public ControlForm(PIC.PIC _pic)
        {
            InitializeComponent();
            this.pic = _pic;
            pic.registerExecutionStateListener(onPicExecutionChange);
            Disposed += delegate { pic.unregisterExecutionStateListener(onPicExecutionChange); };

            frequencyTextBox.Text = "4";
            frequencyUnitBox.SelectedIndex = 2;
        }