[Solved] Parsing serial data

Update:

I changed my code to parse it as it came in. So, here are my concerns.

The basic method already relied on the amount of time between receiving characters over serial to do it's business. (9600 baud) I am concerned that there is now so much to do that I will have issues later on. I will be implementing an Android app to connect through wifi to also make adjustments. As a possibility, because there are 2 cores, I could have one core listening to the wired serial and the other to wifi. I have never done that. I would also have to decide what operation should be interrupted to complete it's task.

So how much can happen between incoming characters before I would start seeing issues?

Here is my possible solution. It works and seems relatively simple. I will be adding functions to execute after this.

 while (Serial2.available()){
      char Smake = (char(Serial2.read()));
      if (String(Smake) != "#") {
        comms += String(Smake);
        if (String(Smake) != "*") {
          comms1 += String(Smake);
        }
        else {
          commParse[inputNumb] = comms1;
          comms1 = "";
          inputNumb = inputNumb + 1;
          }

      }
      else {
        commParse[inputNumb] = comms1;
        inputNumb = 0;
        comms = "";
        comms1 = "";
        commParse[5] = "NULL";
      }
	 }

@madmisha

Do you prefer to check and operate on each token on the fly, or store all of the tokens in an array first, and then perform the necessary operation on each token, according to what it is?

@frogandtoad I would prefer to sort all the tokens in the array first. My goal is to receive the data over serial and then manipulate the data. I might have the solution but I am still concerned about overloading the process and missing data. I am unsure if making the string(what I am using for debug readout of full message and to detect my stop character) and the string array. I guess I could just drop the string.

@madmisha

In the following example, I am simply printing each token directly from the serial stream:

// Test data: 1*72*1*5*2*1*SEND*

void setup() {
  Serial.begin(9600);
 }

void loop() {
  while(Serial.available() == 0); // Wait until data is sent...

  String token = Serial.readStringUntil('*');
  Serial.println(token);

  if(token == "SEND") {
    Serial.readStringUntil('\n'); // Remove any remaining junk...
    Serial.println("End of tokens... sending data!");
   }
 }

You can add each token to your array, then manipulate it as you wish.

Cheers!

@madmisha

Posted by: @madmisha

@frogandtoad I am receiving the data from a Nextion display and there is no function to send println that I know of. I could just include it in what I am sending but since it is working I think I will keep it the same. I am using a character instead. Seeing how simple your code is I might go back and see what I can do to make mine closer to your method. I like simple.

But you're reading from a com port, aren't you?
What is Serial2?

Posted by: @madmisha

But I do have a question about your method. Is it collecting the characters in the serial buffer in your example? It also looks like readStringUntil will clear it like flush. My understanding of the way I did it was that it would take each character as it is received and I would need to put it somewhere.

Yes, exactly... it is collecting the characters from the Serial buffer.  No, readStringUntil() will do exactly what it says 🙂  It will read all characters up to the delimiter you specify, and the next call eats everything up until the new line character.

Here is the reference: readstringuntil

If you do read from the serial buffer as per my example, then just add the token to your array - I just used println to display the output to the serial monitor so you can see it working.

Posted by: @frogandtoad

But you're reading from a com port, aren't you?
What is Serial2?

It is the second serial port on the ESP32 and where I have the screen connected to. It allows me to debug and send commands from my computer without interruptions to the screen communications. Just another reason I love my ESP32s. The instruction set for the Nextion does not have a println. I would have to add /n manually(that's how I I'm sending my stop character anyways). I see that I could easily change the example you provided to use my # character instead of new line.

I will be trying out both methods to see what I prefer and feel the safest with. Thanks for showing me another way of doing this!

@madmisha

Posted by: @frogandtoad

But you're reading from a com port, aren't you?
What is Serial2?

It is the second serial port on the ESP32 and where I have the screen connected to. It allows me to debug and send commands from my computer without interruptions to the screen communications.

Ok, I see... I had thought it was the second Arduino serial port, but just remembered that was Serial1 anyway.

Posted by: @madmisha

The instruction set for the Nextion does not have a println. I would have to add /n manually(that's how I I'm sending my stop character anyways). I see that I could easily change the example you provided to use my # character instead of new line.

 

I will be trying out both methods to see what I prefer and feel the safest with. Thanks for showing me another way of doing this!

No worries, let us know how you got on.

Cheers!