
  Aold = digitalRead(encoderpinA);
  flag= HIGH;
}

void doencoderBold() {
  Bnew= digitalRead(encoderpinB);
  Bnew^Aold ? encoderpos++:encoderpos--;
  flag= HIGH;
}

// Interrupt on A changing state
void doencoderA(){
  // debounce
  if ( rotating ) delay (debounceDelay);  // wait a little until the bouncing is done

  // Test transition, did things really change? 
  if( digitalRead(encoderpinA) != A_set ) {  // debounce once more
    A_set = !A_set;

    // adjust counter + if A leads B
    if ( A_set && !B_set ) 
      encoderpos += 1;

    rotating = false;  // no more debouncing until loop() hits again
  }
}

// Interrupt on B changing state, same as A above
void doencoderB(){
  if ( rotating ) delay (debounceDelay);
  if( digitalRead(encoderpinB) != B_set ) {
    B_set = !B_set;
    //  adjust counter - 1 if B leads A
    if( B_set && !A_set ) 
      encoderpos -= 1;

    rotating = false;
  }
}


void blink()
{
  state = !state;
  flag = HIGH;
}

thanks a ton buzztiaan!

superwelcome ;) (why didnt i spot this comment earlier?)