How do you store and retrieve data from EEPROM on Arduino?

 To store and retrieve data from EEPROM on Arduino, you can use the built-in EEPROM library. This allows you to store data that persists even after power is lost.

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1. Include the EEPROM Library

cpp

#include <EEPROM.h>

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2. Writing Data to EEPROM

a. Write a Byte

cpp

EEPROM.write(address, value);  // value: 0–255

b. Write Any Data Type Using EEPROM.put()

cpp

int myValue = 123;
EEPROM.put(address, myValue);  // Handles any type (int, float, struct, etc.)

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3. Reading Data from EEPROM

a. Read a Byte

cpp

byte val = EEPROM.read(address);

b. Read Any Data Type Using EEPROM.get()

cpp

int myValue;
EEPROM.get(address, myValue);

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EEPROM Characteristics

• Limited write cycles (~100,000 per cell)

• Non-volatile (keeps data after reset/power off)

• Use EEPROM.update() instead of write() to avoid unnecessary writes.

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Example: Store and Retrieve an Integer

cpp

#include <EEPROM.h>

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

  int number = 42;

  // Store the integer
  EEPROM.put(0, number);

  // Read it back
  int storedNumber;
  EEPROM.get(0, storedNumber);

  Serial.print("Stored number: ");
  Serial.println(storedNumber);
}

void loop() {
  // Nothing here
}