void checkInputs() {

  //encoder button
  if (!digitalRead(ENC_BTN_PIN) && !encPressRegistered) {
    encPressRegistered = true;
    encPressedTime = millis();
  } else if (digitalRead(ENC_BTN_PIN) && encPressRegistered) {
    encPressRegistered = false;
    encReleasedTime = millis();

    if (encReleasedTime - encPressedTime < 500) {  // press shorter than .5s is for entering the submenu
      if (insideTab == 0) {
        insideTab = 1;
      } 
      updateScreen();
    } else if (encReleasedTime - encPressedTime < 2000) {  // longer press (<2s) is for navigating back. longer than 2s presses are ignored
      if (insideTab == 1) {
        insideTab = 0;
        menuItem = 0;
      } 
      updateScreen();
    }
  }

  //encoder
  encoder.tick();
  int encPosition = encoder.getPosition();
  if (encPositionOld != encPosition) {
    int change = encPositionOld - encPosition;
    if (!insideTab && !shiftBtnPushed) { //Change tab
      displayTab = displayTab + change;
      if (displayTab > 100) { //to address "negative" numbers
        displayTab = 0;
      } else if (displayTab > 6) {
        displayTab = 6;
      }
    } else if (!insideTab && shiftBtnPushed && displayTab == 0 && masterClockMode == 0) { //Change BPM
      bpm = bpm + change;
      if (bpm > MAXBPM) {
        bpm = MAXBPM;
      } else if (bpm < MINBPM) {
        bpm = MINBPM;
      }
      calculateBPMTiming();
    } else if (!insideTab && shiftBtnPushed && displayTab != 0) { //Change Subdiv
      channels[displayTab - 1].subDiv = channels[displayTab - 1].subDiv - change;
      if (channels[displayTab - 1].subDiv > 200) { 
        channels[displayTab - 1].subDiv = 0;
      } else if (channels[displayTab - 1].subDiv > (sizeof(subDivs) / sizeof(byte)) - 1) {
        channels[displayTab - 1].subDiv = (sizeof(subDivs) / sizeof(byte)) - 1;
      }
      if (!isPlaying) {
        calculateCycles();
      }
    } else if (insideTab && !shiftBtnPushed) {
      menuItem = menuItem + change;
      if (menuItem > 100) { //for "negative" values 
        menuItem = 0;
      } else if (menuItem > lastMenuItem) { 
        menuItem = lastMenuItem;
      }
    } else if (insideTab && shiftBtnPushed && displayTab == 0 && menuItem == 0) { //Master Clock Mode
      masterClockMode = masterClockMode + change;
      if (masterClockMode > 100) {
        masterClockMode = 0;
      } else if (masterClockMode > 1) {
        masterClockMode = 1;
      }
    } else if (insideTab && shiftBtnPushed && displayTab == 0 && menuItem == 1) { //Modulation channel
      bpmModulationChannel = bpmModulationChannel + change;
      if (bpmModulationChannel == 0 || bpmModulationChannel == 1) {
        bpmModulationRange = 1;
      } else if (bpmModulationChannel > 100) {
        bpmModulationRange = 0;
        bpmModulationChannel = 255;
      } else if (bpmModulationChannel > 1) {
        bpmModulationChannel = 1;
      }
    } else if (insideTab && shiftBtnPushed && displayTab == 0 && menuItem == 2) { //Modulation range
      bpmModulationRange = bpmModulationRange + change;
      if (bpmModulationRange == 0) {
        bpmModulationRange = 1;
      } else if (bpmModulationRange > 100) {
        bpmModulationRange = 1;
      } else if (bpmModulationRange > 5) { //50bpm
        bpmModulationRange = 5;
      }
    } else if (insideTab && shiftBtnPushed && displayTab != 0 && menuItem == 0) { //Channel Mode
      channels[displayTab - 1].mode = channels[displayTab - 1].mode + change;
      if (channels[displayTab - 1].mode > 100) {
        channels[displayTab - 1].mode = 0;
      } else if (channels[displayTab - 1].mode > 2) {
        channels[displayTab - 1].mode = 2;
      }
    } else if (insideTab && shiftBtnPushed && displayTab != 0 && menuItem == 1 && channels[displayTab - 1].mode == 0) { //Offset
      channels[displayTab - 1].offset = channels[displayTab - 1].offset + change;
      if (channels[displayTab - 1].offset > 100) {
        channels[displayTab - 1].offset = 0;
      } else if (channels[displayTab - 1].offset > channelPulsesPerCycle[displayTab-1]) {
        channels[displayTab - 1].offset = channelPulsesPerCycle[displayTab-1];
      }
    } else if (insideTab && shiftBtnPushed && displayTab != 0 && menuItem == 1 && channels[displayTab - 1].mode == 1) { //RANDOM
      channels[displayTab - 1].random = channels[displayTab - 1].random + change;
      if (channels[displayTab - 1].random > 100) {
        channels[displayTab - 1].random = 0;
      } else if (channels[displayTab - 1].random > 9) {
        channels[displayTab - 1].random = 9;
      }
    } else if (insideTab && shiftBtnPushed && displayTab != 0 && menuItem == 2 && channels[displayTab - 1].mode == 0) { //CV1 for CLK
      channels[displayTab - 1].CV1Target = channels[displayTab - 1].CV1Target + change;
      if (channels[displayTab - 1].CV1Target > 100) {
        channels[displayTab - 1].CV1Target = 0;
      } else if (channels[displayTab - 1].CV1Target > 1) {
        channels[displayTab - 1].CV1Target = 1;
      }
    }
    else if (insideTab && shiftBtnPushed && displayTab != 0 && menuItem == 3 && channels[displayTab - 1].mode == 0) { //CV2 for CLK
      channels[displayTab - 1].CV2Target = channels[displayTab - 1].CV2Target + change;
      if (channels[displayTab - 1].CV2Target > 100) {
        channels[displayTab - 1].CV2Target = 0;
      } else if (channels[displayTab - 1].CV2Target > 1) {
        channels[displayTab - 1].CV2Target = 1;
      }
    } else if (insideTab && shiftBtnPushed && displayTab != 0 && menuItem == 2 && channels[displayTab - 1].mode == 1) { //CV1 for RND
      channels[displayTab - 1].CV1Target = channels[displayTab - 1].CV1Target + change;
      if (channels[displayTab - 1].CV1Target > 100) {
        channels[displayTab - 1].CV1Target = 0;
      } else if (channels[displayTab - 1].CV1Target > 2) {
        channels[displayTab - 1].CV1Target = 2;
      }
    }
    else if (insideTab && shiftBtnPushed && displayTab != 0 && menuItem == 3 && channels[displayTab - 1].mode == 1) { //CV2 for RND
      channels[displayTab - 1].CV2Target = channels[displayTab - 1].CV2Target + change;
      if (channels[displayTab - 1].CV2Target > 100) {
        channels[displayTab - 1].CV2Target = 0;
      } else if (channels[displayTab - 1].CV2Target > 2) {
        channels[displayTab - 1].CV2Target = 2;
      }
    }
    /* 

    } else if (displayTab != 0 && insideTab == 2) {  //modulation
      channels[displayTab - 1].modulationRange = channels[displayTab - 1].modulationRange + change;
      if (channels[displayTab - 1].modulationRange < 0 && channels[displayTab - 1].modulationChannel == 0) {
        channels[displayTab - 1].modulationRange = 0;
      } else if (channels[displayTab - 1].modulationRange > 6 && channels[displayTab - 1].modulationChannel == 0) {
        channels[displayTab - 1].modulationChannel = 1;
        channels[displayTab - 1].modulationRange = 0;
      } else if (channels[displayTab - 1].modulationRange < 0 && channels[displayTab - 1].modulationChannel == 1) {
        channels[displayTab - 1].modulationChannel = 0;
        channels[displayTab - 1].modulationRange = 6;
      } else if (channels[displayTab - 1].modulationRange > 6 && channels[displayTab - 1].modulationChannel == 1) {
        channels[displayTab - 1].modulationRange = 6;
      }

    } else if (displayTab != 0 && insideTab == 3) {  //offset
      channels[displayTab - 1].offset = channels[displayTab - 1].offset + change;
      if (channels[displayTab - 1].offset == 65535) {
        channels[displayTab - 1].offset = 0;
      } else if (channels[displayTab - 1].offset >= channelPulsesPerCycle[displayTab - 1]) {
        channels[displayTab - 1].offset = channelPulsesPerCycle[displayTab - 1];
      }
    } */
    updateScreen();
    encPositionOld = encPosition;
  }

  //play button
  if (!digitalRead(START_STOP_BTN_PIN) && !playBtnPushed) {
    if (masterClockMode == 0) {
      calculateBPMTiming();
      resetClocks();
      isPlaying = !isPlaying;
    }
    playBtnPushed = true;
    saveState();
    updateScreen();  //to wake up the screen if turned off
  } else if (digitalRead(START_STOP_BTN_PIN) && playBtnPushed) {
    playBtnPushed = false;
  }

  //shift button
  if (!digitalRead(SHIFT_BTN_PIN) && !shiftBtnPushed) {
    shiftBtnPushed = true;
    //display.fillRoundRect(120, 52, 8, 8, 3, SSD1306_WHITE);
    //display.display();
    updateScreen(); 
  } else if (digitalRead(SHIFT_BTN_PIN) && shiftBtnPushed) {
    shiftBtnPushed = false;
    //display.fillRoundRect(120, 52, 8, 8, 3, SSD1306_BLACK);
    //display.display();
    updateScreen(); 
  }

  //modulations
  a1Input = analogRead(ANALOGUE_INPUT_1_PIN);
  a2Input = analogRead(ANALOGUE_INPUT_2_PIN);
}