Arduino serail communication error, 36 integers from touchdesigner

Projects Networking, Protocols, and Devices
7

avoid using String class on a Mega which has low memory - it can fragment memory causing problems

read the text into a char array and parse it using sscanf(), e.g.

// parse comma seperated int data, e.g. 0,1,2,2,1,2,1

const int numValues = 36;       // 받을 정수의 개수
int receivedValues[numValues];  // 수신된 정수 배열을 저장할 배열
int index = 0;                  // 배열 인덱스 추적

void setup() {
  Serial.begin(115200);  // 시리얼 통신 속도 설정
}

void loop() {
  char data[100] = { 0 };
  if (Serial.available() > 0) {
    // read text into char array
    Serial.readBytesUntil('\n', data, 100);   
    Serial.println(data);
    char *ptr = data;   // point at start of text
    for (index = 0; index < 36; index++) {
      // attempt to read an integer - break if it fails
      if (sscanf(ptr, "%d", &receivedValues[index]) != 1) break;
      // find next , add 1
      ptr = strchr(ptr, ',') + 1;
      //Serial.println(receivedValues[index]);
      //Serial.println(ptr);
    }
    // display parsed data
    Serial.print("receivedValues ");
    for (int i = 0; i < index; i++) {
      Serial.print(' ');
      Serial.print(receivedValues[i]);
    }
  }
}

when " 0,1,2,2,1,2,1\n" is entered serial monitor displays

0,1,2,2,1,2,1
receivedValues  0 1 2 2 1 2 1

an alternative is to use strtok() function to break the text into tokens, e.g.

// parse string extracting numeric values to comma seperated list

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void setup() {
  Serial.begin(115200);
  char str[] = "0,1,2,2,1,2,1";
  char* pch;
  Serial.print("\nextracting numeric values from comma seperated list: ");
  Serial.println(str);
  pch = strtok(str, ",");
  while (pch != NULL) {
    //Serial.print ("token found ");
    //Serial.println(pch);
    int data;
    if (sscanf(pch, "%d", &data) == 1) {
      Serial.print("int value ");
      Serial.println(data);
    }
    pch = strtok(NULL, ":,");
  }
}

void loop() {}

serial monitor displays

extracting numeric values from comma seperated list: 0,1,2,2,1,2,1
int value 0
int value 1
int value 2
int value 2
int value 1
int value 2
int value 1