associate handels in matlab GUI

Hi I am Itamar and i have some problem while using MATLAB GUIDE.

I need to update multiple text boxes from UART Received data.
i created 'ByteAvailabeFcn' that interrupt when getting the configured num of bytes from the UART.
When i created the interrupted function that suppose to read the data and parse it to the text boxes i had a problem to set the handles of each text box.

does somebody know how to associate text box handles.

here is my example :

% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject handle to pushbutton1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
serial_port = serial('COM10','baudrate',115200);
set (serial_port,'DataBits',8);
set (serial_port,'ReadAsyncMode','continuous');
set (serial_port,'InputBufferSize',1);
set (serial_port,'BytesAvailableFcnMode','byte');
set (serial_port,'BytesAvailableFcnCount',1);
set(serial_port,'ByteOrder','littleEndian');%bigEndian
set (serial_port,'BytesAvailableFcn',@getData_4_gui_update2);
fopen(serial_port);

function getData_4_gui_update2(obj,event);
global serial_port;
ReceivedPacket = fread(serial_port,1);% read one byte from serial port
set(handles.edit1,'string',ReceivedPacket)
fclose (serial_port);
return
%fclose(instrfind);

function edit1_Callback(hObject, eventdata, handles)
% hObject handle to edit1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of edit1 as text
% str2double(get(hObject,'String')) returns contents of edit1 as a double
guidata(hObject, handles);

% --- Executes during object creation, after setting all properties.
function edit1_CreateFcn(hObject, eventdata, handles)
% hObject handle to edit1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
% See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
set(hObject,'BackgroundColor','white');
end

and the error i got:

??? Undefined variable "handles" or class "handles.edit1".


Thanks
Itamar