Arduino and EEPROM

  EEPROM is a non-volatile memory on the Arduino. It's like a HDD in the computer, can hold the data when board is turned off, but has too little memory :(. The EEPROM size of Arduino Duemilanove's Atmega328 is only 1024 byte.
  Arduino IDE has simple EEPROM library, which has only 2 functions: "read" and "write". Lets write a demo program which will save to EEPROM anything received from serial port and if the 's' symbol is received it will return all stored symbols.

	#include <EEPROM.h> // include library
	int sz; // size of received data
	void setup()
	{
	Serial.begin(9600);
	sz = 0;
	}
	void loop()
	{
	if(0 < Serial.available())
	{
	int r = Serial.read();
	if ('s' == r) {
	Serial.println("\nYour history");
	for(int i=0; i<sz; ++i)
	Serial.print(EEPROM.read(i));
	Serial.println();
	}
	EEPROM.write(sz++, r);
	}
	delay(200);
	}

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