Problem with Callback Function / BytesAvailableFcn on GUI

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Yassin Kim
Yassin Kim 2015-7-5
评论： Walter Roberson 2015-7-8
i work since 3 days only on one thing ; to be able to receive continuously bytes from device (Arduino) on GUI programme but unfortunately i have not done. The Problem is that BytesAvailableFcn cannot be called.
function togglebutton1_Callback(hObject, eventdata, handles)
stat = get(hObject,'Value'); %returns toggle state of togglebutton1
if (stat == 1)
if ~isfield(handles, 'Ser')
set(hObject, 'String','Connected');
handles.Ser = serial('COM11','BaudRate', 9600);
handles.Ser.BytesAvailableFcnMode = 'Terminator';
set (handles.Ser,'RequestToSend','off');
set (handles.Ser,'Terminator','CR');
handles.Ser.BytesAvailableFcn = {@instrcallback,handles}; % Here the Problem!
fopen(handles.Ser) ;
end
elseif (stat == 0)
if isfield(handles, 'Ser')
fclose (handles.Ser);
handles = rmfield(handles, 'Ser');
end
end
guidata(hObject, handles)
function instrcallback(obj, eventdata, handles)
set(findobj('Tag','text2'),'String','Bytes Received!') ; % Test if that function works
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Yassin Kim
Yassin Kim 2015-7-6
Yes that's the Problem, i tried already :
get(handles.Ser,'BytesAvailableFcn')
and i got 0 I can receive Data with command
fscanf(handles.Ser)
in a loop while but i would like to use a callback function.
Yassin Kim
Yassin Kim 2015-7-6
编辑：Yassin Kim 2015-7-6
But if i use
Ser = serial('COM11','BaudRate', 9600);
Ser.BytesAvailableFcnMode = 'terminator';
Ser.BytesAvailableFcn = @instrcallback;
Ser.OutputEmptyFcn = @instrcallback;
set (Ser,'RequestToSend','off')
set (Ser,'Terminator','CR');
fopen(Ser) ;
in Command Window, i get
BytesAvailable event occurred at 18:38:36 for the object: Serial-COM11.
The Probleme is only with function instrcallback, it works when i delete it
%function instrcallback(obj, eventdata, handles)
%set(findobj('Tag','text2'),'String','Bytes Received!') ;

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回答（1 个）

Harsha Medikonda
Harsha Medikonda 2015-7-7
'instrcallback' accepts two parameters. Please refer to the following documentation link
instrcallback
Also,please refer to the following link for the usage of bytesavailablefcn
bytesavailablefcn
  1 个评论
Walter Roberson
Walter Roberson 2015-7-8
True, however it is only an error to specify more dummy parameters than actual arguments if one of the missing arguments is actually used.

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