Get data from COM port

Hi everyone,

data is send to my laptop by a device through a usb port. How often the data is send depends on de sample time that i choose, it can vary from very 0.05s to ones very 30s.

i want matlab to get the data every time that the device sends it to my laptop. I am not that familiar with matlab and hope you can help me out a bit.

this is what i have so far...:

board = serial('COM3', 'BaudRate', 38400, 'DataBits',8);

fopen(board);

S = fscanf(board);

with S I get (I think) the oldest value stored in the input buffer every time i run fscanf

Thanks in advance!

Paul

Answer 1

[Walter Roberson]

Set a BytesAvailableFcn callback on the serial port object.

[paul kaam]

Could you perhaps explain this a little bit more? I have difficulty implementing this function.

many thanks

[Guillaume]

See the examples in the doc here and here. Basically, instead of asking the serial port for data, you wait for it to execute your function (callback) whenever data can be read.

[paul kaam]

Many thanks Guillaume!

Unfortunately i have a matlab version from my university and are not able to view the documents!! is it possible you send it to me?

with kind regards,

[Guillaume]

No, that would be a violiation of Mathworks copyright.

You can access the same documentation from within matlab by typing:

web(fullfile(docroot, 'matlab/matlab_external/bytesavailablefcn.html'))

and

web(fullfile(docroot, 'matlab/matlab_external/events-and-callbacks.html'))

[paul kaam]

many thank!