MATLAB: How to open and close serial port in GUI based on flag

gui

I am trying to open and close port using handle.port_stt. It seems not to work for some reason. Also i can not open and close port multiple times.
Error using serial/fscanf (line 154)
    Unsuccessful read: OBJ must be connected to the hardware with FOPEN.*
    function open_port_btn_Callback(hObject, eventdata, handles)
        global myport;
        %----------------------Port opening-----------------------%
        %
        handles=guidata(hObject);
        if(~strcmp(handles.port_stt,'opened'))
        fopen(myport);
        handles.port_stt='opened';
        guidata(hObject,handles);
        end
        % --- Executes on button press in close_port_btn.
        function close_port_btn_Callback(hObject, eventdata, handles)
        global myport;
        %----------------------Port closing-----------------------%
        handles=guidata(hObject);
        if(~strcmp(handles.port_stt,'closed'))
        fclose(myport);
        handles.port_stt='closed';
        guidata(hObject,handles);
        end
        % --- Executes on button press in read_btn.
        function read_btn_Callback(hObject, eventdata, handles)
        global myport;
        handles=guidata(hObject);
            while(strcmp(handles.port_stt,'opened'))
                handles=guidata(hObject);
                x=fscanf(myport,'%f')/100
                pause(0.0001);
            end

Best Answer

You did an fopen(), but you do not know that it worked. You should check the Status property of the object, which will become 'open' upon success.
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