Write and read data from EEPROM memory - NODEMCU

  #include <EEPROM.h>

#define EEPROM_SIZE 512

//EEPROM memory in NodeMCU is a kind of memory that does not delete any data even if

//the nodeMCU gets a reset of the power supply. Its like ROM

String myStr = "Hello";

void setup()

{

  Serial.begin(115200);

  EEPROM.begin(EEPROM_SIZE);

  Serial.println();

  writeString(70,"Kriya");

  writeString(140,"Item1,Item2,");

  Serial.println(read_String(70));

}

void loop()

{

 

}

void writeString(int add,String data)

{

  int _size = data.length();

  int i;

  for(i=0;i<_size;i++)

  {

    EEPROM.write(add+i,data[i]);

  }

  EEPROM.write(add+_size,'\0');   //Add termination null character for String Data

  EEPROM.commit();

}

String read_String(int add)

{

  int i;

  char data[100]; //Max 100 Bytes

  int len=0;

  unsigned char k;

  k=EEPROM.read(add);

  while(k != '\0' && len<500)   //Read until null character

  {    

    k=EEPROM.read(add+len);

    data[len]=k;

    len++;

  }

  data[len]='\0';

  return String(data);

}