Arduino UNO R4 Minima EEPROM

Learn how to access the EEPROM memory on the UNO R4 Minima.

In this tutorial you will learn how to access the EEPROM (memory) on an Arduino UNO R4 Minima board. The EEPROM is embedded in the UNO R4 Minima's microcontroller (RA4M1).


The goals of this tutorials are:

  • Write to the EEPROM memory,
  • Read from the EEPROM memory.

Hardware & Software Needed


Electronically erasable programmable read-only memory (EEPROM) is a memory that can be used to store data that can be retrieved after power loss. This memory can be effective to use during run-time to log data that can be used to re-initialize whenever a system comes back online.

The Arduino Uno R4 Minima has 8 kB of EEPROM.

When writing to the EEPROM memory, we specify two parameters: the address and value. Each byte can hold a value between 0-255.

1EEPROM.write(0,15); //writes the value 15 to the first byte

We are writing a value of

to the first byte available in the memory,

To read the value of this memory, we simply use:; //reads first byte

There are several more methods available when working with EEPROM, and you can read more about this in the A Guide to EEPROM.

Please note: EEPROM is a type of memory with limited amount of write cycles. Be cautious when writing to this memory as you may significantly reduce the lifespan of this memory.


A minimal example on how to write to the EEPROM can be found below:

1#include <EEPROM.h>
3int addr = 0;
4byte value = 100;
6void setup() {
7 EEPROM.write(addr, val);
9void loop(){


A minimal example on how to read from the EEPROM can be found below:

1#include <EEPROM.h>
3int addr = 0;
4byte value;
6void setup() {
7 Serial.begin(9600);
8 value =;
9 while (!Serial) {
11 }
13 Serial.print("Address 0: ");
14 Serial.println(addr);
17void loop() {


In this tutorial, you've learned how to access the EEPROM on the UNO R4 Minima board. To learn more about EEPROM, visit A Guide to EEPROM.

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