Error with Callback

I am trying to use the GUI environment to obtain data from the serial port. Ideally I would like to have a serial config file serparate from my main file with the toggle button callback and everything, but that has been giving me trouble.

So I am trying to do the serial config whent eh toggle button is pressed. So far when I run the program, the program plots the data coming into the serial port just fine, however when I stop the program by pressing the toggle button, I get these errors:

Error in ==> TEST>togglebutton1_Callback at 122
          Out5(i) = fread(s);  

Error in ==> gui_mainfcn at 96
          feval(varargin{:});

Error in ==> TEST at 45    
          gui_mainfcn(gui_State, varargin{:});

Error in ==>
@(hObject,eventdata)TEST('togglebutton1_Callback',hObject,eventdata,guidata(hObject))

??? Error while evaluating uicontrol Callback

My filename is TEST...I'm not sure how to get around this. Am I going about this in the right way?

Any advice would be greatly appreciated!

Thank you

[Walter Roberson]

What actual error does it report? For example does it report that s is not open, or that it does not exist?

It is not clear why your stop routine would have an fread() ?

I think we are going to need code.