How can I use dsp.timescope in appdesigner to measure data from serial?

hi everyone, to simplify the problem I wrote a script of a few lines that makes the connection and reads data from a serial through a for loop and inside I inserted the plot through dsp.timescope.

My problem is why can't I see the waveform until the end of the for loop?

if I used a timer would I solve the problem?

The Matlab code I used is the following:

Fs=100;
scope = dsp.TimeScope(1,Fs,'TimeSpanSource','Auto', ...
    "TimeSpanOverrunAction",'Scroll', ...
    "ReduceUpdates",false, ...
    "AxesScaling","Updates", ...
    "ShowGrid",true);

arduinoObj = serialport("COM10",115200);
flush(arduinoObj);
arduinoObj.UserData = struct("Data",[],"Count",1)

show(scope)
release(scope);

for ll=1:20
    data = readline(arduinoObj);

% Convert the string data to numeric type and save it in the UserData
% property of the serialport object.
arduinoObj.UserData.Data(end+1) = str2double(data);

% Update the Count value of the serialport object.
arduinoObj.UserData.Count = arduinoObj.UserData.Count + 1;
%Plot in timescope
    signal = arduinoObj.UserData.Data';
    scope(signal);
    release(scope);
end

I used the following arduino code:

%%ARDUINO CODE %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// Create a variable to send
float number=0;
// Define Analog input Pin
const int analogInPin = A1;

void setup() {
  // initialize serial, use the same boudrate in Matlab command
  Serial.begin(115200);

}
void loop(){
  number = ((analogRead(analogInPin)*5)/1023)*sin(((float) millis()/1000)); // Give your float a value
  
  
  // Print terminator
  Serial.println(number);
  
  delay(200);
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Answer 1

[Khodour Al Kadry]

Hi Donato

By Looking at your code, I see that you are calling release in two unnessary spots. After show there is no need to call release. Inside the for loop as well I see that you are calling release which is not a good practice.

If the data coming from the arduino is not fixed size and for that reason you had to call release, I do recommned using dsp.AsyncBuffer ro buffer the data to the desired frame size, and then plot the data using the dsp.TimeScope object.

-Regards

Khodour