Chapter 03 EEPROM

Project 03.1 EEPROM

Related Knowledge

EEPROM

The primary function of EEPROM (Electrically Erasable Programmable Read-Only Memory) is to enable non-volatile data storage, ensuring critical information remains preserved after power loss or system restart. In the ESP32 architecture, EEPROM is not a physical chip but a logical storage space emulated using a section of the internal Flash memory. Due to the limited erase-write cycles of Flash memory, frequent repeated write operations should be avoided in practical applications.

Component List

Freenove ESP32-S3 Display x 1

USB cable x1

Circuit

Connect Freenove ESP32-S3 Display to the computer with USB cable.

Sketch

Next, we download the code to Freenove ESP32-S3 Display to test Serial. Open “Sketch_03.1_EEPROM.ino” folder under “Freenove_ESP32_S3_Display_FNK0115\Sketches” and double-click “Sketch_03.1_EEPROM.ino”.

Sketch_03.1_Battery_Voltage

The following is the program code:

/*
* @ File:   Sketch_03.1_EEPROM.ino
* @ Author: [Eason Shen]
* @ Date:   [2026-07-03]
*/

#include "EEPROM.h"

#define EEPROM_SIZE 1
int addr = 0;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  EEPROM.begin(EEPROM_SIZE);
  int val = EEPROM.read(addr) + 1;
  delay(5);
  EEPROM.write(addr, val);
  EEPROM.commit();
  delay(1000);
  Serial.print("The data in EEPROM(0) is:");
  Serial.println(EEPROM.read(addr));
}

void loop() {
  // put your main code here, to run repeatedly:

}

Code Explanation

Include the header file required for EEPROM.

#include "EEPROM.h"

Define the EEPROM size as 1 byte.

#define EEPROM_SIZE 1

Set the baud rate to 115200.

Serial.begin(115200);

Allocate space for EEPROM.

EEPROM.begin(EEPROM_SIZE);

Read the value from address 0 of EEPROM.

int val = EEPROM.read(addr) + 1;

Write data to address 0 and commit the changes.

EEPROM.write(addr, val);
EEPROM.commit();

Click “Upload” to upload the code to Freenove ESP32-S3 Display.

This example demonstrates the function of saving data after power loss. Each time the device restarts, the counter will automatically increase by one.

Please note: This chapter does not involve the use of the screen. After the code for this chapter, the screen may not light up, which is normal and not a hardware malfunction. If you need to verify whether the screen is functioning properly, please refer to Chapter 10 for testing.