Storing "String" data using EEPROM 'Write' or 'Put' command

Other Hardware Storage
1

I am new to this forum, so please forgive me if I am not following generally established norms on this forum.
I am stuck up on using EEPROM command 'Write' / 'Put' for referencing mobile number through which I received the SMS (i.e. number received through "sms.remoteNumber"). I want to store this mobile number using EEPROM 'Write' command for future use in the program. The intention is that even if my Arduino goes through power recycle, I can use stored number for sending other messages for future. I am using Uno & GSM shield in my project.
Has anybody programmed Uno for this kind of requirement? Appreciate if you can share the code or any help in this regard.

2

Hi

This is how I write strings to EEPROM:

#define E_MOBILE_330 3819

EPSW(E_MOBILE_330,"MOBILE");


void EPSW(int p_start_posn, char p_string[] ) { //EEPROMStringWrite
//Write a string to EEPROM and terminate it with a NULL
//We read first and do not rewrite bytes/chars that are unchanged

  for (int l_posn = 0; l_posn < (int) strlen(p_string); l_posn ++) {
	byte l_byte = (byte) p_string[l_posn];
	byte l_read = EEPROM.read(p_start_posn + l_posn);
	if (l_read != l_byte) {
	  EEPROM.write(p_start_posn + l_posn, l_byte);
	}
  }
  //write the NULL termination
  if (EEPROM.read(p_start_posn + strlen(p_string)) != 0)
	EEPROM.write(p_start_posn + strlen(p_string), 0);
  //
} //EPSW

This is writing the string "MOBILE" (which is the 330th string I have stored in EEPROM) into EEPROM starting at byte 3819.

I can retrieve the value associated with the define E_MOBILE_330 this way:

String l_mobile = EPSR(E_MOBILE_330);

String EPSR(int p_start_posn) { //EEPROMStringRead
//Read a NULL terminated string from EEPROM
//Only strings up to 128 bytes are supported
  byte l_byte;

  //Count first, reserve exact string length and then extract
  int l_posn = 0;
  while (true) {
	l_byte = EEPROM.read(p_start_posn + l_posn);
	if (l_byte == 0) {
	  break;
	}
	l_posn ++;
  }

  //Now extract the string
  String l_string = "";
  l_string.reserve(l_posn + 1);
  char l_char;
  l_posn = 0;
  while (true) {
	l_byte = EEPROM.read(p_start_posn + l_posn);
	if (l_byte == 0) {
	  break;
	}
	l_char = (char) l_byte;
	l_string += l_char;
	l_posn ++;
	if (l_posn == 128)
	  break;
	//
  }
  return l_string;
} //EPSR

I hope this helps.

Cheers

Catweazle NZ

3

Thanks Catweazle!!! I think, this should work for me as well. I will revert back after my try.

Cheers,
Lambodar

4

Hi

This is i have created for reading and writing string in EEPROM. i can able to read and write the values from EEPROM. here i am trying to store the values into one variable, but i can not able to store the values. Please help me , i am new for this .

#include <EEPROM.h>
void setup()
{
Serial.begin (9600);
char* siteid = "00000001 BTS001 BSC001 40 30";
byte len = (byte) strlen (siteid);
EEPROM.write(0, len);
for (int i = 0; i < len; i++)
{
EEPROM.write(1 + i, siteid );

  • }*
    }
    void loop()
    {
  • for (int i = 0; i < 8; i++)*
  • {*
  • char val=Serial.print ( (char)EEPROM.read(1 + i));*
  • }*
  • for (int i = 9; i < 15; i++)*
  • {*
  • char val2=Serial.print ( (char)EEPROM.read(1 + i));*
  • }*
  • for (int i = 17; i < 22; i++)*
  • {*
  • char val3=Serial.print ( (char)EEPROM.read(1 + i));*
  • }*
  • for (int i = 23; i < 25; i++)*
  • {*
  • char val4=Serial.print ( (char)EEPROM.read(1 + i));*
  • }*
  • for (int i = 26; i < 28; i++)*
  • {*
  • char val5=Serial.print ( (char)EEPROM.read(1 + i));*
  • }*
  • delay (500); *
    }
5

i can able to read and write the values from EEPROM.

OK. You should take a look at the functions EEPROM.put() and EEPROM.get() which are now part of EEPROM.h and can be used for multi byte write and read.

here i am trying to store the values into one variable, but i can not able to store the values

Can you please explain what you are trying to do, and how you plan to use the result.