Change slotDuration of fullCalendar

I am using ui-calendar (witch based on fullCalendar) and default slot duration = '00: 30: 00 '. I want to change it to "00: 15: 00".

My config object:

  /* config object */
  $scope.uiConfig = {
    calendar:{
      height: 450,
      editable: true,
      duration: '00:15:00',
      slotDuration: '00:15:00',
      header:{
        left: 'title',
        center: '',
        right: 'today prev,next'
      },
      eventClick: $scope.alertOnEventClick,
      eventDrop: $scope.alertOnDrop,
      eventResize: $scope.alertOnResize
    }
  };

      

        
        
        
      

    

According to http://fullcalendar.io/docs/agenda/slotDuration/ . But that doesn't help :(