#define _CW 120
#define _CCW 180

uint8_t newByte = 0;
uint8_t lastByte = 0;
uint8_t checkByte = 0;
int16_t count = 0;

void setup() {

  Serial.begin(115200);
  DDRB = B00000000;

}

void loop() {

  newByte = PINB;

  if (newByte != lastByte) {
    checkByte = checkByte << 2 | newByte;
    lastByte = newByte;
    newByte = 0;
  }

  if (checkByte == _CW) { //0b 01 11 10 00
    count ++;
    Serial.print(" CW ");
    Serial.println(count);
    checkByte = 0;
  }
  
  if (checkByte == _CCW) { //0b 10 11 01 00
    count --;
    Serial.print("CCW ");
    Serial.println(count);
    checkByte = 0;
  }
}