Matlab and Arduino serial data

I am sending a string data to Arduino from Matlab using the following code:

clear s;
s=serial('COM4','BAUD', 9600);  % Baud rate and COM port
fopen(s);
value1=('11,222;333<444>555?666');
display('data sent');
fprintf(s,'%s\n',value1);
fclose(s);

I am receiving and processing the string in Arduino using the following code:

    String command;
    int i;
    float data_rec;
    void setup() {
      // put your setup code here, to run once:
      command="11,222;333<444>555?666";
      Serial.begin(9600);
    }
    void loop() {
      if(Serial.available() >0){
        String command=Serial.readString();
        parseCommand(command);
        data_rec=Serial.parseInt();
        Serial.println("data_rec");
        Serial.println(data_rec);
      }
    }

    void parseCommand(String com){
      String F_d;
      String E_m;
      String L_p;
      String S_v;
      String H_d;
      String L_t;

      F_d=com.substring(0,com.indexOf(','));
      E_m=com.substring(com.indexOf(',')+1,com.indexOf(';'));
      L_p=com.substring(com.indexOf(';')+1,com.indexOf('<'));
      S_v=com.substring(com.indexOf('<')+1,com.indexOf('>'));
      H_d=com.substring(com.indexOf('>')+1,com.indexOf('?'));
      L_t=com.substring(com.indexOf('?')+1,com.length());

     Serial.println(com);
     Serial.println("F_d:");
     Serial.println(F_d);
     Serial.println("E_m:");
     Serial.println(E_m);
     Serial.println("L_p:");
     Serial.println(L_p);
     Serial.println("S_v:");
     Serial.println(S_v);
     Serial.println("H_d:");
     Serial.println(H_d);
     Serial.println("L_t:");
     Serial.println(L_t);
    }

This does not work with Matlab. However, when I send the same string from the Serial Monitor, it seems to work.

Why aren't I getting any output for the Matlab code? I am checking the data sent and received by Arduino over serial by monitoring the serial port using Serial Monitoring Studio.

Answer 1

[Nick]

Hi try adding a pause of a few seconds after you initialize the serial port. When you initialize the serial port on the Arduino, it resets the Arduino so you might be sending information before the Arduino is ready for it.

I added pause(2) and started to receive data back pause(1) still resulted in a timeout. You can check if there is data on buffer by using

s.BytesAvailable

and one way to read data back from the Arduino in Matlab is

fscanf(s)