function ft_realtime_unicornproxy(cfg)

% FT_REALTIME_UNICORNPROXY reads continuous data from a Unicorn Hybrid Black

% wireless EEG system through Bluetooth and writes it to a FieldTrip buffer.

%

% The FieldTrip buffer is a network transparent server that allows the acquisition

% client to stream data to it. An analysis client can connect to read the data upon

% request. Multiple clients can connect simultaneously, each analyzing a specific

% aspect of the data concurrently.

%

% Use as

% ft_realtime_unicornproxy(cfg)

%

% The configuration should contain

% cfg.filename = string, name of the serial port (default = '/dev/tty.FireFly-B106-SPP')

% cfg.blocksize = number, in seconds (default = 0.2)

% cfg.writeeeg = 'yes' or 'no' (default = 'yes')

% cfg.writeaccel = 'yes' or 'no' (default = 'no')

% cfg.writegyro = 'yes' or 'no' (default = 'no')

% cfg.writebattery = 'yes' or 'no' (default = 'no')

% cfg.writecounter = 'yes' or 'no' (default = 'no')

%

% 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

%

% Prior to connecting the LED gives short flashes every second. After connecting it

% blinks on and off in a regular pace. When streaming the LED is constantly on.

%

% The Bluetooth protocol is documented in a PDF that is hosted on

% https://github.com/unicorn-bi/Unicorn-Suite-Hybrid-Black

%

% If you encounter Bluetooth connection problems on macOS, open a terminal and type

% sudo pkill bluetoothd

%

% See also FT_REALTIME_SIGNALPROXY, FT_REALTIME_SIGNALVIEWER

% Copyright (C) 2022, 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.filename = ft_getopt(cfg, 'filename', '/dev/tty.UN-20211209');

cfg.baudrate = ft_getopt(cfg, 'baudrate', 115200);

cfg.blocksize = ft_getopt(cfg, 'blocksize', 0.2);

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', []);

cfg.writeeeg = ft_getopt(cfg, 'writeeeg', 'yes');

cfg.writeaccel = ft_getopt(cfg, 'writeaccel', 'no');

cfg.writegyro = ft_getopt(cfg, 'writegyro', 'no');

cfg.writebattery = ft_getopt(cfg, 'writebattery', 'no');

cfg.writecounter = ft_getopt(cfg, 'writecounter', 'no');

% 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';

% ensure that each block is an integer number of samples

cfg.blocksize = round(cfg.blocksize*250)/250;

% share the configuration details with the callback function

setappdata(0, 'cfg', cfg)

% the unicorn uses the SPP protocol, i.e. serial-over-bluetooth

% open the serial device

unicorn = serialport(cfg.filename, cfg.baudrate);

%%

% this takes care of cleanup

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

%%

start_acq = hex2dec({'0x61' '0x7C' '0x87'})';

start_response = hex2dec({'0x00' '0x00' '0x00'})';

stop_acq = hex2dec({'0x63' '0x5C' '0xC5'})';

stop_response = hex2dec({'0x00' '0x00' '0x00'})';

start_sequence = hex2dec({'0xC0' '0x00'})';

stop_sequence = hex2dec({'0x0D' '0x0A'})';

%%

% start the data stream

write(unicorn, start_acq, 'uint8')

while unicorn.NumBytesAvailable<3

% wait for the expected response

end

response = read(unicorn, 3, 'uint8');

assert(isequal(response, start_response));

disp('started')

%%

% start the callback function, it processes each block of 45 bytes

configureCallback(unicorn, "byte", 45, @readSerialData);

% keep running forever, or until Ctrl-C

stopwatch = tic;

while (toc(stopwatch)<Inf)

pause(0.1);

end

end % function

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

% SUBFUNCTION

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

function readSerialData(unicorn, event)

% this is called on every sample

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

persistent buffer

cfg = getappdata(0, 'cfg');

% get a block of data

dat = uint8(read(unicorn, 45, 'uint8'));

% decipher the block of data

start = dat(1:2);

start_sequence = hex2dec({'0x0C0' '0x00'})';

assert(isequal(start, start_sequence))

% four bits

battery = bitand(dat(3), 0x0F);

battery = (100/15) * double(battery);

% big-endian, 24 bits

eeg = zeros(1,8);

for ch=1:8

offset = (ch-1)*3;

eeg1 = bitshift(uint32(dat(offset+4)), 16);

eeg2 = bitshift(uint32(dat(offset+5)), 8);

eeg3 = bitshift(uint32(dat(offset+6)), 0);

%bitget(eeg1, 32:-1:1)

%bitget(eeg2, 32:-1:1)

%bitget(eeg3, 32:-1:1)

eegv = bitor(bitor(eeg1, eeg2), eeg3);

if bitget(eegv, 24)

eegv = bitor(uint32(hex2dec('0xff000000')), eegv);

end

eegv = int32(eegv);

%bitget(eeg, 32:-1:1)

eeg(ch) = (4500000/50331642)*double(eegv);

end

% little-endian, 16 bits

accel = zeros(1,3);

for ch=1:3

offset = (ch-1)*2;

accel2 = bitshift(int16(dat(offset+28)), 0);

accel1 = bitshift(int16(dat(offset+29)), 8);

accelv = bitor(accel1, accel2);

accel(ch) = (1/4096)*double(accelv);

end

% little-endian, 16 bits

gyro = zeros(1,3);

for ch=1:3

offset = (ch-1)*2;

gyro1 = bitshift(int16(dat(offset+34)), 0);

gyro2 = bitshift(int16(dat(offset+35)), 8);

gyrov = bitor(gyro1, gyro2);

gyro(ch) = (1/32.8)*double(gyrov);

end

% little-endian, 32 bits

counter1 = bitshift(uint32(dat(40)), 0);

counter2 = bitshift(uint32(dat(41)), 8);

counter3 = bitshift(uint32(dat(42)), 16);

counter4 = bitshift(uint32(dat(43)), 24);

counter = double(bitor(counter1, bitor(counter2, bitor(counter3, counter4))));

% construct a representation that we can write to the FieldTrip buffer

dat = [];

hdr.Fs = 250;

hdr.label = {};

if istrue(cfg.writeeeg)

dat = cat(2, dat, eeg);

hdr.label = cat(2, hdr.label, {'EEG1' 'EEG2' 'EEG3' 'EEG4' 'EEG5' 'EEG6' 'EEG7' 'EEG8'});

end

if istrue(cfg.writeaccel)

dat = cat(2, dat, accel);

hdr.label = cat(2, hdr.label, {'AccelX' 'AccelY' 'AccelZ'});

end

if istrue(cfg.writegyro)

dat = cat(2, dat, accel);

hdr.label = cat(2, hdr.label, {'GyroX' 'GyroY' 'GyroZ'});

end

if istrue(cfg.writebattery)

dat = cat(2, dat, battery);

hdr.label = cat(2, hdr.label, {'Battery'});

end

if istrue(cfg.writecounter)

dat = cat(2, dat, counter);

hdr.label = cat(2, hdr.label, {'Counter'});

end

nchan = length(dat);

bufsize = 250*cfg.blocksize;

if counter==bufsize

% after the first block

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

elseif mod(counter,bufsize)==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 % if count==1

% (re)initialize the buffer

if isempty(buffer) || mod(counter,bufsize)==0 || size(buffer,1)~=nchan

buffer = zeros(nchan, bufsize);

end

% insert the data in the buffer

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

end % function

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

% SUBFUNCTION

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

function myCleanupFun(unicorn)

disp('cleanup');

configureCallback(unicorn, "off");

stop_acq = hex2dec({'0x63' '0x5C' '0xC5'})';

write(unicorn, stop_acq, 'uint8')

pause(0.1);

disp('stopped')

clear unicorn

clear readSerialData

end % function