How to call function with BytesAvailableFcn?

How to call function with BytesAvailableFcn

I’m testing a serial loopback function using a COM bridge (COM5 and 6).

I want to write to COM5 and receive at COM 6. I would like to display the COM 6 data as soon it is ready.

I would like to use some sort of interrupt function to get the data ASAP.

Setting up the receiver serial object with:

set(S2, 'Terminator', 'CR'); 

set(S2, 'BytesAvailableFcnMode','Terminator');

set(S2, 'BytesAvailableFcn', @instrcallback);

This should call a function ”instrcallback” when CR is received!

My instrcallback function has only instrcallback(S2) as a input parameter and will not call this function.

? How do I declare my function properly?

Acc Mathworks helpsite “Events and Callbacks” they state the different event parameters to the callback function.

https://se.mathworks.com/help/matlab/matlab_external/events-and-callbacks.html#f75633

?How do I use them with respect to my task – all of them refer to a timestamp?

S1 = serial('COM5');                   % create serial object
set(S1, 'BaudRate',  9600);             % set BaudRate to 9600
set(S1, 'Parity', 'none');             % set Parity Bit to None
set(S1, 'DataBits', 8);                % set DataBits to 8
set(S1, 'StopBit', 1);                 % set StopBit to 1
set(S1, 'Terminator', 'CR');
set(S1, 'BytesAvailableFcnCount',10);
set(S1,'InputBufferSize',128);
set(S1,'OutputBufferSize',128);

fopen(S1);                             % open serial
%
%----------------------------------------------------------
% 
S2 = serial('COM6');                   % create serial object
set(S2, 'BaudRate',  9600);             % set BaudRate to 9600
set(S2, 'Parity', 'none');             % set Parity Bit to None
set(S2, 'DataBits', 8);                % set DataBits to 8
set(S2, 'StopBit', 1);                 % set StopBit to 1
set(S2, 'Terminator', 'CR');
set(S2,'InputBufferSize',128);
set(S2,'OutputBufferSize',128);
set(S2, 'BytesAvailableFcnCount',32);
set(S2, 'BytesAvailableFcnMode','Terminator');
set(S2, 'BytesAvailableFcn', @instrcallback);

fopen(S2);                             % open serial

Y=5;
z=1024;
out=1000;
a=1;

while Y~=0    %sending var z 5 times

     fprintf(S1,'%4.0f \n',z);            % send command to serial
       pause(0.2);                        % delay to wait for COM6 

z=z-1;
Y=Y-1;
%S2.BytesAvailable              % test that inputbuffer is incrementing OK
end

fclose(S1);
fclose(S2); 

%---------------------------------------------------------
%fCallback function ------------- display var z on screen 
function[]= instrcallback(S2)

out = fscanf(S2,'4.0%f');
disp('out')
  %fprintf('Test Var: %4.0f \r\n',out);

%flushinput(S2) test  

end 
% -----------

BR. Benjamin