How to connect to the bluetooth Serial Port?

I am trying to use the SSP as a COM port to receive data from MCU. I have to try many times to connect to the COM port, but it often failed to open.The version is R2013a and the codes are as below:

s=serial('COM4');

fopen(s);

Sometimes it would work,but usually failed and get errors:

Open failed: Port: COM4 is not available. Available ports: COM4, COM5. Use INSTRFIND to determine if other instrument objects are connected to the requested device.

Sometime I get this:

Open failed: Cannot connect to the COM4 port. Possible reasons are another application is connected to the port or the port does not exist.

I use instrhwinfo('serial') to check whether the COM4 is available, and I could find the COM4 is in AvailableSerialPorts list.Even when the COM4 is not in AvailableSerialPorts list, sometimes I can still connect. I was so confused.

Here describe a similar problem, but I can't get any data using data=fgets(b);

http://cn.mathworks.com/matlabcentral/answers/32504-how-to-connect-matlab-with-bluetooth-hc-05

What's more I need to configure the COM ports like BaudRate,DataBits,StopBits.....But I can't find these properties in bluetooth!

Answer 1

[Mark O'Sullivan]

This may be because you're not closing the serial connection after using it. After you open a serial connection and read from it, you need to close it before you can open and read from it again.

So something like this should work every time:

s=serial('COM4');
fopen(s);
fgets(s);
fclose(s);

If you have an error and your script stops before reaching the fclose line, then you can use the following 2 commands to clear the open serial ports.

newobjs = instrfind;
fclose(newobjs)

That should fix that problem. :)

[María Itzel Marroquín Ram]

hi, im 3 years late and you should have solved this issue by now, but i found this for if you or anyone else needs it again

https://www.mathworks.com/matlabcentral/answers/10027-matlab-serial-communication-via-bluetooth-spp