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From: Steve on 20 Jun 2010 23:00
> Please post your exact current code. I don't like guessing what you
> really have.

Ok, sorry for the effort!

s = serial('COM1');
s.BaudRate = 9600;
s.DataBits = 8;
s.StopBits = 1;
fopen(s);
data = fread(s, s.BytesAvailable, 'uint8');
fclose(s);
delete(s);

I always get a Timeout Message. Thanks for your help!
From: Walter Roberson on 20 Jun 2010 23:35
Steve wrote:

> s = serial('COM1');
> s.BaudRate = 9600;
> s.DataBits = 8;
> s.StopBits = 1;
> fopen(s);
> data = fread(s, s.BytesAvailable, 'uint8');
> fclose(s);
> delete(s);
>
> I always get a Timeout Message. Thanks for your help!

That arrangement is leaving things to chance: at best it reads the bytes
that happen to arrive in between the fopen() and the following fread()
call, since you do not pause() to give time for the bytes to transfer,
and you do not request to read to end of line with fgetl() or fscanf().

The first thing I would wonder would be what would happen if *no* bytes
had yet arrived. That would make s.BytesAvailable be 0, and the
documentation does not indicate what would happen in that case.
Returning immediately would be one valid behaviour (a more useful
behaviour in my opinion), but it would not be unknown for software to
treat a request to read 0 bytes as a request to read until the buffer
fills or you get a timeout.
From: Fly contact on 15 Jul 2010 10:18
You can start with that. Check the parameters with your hardware:

% Create the serial port object s associated with the COM1 serial
port.
s = serial('COM1');

% Configure property values
% parameters:
set(s,'BaudRate',28800); %-28.8k Baud rate
set(s,'DataBits',8); %default %-8 Data bits
set(s,'Parity','none'); %default value %-No Parity
set(s,'StopBits',1); %default %-1 Stop Bit
set(s,'Terminator','CR');
set(s,'FlowControl','hardware');

% Connect s to the instrument —
fopen(s);
% Identification Query.
fprintf(s,'ID?');
% exit
id = fscanf(s)
fclose(s);
delete(s);
clear s;

Good luck !*!
Sim
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