fread doesn't work

Hi, I tried to use fread with the little script in the 'help fread' in matlab, using my active COM but I get an error!

s = serial('COM3');
        fopen(s);
        fprintf(s, 'Curve?');
        data = fread(s, 512);

The error is:

Warning: Unsuccessful read: The specified amount of data was not returned within the Timeout period.

Answer 1

[David Sanchez]

You are trying to read data that are not available yet. Try with fscanf.