how to plot digital data in sin graph in matlab

%run('clean');
clear all;
close all;

if ~isempty(instrfind)
fclose(instrfind);
delete(instrfind);
end

s = serial('COM5'); %assigns the object s to serial port
 
set(s, 'InputBufferSize', 256); %number of bytes in inout buffer
set(s, 'FlowControl', 'hardware');
set(s, 'BaudRate', 9600);
set(s, 'Parity', 'none');
set(s, 'DataBits', 8);
set(s, 'StopBit', 1);
set(s, 'Timeout',10);
set(s, 'Terminator', 'CR');
%clc;
 
disp(get(s,'Name'));
prop(1)=(get(s,'BaudRate'));
prop(2)=(get(s,'DataBits'));
prop(3)=(get(s, 'StopBit'));
prop(4)=(get(s, 'InputBufferSize'));
 
disp(['Port Setup Done!!',num2str(prop)]);
 
fopen(s);           %opens the serial port
t=0;
t_samp=0.1;
disp('Running');
x=0;
while(t<200)  %Runs for 200 cycles - if you cant see the symbol, it is "less than" sign. so while (t less than 200)
 
   a =fread(s); %reads the data from the serial port and stores it to the matrix a
   a=max(a);  % in this particular example, I'm plotting the maximum value of the 256B input buffer
 
   x =[x a];  % Merging the value to an array, this is not very computationaly effective, as the array size is dynamic.
                 %Consider pre allocation the size of the array to avoid this. But beware, You might loose some important
                  %data at the end!
   
   plot(x);
   axis auto;
   grid on;
 
   disp([num2str(t),'th iteration max= ',num2str(a)]);
   hold on;
   t=t+1;
   a=0;  %Clear the buffer
   drawnow;
end
 
fclose(s); %close the serial port

experiment = serial('COM2','BaudRate',9600,'Terminator','CR');
fopen(experiment)
Read_Data = fgets(experiment)
fclose(experiment)
delete(experiment)