ADC Serial print raw 16 bit binary. for MATLAB processing

ADC_from_Arduino.m

clc; close all; clear;

LIMIT = 500;
N_CHANNEL = 6;

% clear opened usb port
if ~isempty(instrfind)
  fclose(instrfind);
  delete(instrfind);
end

% open serial port sent by arduino
arduino = serial('COM36', 'BaudRate', 19200);

running = true;
is_start = false;
temp = -1;
current_channel = 1;
x = zeros(LIMIT+1, N_CHANNEL);
t = length(x);


timeout = tic;
delay_plot = tic;

fopen(arduino);
% loop read value from arduino
while running
  
  % if cannot read any signal in 6 seconds, stop the loop.
  if toc(timeout) > 6
    fprintf('timeout!!\n');
    break;
  end
  
  % read bytes everytime buffer has more than 40bytes
  if arduino.BytesAvailable > 40
    
    val = fread(arduino);
    
    % join the old value from previous iteration to array (val)
    if (temp >= 0)
      val = [temp;val];
      temp = -1;
    end
    
    % header detection; detect 0xABCD and deny all data before them.
    if (~is_start)
      index = strfind(val, [171,205]);
      
      % if header found cut ony data behind them
      if (~isempty(index))
        val = val(index(1)+2:end);
        is_start = true;
        fprintf('start!!\n');
        
        % play start sound
        [sound,sampling] = wavread('C:\\Users\\Chang\\Desktop\\Dropbox\\work\\chang emg 8ch\start');
        wavplay(sound(1:end),sampling*3) ;
      else
        continue;
      end
    end
    
    q=q+1;
    len = length(val);
    if mod(len, 2) == 1
      temp = val(end);
      val(end) = [];
      len = len - 1;
    end
    
    val = reshape(val, 2, len/2)';
    val = sum(val * [256;1], 2);
    % pre-addition
    if (current_channel ~= 1)
      x(end, current_channel:N_CHANNEL) = ...
        val(1:N_CHANNEL-current_channel+1);
      val = val(N_CHANNEL-current_channel+2:end);
      current_channel = 1;
    end
    
    len = length(val);
    i_end = mod(len, N_CHANNEL);
    end_val = val(end-i_end+1:end);
    val = val(1:end-i_end);
    
    % main-addition
    if x(1,:)==0
      x = reshape(val, N_CHANNEL, floor(len/N_CHANNEL))';
    end
    x = [x;reshape(val, N_CHANNEL, floor(len/N_CHANNEL))'];
    
    % post-addition
    if (i_end ~= 0)
      x = [x; ones(1, N_CHANNEL)*5555];
      x(end, 1:i_end) = end_val';
      current_channel = current_channel + i_end;
    end
    data=x;
    [size_dataM size_dataN]=size(data);
    
    if data(size_dataM,size_dataN)==5555
      data1=data;
      data = zeros(size_dataM-1,size_dataN);
      data=data1(1:size_dataM-1,:);
    end
    
    timeout = tic;
  end
end

% close serial port
fclose(arduino);
delete(arduino);
close all;

ADC_raw_16bit.ino

#define PIN_KEY 9
#define PIN_RESET 10
// Arrays to save our results in
unsigned long val,val1,val2,val3,val4,val5;
unsigned long time = 0;


// Define various ADC prescaler
const unsigned char PS_16 = (1 << ADPS2);
const unsigned char PS_32 = (1 << ADPS2) | (1 << ADPS0);
const unsigned char PS_64 = (1 << ADPS2) | (1 << ADPS1);
const unsigned char PS_128 = (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0);

// Setup the serial port and pin 2
void setup() {

  ADCSRA &= ~PS_128;
  ADCSRA |= PS_64;
  
  pinMode(A0, INPUT);
  pinMode(A1, INPUT);
  pinMode(A2, INPUT);
  pinMode(A3, INPUT);
  pinMode(A4, INPUT);
  pinMode(A5, INPUT);
  
  Serial.begin(19200);
  Serial.write(0xAB);
  Serial.write(0xCD);
}


void loop() {  
  val = analogRead(A0);
  val1 = analogRead(A1);
  val2 = analogRead(A2);
  val3 = analogRead(A3);
  val4 = analogRead(A4);
  val5 = analogRead(A5);

  Serial.write(val >> 8);
  Serial.write(val & 0xFF);
  
  Serial.write(val1 >> 8);
  Serial.write(val1 & 0xFF);
  
  Serial.write(val2 >> 8);
  Serial.write(val2 & 0xFF);
  
  Serial.write(val3 >> 8);
  Serial.write(val3 & 0xFF);
  
  Serial.write(val4 >> 8);
  Serial.write(val4 & 0xFF);
  
  Serial.write(val5 >> 8);
  Serial.write(val5 & 0xFF);
}