UART = serial('COM15', 'BaudRate', 921600, 'StopBit', 2);
fopen(UART);
buf = [];

for c = 1:256
    A = fread(UART, 512, 'uint8');
    buf = cat(1, buf, A);
end

fclose(UART);
delete(UART);

marker = [hex2dec('01'), hex2dec('23'), hex2dec('45'), hex2dec('67'), hex2dec('89'), hex2dec('AB'), hex2dec('CD'), hex2dec('EF')];

B = reshape(buf, [1, 512 * 256]);
pos = strfind(B, marker);

header = B(pos(1):pos(1) + 11);

sample_size = header(10) * 256 * 256 + header(11) * 256 + header(12);
data_width = header(9);
sample_size_bytes = ceil(data_width / 8) * sample_size;
data_bytes = B(pos+12:pos+11+sample_size_bytes);

data = [];
for i = 1:sample_size
    data = cat(1, data, data_bytes(i * 2 - 1) * 256 + data_bytes(i * 2));
end
data = (data - mean(data));

F = fft(data);
P2 = abs(F);
semilogy((1:sample_size/2) * (50.0 / sample_size), P2(1:sample_size/2));
grid on