function ft_realtime_sensysproxy(cfg)

% FT_REALTIME_SENSYSPROXY reads real-time continuous fluxgate magnetometer

% data from the serial interface provided by the Sensis FGM3D TD

% application and writes the data to the FieldTrip buffer.

%

% Use as

% ft_realtime_sensysproxy(cfg)

%

% The configuration should contain

% cfg.serialport = string, name of the serial port (default = 'COM2')

% cfg.blocksize = number, in seconds (default = 0.1)

% cfg.fsample = sampling frequency (default = 1000)

%

% The target to write the data to is configured as

% cfg.target.datafile = string, target destination for the data (default = 'buffer://localhost:1972')

% cfg.target.dataformat = string, default is determined automatic

%

% To stop this realtime function, you have to press Ctrl-C

%

% See also FT_REALTIME_SIGNALPROXY, FT_REALTIME_SIGNALVIEWER

% Copyright (C) 2023, Robert Oostenveld

%

% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org

% for the documentation and details.

%

% FieldTrip is free software: you can redistribute it and/or modify

% it under the terms of the GNU General Public License as published by

% the Free Software Foundation, either version 3 of the License, or

% (at your option) any later version.

%

% FieldTrip is distributed in the hope that it will be useful,

% but WITHOUT ANY WARRANTY; without even the implied warranty of

% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

% GNU General Public License for more details.

%

% You should have received a copy of the GNU General Public License

% along with FieldTrip. If not, see <http://www.gnu.org/licenses/>.

%

% $Id$

cfg = ft_checkconfig(cfg);

% set the defaults

cfg.serialport = ft_getopt(cfg, 'serialport', 'COM2');

cfg.baudrate = ft_getopt(cfg, 'baudrate', 921600);

cfg.blocksize = ft_getopt(cfg, 'blocksize', 0.1);

cfg.fsample = ft_getopt(cfg, 'fsample', 400);

cfg.target = ft_getopt(cfg, 'target');

cfg.target.datafile = ft_getopt(cfg.target, 'datafile', 'buffer://localhost:1972');

cfg.target.dataformat = ft_getopt(cfg.target, 'dataformat', []);

% these are not used at the moment, the defaults seem to work fine

cfg.databits = 8;

cfg.flowcontrol = 'none';

cfg.stopbits = 1;

cfg.parity = 'none';

% share the configuration details with the callback function

setappdata(0, 'cfg', cfg)

% the Sensys FGM3D TD Application allows serial data to be written out to a COM port

% open the serial device

sensys = serialport(cfg.serialport, cfg.baudrate);

%%

% this takes care of cleanup

cleanup = onCleanup(@()myCleanupFun(sensys));

% make sure the persistent variables are not reused from the last call

clear readSerialData

%%

% start the callback function, it processes each line

configureTerminator(sensys, "LF");

configureCallback(sensys, "terminator", @readSerialData);

% keep running forever, or until Ctrl-C

stopwatch = tic;

while (toc(stopwatch)<Inf) && strcmp(sensys.Status, 'open')

pause(0.1);

end

end % function

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% SUBFUNCTION

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function readSerialData(sensys, event)

% this is called on every line/sample that is received

% but the data is not written that fast, so we need a buffer

persistent buffer nchan blocksize counter

cfg = getappdata(0, 'cfg');

if isempty(buffer)

nchan = 5;

% ensure that each block is an integer number of samples

blocksize = round(cfg.blocksize*cfg.fsample);

buffer = zeros(nchan, blocksize);

counter = 0;

end

% The format is as follows:

% 1353411242214;0.0010416524;-0.0010926605;0.0014391395;0.0020856819<CR><LF>

%

% The separate values have the following meanings:

% Timestamp;Value Channel 1;Value Channel 2;Value Channel 3;Absolute Value<CR><LF>

line = char(readline(sensys));

line = strrep(line, ',', '.'); % depending on the language settings there might be a . or a , as decimal separator

dat = str2double(split(line, ';'));

buffer(:,rem(counter,blocksize)+1) = dat';

counter = counter + 1;

if counter==blocksize

% after the first block

hdr = [];

hdr.Fs = cfg.fsample;

hdr.nChans = nchan;

hdr.nSamples = counter;

hdr.nSamplesPre = 0;

hdr.label = {'timestamp', 'x', 'y', 'z', 'abs'};

% flush the file, write the header and subsequently write the data segment

ft_write_data(cfg.target.datafile, buffer, 'header', hdr, 'dataformat', cfg.target.dataformat, 'append', false);

fprintf('wrote header and %d channels, %d samples\n', nchan, counter);

elseif mod(counter,blocksize)==0

% after each subsequent block

% write the data segment

ft_write_data(cfg.target.datafile, buffer, 'append', true);

fprintf('wrote %d channels, %d samples\n', nchan, counter);

end % process complete block

end % function

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% SUBFUNCTION

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function myCleanupFun(sensys)

disp('cleanup');

configureCallback(sensys, "off");

disp('stopped')

clear sensys

clear readSerialData

end % function