Matlab, Arduino Communication using BytesAvailableFcn Too many input arguments

Hey,

I'm having some Problems with the Serial Communication from Matlab to an Arduino.

It's supposed to be asynchronus read Operation (input from user) so I am using the 'BytesAvaiableFcn'.

Problem is I always get an Errormsg:

??? Error using ==>
mycallbacktest
Too many input arguments.

Error in ==> instrcb at 36
        feval(val{1}, obj,
        eventStruct,
        val{2:end});

Warning: The BytesAvailableFcn
is being disabled. To enable the
callback property
either connect to the hardware
with FOPEN or set the
BytesAvailableFcn property.

My Matlab code for initalizing the serial Port is:

s = serial('com5');
set(s, 'BaudRate', 38400,'InputBufferSize', 1024, 'OutputBufferSize', 1024,'timeout',100);
s.BytesAvailableFcnMode = 'byte';

s.BytesAvailableFcnCount = 3;

s.BytesAvailableFcn ={'mycallbacktest',s};

fopen(s);

pause;

To test my callback function I got this code

function [] = mycallbacktest(s)

ardudata = fscan(s);

%set buttons

butsym{1,1} = '!';

butsym{1,2} = '?';

if strcmp(ardudata(1),butsym{1,1})

     disp('case1')

elseif strcmp(ardudata(1),butsym{1,2})  

     disp('case2')    

else

      disp('case3') 

%     led_num = str2num(ardudata);

      pause(1)   

end

The Data from the Arduino:

case 1:

 !!!

case 2:

 ???

case 3:

 end of line char
 XXX

in case 3 I get a new line Char and in the next line a 3 digit number in the range from 001-090

Answer 1

[Sean de Wolski]

Using the string syntax for mycallback doesn't allow you to change the inputs. You'll probably want something like this

s.BytesAvailableFcn =@(~,~)mycallbacktest(s};

Now we ignore (~) the two default arguments given by every callback function (why you're getting the error), and pass in s, what your function needs.

[Elduderino]

Thank you very very mouch, working fine now