Esp32 eeprom size Feb 6, 2019 · ESP32 Arduino libraries emulate EEPROM using a sector (4 kilobytes) of flash memory. Sep 28, 2025 · 本文详细介绍了ESP32中EEPROM的使用方法，包括如何在不使用文件系统的情况下固化数据，如SSID、密码等，以及如何进行数据的读写操作。文章提供了代码示例，并强调了在多次写入数据时应注意的事项。 Nov 19, 2023 · ESP32 is no exception. Dec 2, 2016 · Does the ESP-WROOM-32 and/or the single ESP32 have an EEPROM to save settings, configurations and things like that? I am reading the Datasheet and I cannot find anything about it. 000. If you want to write data every few seconds to non-volatile memory, EEPROM is a much better choice. See the extra example May 5, 2024 · 最近更新于 2024-05-05 12:31 1 前言 在有些开发情景下需要使用 EEPROM，比如用于保存 WiFi 的 SSID 和 密码，且要求可以在程序运行中设置修改。 ESP32 并没有 EEPROM 硬件上的支持，但是提供了 API，可以在 FLASH 上模拟 EEPROM，默认大小为 4096 byte。 2 环境 2. Instead it emulates it using flash storage. So, if you’ve used the Arduino EEPROM before, this is not much different. h library as for Arduino with two differences. g. The ESP32 does not have an EEPROM as such. 2 软件 Arduino IDE 2. EEPROM is ok, but maybe not enough space. h> #include "EEPROM. If you use a uint8_t (unsigned short) to store your address, it will wrap Mar 28, 2019 · I made a partition to ESP32 to increase the size of program space and EEPROM size by reducing spiffs size, program space incremented, but EEPROM size is not changing. Feb 27, 2022 · 文章浏览阅读4. If Non-Volatile Storage Library [中文] Introduction Non-volatile storage (NVS) library is designed to store key-value pairs in flash. 36; // dummy value float Variable_2 = 10. With the ESP32 and the EEPROM library, you can use up to 512 bytes in flash memory. 1 esp32 2. The EEPROM is limited only by the size of your nvs partition, so you can easily store 2KB in there if you choose. The total flash memory size for most of the modules is 4MB, but some board will have 8MB or 16 MB Dec 7, 2021 · With these lines I was able to compile, upload and use a configuration that didn’t fit in the default, 4MB, scheme. Using the EEPROM put and EEPROM get functions, the software below illustrates how to read and write to EEPROM. read(0) - EEPROM. begin (size). h. Didn’t try to remove app1 partition to further increase available size, don’t know if it is used in OTA updates. Sep 18, 2021 · How to save and retrieve data from the ESP32 flash memory using the Arduino IDE. Is this normal? Im using the PUT & GET examples from here : https://docs. You can store bytes, integers, or other data types at specific addresses and retrieve them even after reboot. Fortunately, the memory on ESP32 can be extended with external flash/EEPROM, SD cards, and eMMC. The data held in the flash memory persists across resets or power failures. To write data to the flash memory, you use the EEPROM. commit () or board is reset? data is most probably lost. Mar 20, 2024 · Espressif ESP32 Official ForumWhile I completely agree with Sprite that Preferences is preferred (haha), there are shorthand functions in the EEPROM library to make it easier to deal with larger numbers. The other way around is to store it in JSON format, but how? SPIFFS maybe? Oct 13, 2019 · Learn how to use both internal and external EEPROM (Electrically Erasable Read-Only Memory) to provide nonvolatile storage for your Arduino projects. Using this library with the ESP32 is very similar to using it with the Arduino. How to fix that ? #include <EEPROM. Serial print gives me result = 1000. This is the first program I upload. Nov 22, 2017 · Hello, I just got my ESP32 dev board in the mail a few days ago, and I am trying it out with a few things. Its exceptional adaptability and … Jul 2, 2017 · Esp32 EEPROM is in flash. ESP32 is a powerful Wi-Fi development platform for building IoT applications of all sizes. SPIFFS got you confused? This article will provide everything you need to know to use SPIFFS for an ESP32 File System. commit(); I write more values to eeprom than this one value. begin(EEPROM_SIZE Jan 24, 2022 · Im using a LOLIN32 Lite board, and it seems that i lose stuff that's stored in the EEPROM every time i flash a new version of my code onto it. get () functions. Version “D” has a MIFA antenna. EEPROM (such as AT24C0X series) is a 1024-16384 bit serial electrically erasable memory (can also run in read-only mode by controlling pin levels), its storage space is generally distributed by word, with each word containing 8-bit space. The main practical differences between EEPROM and Flash is that EEPROM is slower, can be erased byte by byte, and has much higher write endurance. Jul 19, 2022 · Documentation for usage of the EEPROM library. i need know beyond the 1MB there is any eeprom available like 4mb or 8mb ? Mar 19, 2024 · 原文标题：ESP32 断电数据保存 EEPROM数据读取和写入 文章出处：【微信号：凌顺实验室，微信公众号：凌顺实验室】欢迎添加关注！ Aug 6, 2025 · Hi This is a testing code EEPROM can storage numbers from 0 to 255 ( A single byte has only 256 values, so can store 0 - 255) regardless EEPROM SIZE. write and EEPROM. I want to save some data to EEPROM, to retain that value even when the device is switched OFF. Save credentials, API keys, threshold values eeprom esp32, esp32 flash memoryMột hạn chế với bộ nhớ flash là số lần bạn có thể ghi dữ liệu vào nó. I bought an ESP32-WROOM-32 and i realize that there are some things who are not the same comparing to Arduino Nano,UNO or Mega. Do you need 4K? Can you split it? I suggest you have a look at the Preferences library. You do still have to keep track of how many bytes you are using so you can read/write to the correct addresses. It's an ESP32 WROOM 32 dev board, FCC ID: 2AC7Z-ESPWROOM32. write() function that accepts as arguments Apr 8, 2022 · So, for quite some time I have been trying to check and test EEPROM, and actual storage I may get with it. Nov 4, 2023 · The same code, namely #include <EEPROM. Introduction The Preferences library is unique to arduino-esp32. EEPROM is a memory whose values are kept when the board is powered off. To answer the question: First, you should call EEPROM. The entire space is split between bootloader, application, OTA data, NVS, SPIFFS, and EEPROM. It's pretty nice ;) Jan 2, 2023 · I need to store some data in ESP32. read (0), does not work on a Nano ESP32. You can also persist data using the filesystem if you want. But if I change #define EEPROM_SIZE to, say 10, the sketch crashes after uploading. ESP32 EEPROM Size Despite the fact that the ESP32 EEPROM library is using the FLASH memory on-board which is 4MB in size, the ESP32 EEPROM allowable size is 20kB “ theoretically “. The ESP32 series employs either a Tensilica Xtensa LX6, Xtensa LX7 or a RiscV processor, and both dual-core and single-core variations are available. One of the things that i realized who are diferent is how to store and read data from the controler. My apologies, I'm using an Arduino Nano ESP32. Jan 29, 2023 · I write to eeprom: #define EEPROM_SIZE 15 EEPROM. cat under Code, Tutorial and tagged arduino, eeprom, esp32, esp8266, memory, memory layout, meory partitions, ota, rotation, spi flash memory. Aug 5, 2025 · Take a look at the EEPROM. Two things are confusing me here: If the #define EEPROM_SIZE 2 means 2 bytes, how come I can write 5 integers into the vitual May 3, 2021 · Code with the EEPROM library To interface with the EEPROM of the ESP32, we can use the EEPROM. Dec 30, 2020 · I'm trying to write some values to the EEPROM on an esp32 but I just get zeros after reboot up. You can find the exact layout in the following partition Arduino core for the ESP32. So is SPIFFS. ard… ESP32 is a series of low cost, low power system on a chip microcontrollers with integrated Wi-Fi and dual-mode Bluetooth. Some EEPROM libraries, like on the ESP32 and ESP8266, require EEPROM. So it is written in RAM, until a eeprom. //first upload #include <Arduino. If you reset or power off the Arduino, the data stored disappears. commit () calls. The application can choose to use the Feb 20, 2023 · 这意味着使用 ESP32 和 EEPROM 库可以有 512 个不同的地址，可以在每个地址位置保存一个 0 到 255 之间的值。 简单来说EEPROM里面的数据是可以断电保存的，重新上电数据并不会丢失。 Jun 4, 2018 · "EEPROM Rotation for ESP8266 and ESP32" was first posted on 04 June 2018 by Xose Pérez on tinkerman. If so, what's the size? Many thanks Jul 18, 2021 · hi . Jan 12, 2022 · Re: ESP32 memory size advice Postby Sprite » Thu Jan 13, 2022 1:16 am ESP32 ROM is actual read only memory, as in: it's programmed in the chip design phase and you can't change it. Which is already not really what the board was supposed to ESP32-WROOM-32D / ESP32-WROOM-32U ¶ Both modules have ESP32-D0WD chip on board of a smaller footprint than ESP32-D0WDQ6 installed in ESP32-WROOM-32. Before using the function, we have to initialize the size of the memory with begin () and the update function does not exist but the write function has the same function as update. Developers can either connect peripherals with jumper wires or mount ESP32-DevKitM-1 on a breadboard. Mar 28, 2019 · I made a partition to ESP32 to increase the size of program space and EEPROM size by reducing spiffs size, program space incremented, but EEPROM size is not changing. It includes in-built antenna switches, RF balun, power amplifier, low-noise receive amplifier, filters, and power management May 13, 2021 · How did you arrive that that number and what is the maximum EEPROM size on the ESP32 ? ESP32-DevKitM-1 [中文] The ESP32-DevKitM-1 is a ESP32-MINI-1-based development board produced by Espressif. 000 hoạt động ghi. This gives you 512 addresses, and at each address resides a value that is a number between 0-255. Mar 18, 2021 · This article will explain what an EEPROM is and provide a brief overview of the other memories available in a microcontroller. 0. Nov 21, 2023 · EEPROM library on ESP32 uses the NVS as backend, which limits the size to a bit under 2KB. Now I read eeprom: EEPROM. begin() at the start of the program. h>, and then EEPROM. If you call EEPROM. put(4, item_inside. 2. Oct 10, 2021 · Beginner in Arduino and ESP-32 needs help. begin() and EEPROM. The total flash memory size is (for most of the mass produced modules) 4MB, although some are produced with 8 or 16 MB. I have added the initialization sequence Feb 7, 2024 · Hey all, Working on a project with an esp32(wroom) and I need to store some data that will be entered during the program. This article will give more in-depth information about ESP32 Flash memory and using the EEPROM library to read and write any data type to the ESP32 Flash memory. Wikipedia says that this type of board has 4 MiB of flash memory. This section introduces some concepts used by NVS. This data is retained across restarts and loss of power events to the system. Preferences works best for storing many small values, rather than a few large values. What happens if program crashes before eeprom. read(4). Aug 31, 2017 · We have a similar tutorial for the ESP32: ESP32 Flash Memory – Store Permanent Data (Write and Read) Introduction When you define and use a variable, the generated data within a sketch only lasts as long as the Arduino is on. 36; //Dummy value int Eaddress = 0; boolean Sep 2, 2018 · Hello, I am porting a SW from ATMega to ESP32 and have some difficulties with the EEPROM as apparently nothing is stored. 13 Likes Can't use full 8MB flash on ESP32S3 RGB565 support Change framework to esp-idf UniKyrn Aug 21, 2020 · EEPROM. You”ll also learn how to use EEPROM in Arduino and ESP microcontrollers (ESP8266 and ESP32). One thing that baffles me is that it apparently doesn't have 16 megabyte of flash memory as advertised. You set the size when you call EEPROM. The library uses all the partitions with data type and nvs subtype. Same thing applies to SSD. Both of these seem to work fine for integer variable, However, EEPROM. Underlying Storage Currently, NVS uses a portion of main flash memory through the esp_partition API. Note that the ESP32 EEPROM library emulates the EEPROM in flash memory and requires to call EEPROM. 7k次，点赞2次，收藏30次。今天我们来玩儿EEPROM。EEPROM概述 ESP32内部没有专门的EEPROM，但是我们可以通过FLASH模拟EEPROM，FLASH与EEPROM也是非常相似的，都是非易失性存储器，_老宇哥带你玩转esp32 Jan 8, 2020 · The size of the array is count of items multiplied by the size of the item. println(KORTHORN_EEPROM_INT); EEPROM. put. begin(EEPROM_SIZE); int KORTHORN_EEPROM_INT = KORTHORN_EEPROM. Some places I read say it doesn't even have eeprom, others say its depreciated. Apr 16, 2020 · From EEPROM maximum size - ESP32 Forum ESP32 Arduino libraries emulate EEPROM using a sector (4 kilobytes) of flash memory. It seems to work fine. However, the developers of the ESP32 Core for Arduino included an EEPROM library that emulates the behavior to make it easy to use. They allow you to save and load variables of any type and size but it is up to you to space the storage locations apart so that saving one value does not overwrite a previously saved value Employing the EEPROM library with the ESP32, one can work with a total of 512 bytes of flash memory. By default the module has 4MB flash and may be also ordered with custom flash size of 8 or 16MB, see Espressif Products Ordering Information. Whenever the ESP32_RTC_EEPROM wakes up with an empty RTC RAM (which is detects by the presence of a magic word), it will try to see if there's a saved copy of the right size. The EEPROM library for the ESP32 is deprecated; new code should use the Preferences library. The ESP32 microcontroller has a Flash memory area that can be interfaced with Arduino EEPROM libraries using a sector (4 kilobytes) of flash memory. toNVS(), a copy of your EEPROM data will be save to the key "eeprom" in NVS flash, exactly like when you would use the original EEPROM. This stores Oct 26, 2023 · Writing Data to EEPROM in ESP32 Introduction The ESP32 microcontroller is an innovative star in the rapidly growing field of IoT devices and smart technologies. Do I need to specify the size of the variable somehow? van_der_decken March 15, 2024, 9:54pm 6 mfusco: Apr 14, 2020 · EEPROM Library To read and write from the ESP32 flash memory using Arduino IDE, we’ll be using the EEPROM library. 1 硬件 ESP32-WROOM-32 2. write (0, 5) writes 5 at address 0 on an emulated eeprom. get did not work Also, can someone help me understand when should I use EEPROM. h> //#define EEPROM_SIZE 2 #defi… Jul 6, 2023 · ESP32 doesn't have EEPROM. The total flash memory size for most of the modules is 4MB, but some board will have 8MB or 16 MB The EEPROM library allows reading and writing data to flash memory. h library. Most of the I/O pins are broken out to the pin headers on both sides for easy interfacing. Oct 10, 2021 · The first thing to know is that, unlike Arduino, the ESP32 doesn't have an EEPROM. . If so, what's the size? Many thanks Dec 2, 2016 · Does the ESP-WROOM-32 and/or the single ESP32 have an EEPROM to save settings, configurations and things like that? I am reading the Datasheet and I cannot find anything about it. SPIFFS moves writes around to level the wear, EEPROM library doesn’t. It uses a portion of the on-board non-volatile memory (NVS) of the ESP32 to store data. ESP32 chips are paired with flash chips (which are e. there is market available 24c1024 is 1MB data size . I'm not sure what to make of it? So I thought I'd just outline what I need to store and let yall recommend the best Mar 15, 2024 · And you didn't mention what processor this is running on. write(3, KORTHORN_EEPROM_INT); EEPROM. MEMORY USED IN MICROCONTROLLER There are various types of Nov 6, 2018 · Learn how to use the ESP32 flash memory to store permanent data. Mar 2, 2021 · Save data permanently on the ESP32 flash memory using Preferences. commit () comes. Though I have used eeprom before on arduinos, I'm a bit confused on the esp32. I've added a simple little boot up routine so it only outputs the data once on the serial monitor. read and EEPROM. It should be considered as the replacement for the Arduino EEPROM library. AFAICT, all the write methods have bounds checking, so I suspect the issue is in your code, which you have not provided. So: #define EEPROM_SIZE Jan 17, 2024 · As far as I understand, eeprom. Unlike traditional EEPROM, the ESP32 emulates EEPROM Jun 16, 2022 · The quote above is incorrect. write does not compile with string as it expects integer. h" float Variable_1 = 12. Trying to look into my ESP32's datasheet was no help, so naturally I googled for answers for the maximum size I c… Sep 12, 2022 · I have sketch for the ESP32 which has the line #define EEPROM_SIZE 2 and later reads (or writes) one or two digit integers into EEPROM. I have the following code Jun 1, 2019 · Using ESP32’s Flash Memory for data storage The ESP32 has about 4MB of internal flash memory and since the data stored within the flash memory is retained even when power is recycled, it becomes super useful for applications where you need to keep certain amount of data even after power off. Hope it helps someone, since I didn’t find any info on this. Contribute to espressif/arduino-esp32 development by creating an account on GitHub. serial); enter image description here As you can see both functions, EEPROM. The external flash chips or EEPROM are suitable when a small increment in storage capacity is required. If you want to keep the data stored for future use you need to use the Arduino EEPROM. Dữ liệu có thể được đọc từ flash bao nhiêu lần tùy thích, nhưng hầu hết các thiết bị được thiết kế cho khoảng 100. toInt(); Serial. KORTHORN_EEPROM = 1000 and is coming from JSON. SD has the same problem with wear, and the same solution: wear leveling. So, we also recommend taking a look at our article about Arduino EEPROM. Mar 3, 2023 · Store Permanent Data using EEPROM What is EEPROM? The EEPROM is an internal memory of the ESP32 microcontroller that allows to keep in memory data after restarting the board. commit(). write (0, messageNumber); and later messageNumber = EEPROM. put () and EEPROM. 000 đến 1. 4 megabytes) and your sketch lives in a partition on that chip. 14 Jun 19, 2024 · Learn how to use EEPROM, short for electrically erasable programmable read-only memory, on Arduino boards. begin (size) and EEPROM.