It seems that PLOT command is being bypass and not being execute..

 delete(instrfindall)
 clear all;clc
 s = serial('COM6');
 fopen(s) 
 A1 = 0; B1 = 0;
 for i = 1:1000
 P = fscanf(s,'%f')
 if P == 1
   A1 = A1+1; B1 = B1;
   elseif P == 2
   A1 = A1-1; B1 = B1;
 elseif P == 3
   A1 = A1; B1 = B1+1;
 elseif P == 4
    A1 = A1; B1 = B1-1; 
 else
 end
 plot(A1,B1,'*') 
 hold on
 end
 fclose(s) 
 delete(instrfindall)

I have written this code. I am receiving serially data very wel . But plot command is not being executed. As well * is not moving accordingly. Please correct me.

Answer 1

[Image Analyst]

A1 and B1 are just points, not vectors or arrays. So you will just see a single point, not a curve. To see it better, try this:

plot(A1, B1, 'b*', 'LineWidth', 2, 'MarkerSize', 30);
grid on;

If you want more points, then you need to make A1 and B1 vectors, or else put "hold on" and call plot over and over again with new values of A1 and B1.

[Nimisha]

I didn't want curve. I just want only single point.

But actual problem is that in my written code plot command is being bypass.

I am receiving continuous data from microcontroller serially. But its effect is not displayed on plot.

[Image Analyst]

So use the debugger. Put a break point early in the code and see where the code steps to, and then you'll discover why it's never getting to the plot() call. If you don't know how to use the debugger, see this: http://blogs.mathworks.com/videos/2012/07/03/debugging-in-matlab/

[Nimisha]

I run it step by step and it works fine. No problem.

But when I run it in continuous mode plot is not being generated. It seems that plot command is being bypass.

[Image Analyst]

Put in a drawnow

drawnow;

You might also put in a pause(0.5) if you want more time to view it.

[Walter Roberson]

Good point about the drawnow()

[Nimisha]

Thanks.

drawnow

Commmand works well to show and update plot.

Answer 2

[Walter Roberson]

After the

hold on

add

set(gca, 'xlimmode', 'auto', 'ylimmode', 'auto')

[Nimisha]

Ya. Thanks I modified my code with this command.

But my actual problem is mentioned above.