Questions tagged [eeprom]

Electronically Erasable ROM is a type of memory available on most boards. It is used for storing persistent data. Use the tag for questions about the EEPROM library or the hardware.

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229 views

How to write a float value EEPROM

I'm using this library for my DS3231 which have a Atmel 24C32 on it. i have a float value which increases by 0.5, like: 27.50 28 28.50 ... the code is like this: float lowTemp= 10.5 float ...
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1answer
213 views

esp8266 esp01s EEPROM and flashing

which flash option do I need to take to use EEPROM? Can I flash with 1MB and no SPIFFs and still write data to EEPROM? thanks T
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655 views

DS3231 and EEPROM

Currently to get time/date i'm using DS3231 module with the RTClib library, i want to use the Atmel 24C32 chip on the module to store some small values (temperature etc). Can i use the current ...
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1answer
51 views

Is it possible to execute a code in runtime when gets updated over the air (OTA)?

I would like to build a lib like ArduinoOTA but with no downtime at runtime. To achieve that I am wondering if it is possible to create a simple setup and loop code to Check for new releases If we ...
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0answers
145 views

Problem Writing/Reading EEPROM on MEGA

I want to make a program that writes on the EEPROM some structs, the final device will take structs of RGB LED data: typedef struct{ unsigned char r; unsigned char g; unsigned char b; } ...
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1answer
89 views

Best way of storing extra data for Arduino project

I am an arduino beginner and I am trying to make a speed camera alert system, it would start beeping if I am above the speed limit and getting close to the speed camera. There is this website where I ...
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1answer
385 views

How to upload and store settings/variables from computer on the arduino? [closed]

I'm literally as green of a noob as I can be at this moment. Been watching a ton of tuts as I plan my project, but can't seem to find anything about settings being uploaded from an external source, ...
2
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2answers
410 views

Write faster on AT24C32

I'm using AT24C32 EEPROM chip from ATmel. I found code that will write and read bytes from chip. Code writes and reads bytes correctly and without any problem. But I have to write few 8-byte values ...
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0answers
176 views

EEPROM.read data not comparing with DHT11 sensor value - Arduino temp controller

I'm using a DHT11 to read temperature to control a relay that will control a fan. When 'A' is pressed it allows the user to update the temp value that the relay will go HIGH at. The value is being ...
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2answers
2k views

Run code once after programming

I'm using EEPROM to store project settings non-volatile. After reuploading the sketch to my board (over SPI via ArduinoISP), the EEPROM is reset to full 0xFFs and I have to manually do a "software ...
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2answers
124 views

Store value in EEPROM to perform different actions on reset?

I want the same button to wake up (reset) and put it to sleep but this is hard if the button is tied directly to the rst pin. My thought was to read and store a value in EEPROM so tell the chip what ...
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1answer
143 views

What's going wrong with my EEPROM?

I've been chipping away at a project for a long time now and I've found a serious bug. Basically the user has an 8x8 grid, and each cell in this grid has a number of properties. I want to be able ...
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2answers
3k views

ESP8266 EEPROM seems not working, saved data are different when I try to read them

I'm working on project which require to save some data into the EEPROM. As I read online the ESP8266 has no real EEPROM, it use a section of FLASH just after the SPIFFS. Due to this read/write is ...
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3answers
2k views

Value of uninitialized EEPROM in ESP8266?

In my limited testing it appears that the EEPROM in the Wemos D1 is not initialized to 255 like the specs say is the case for AtMega based Arduinos. In fact, the values look to be more-or-less random. ...
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1answer
453 views

Why does my 16x2 LCD displays weird letters and can't insert key from keypad?

I'm a newbie on Arduino here, and this is my first project on 16x2 LCD, 4x4 keypad and others. So, the story is, after I uploaded the program for my group's Arduino alarm clock to the Arduino board, ...
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2answers
736 views

How to manage variable I2C read lengths requiring address incrementation (Wire/I2C/EEPROM IC emulation)

The question is about how to have information/control of a variable length read for an Arduino acting as a slave device. The concrete context is that I want to emulate an EEPROM IC. A byte write to ...
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2answers
573 views

Save Data before Shutdown

I am building a positioner and I store the current position to EEPROM when the move is complete. On start up, I want the positioner to return to the HOME position. I am running an UNO powered from the ...
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1answer
1k views

Adafruit Trinket M0 persistent storage?

I am using an Adafruit Trinket M0 to program a small game and would like to save the game state every so often. I am programming it through the Arduino IDE as the chip does not have enough space to ...
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1answer
557 views

EEPROM size limitation issue

I am creating a test program with Arduino Nano where I can save network and password. Here is my code to start with: void SaveNetwork(String ssid, String pass){ String com = ssid + "~" + pass; ...
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1answer
67 views

Writing and reading an ID to/from an Arduino reliably

I need a way to both ID (a sketch/compiled hex) and later on, identify based on this ID the project that got uploaded to my Arduino microcontroller. As of right now, I have explored multiple options ...
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1answer
2k views

Wemos D1 EEProm put/get not getting correct value

Hey all I have the following code in my Arduino IDE: #include <EEPROM.h> #include <ArduinoJson.h> bool debuggin = true; int brightness = 255; int ambientLight = 30; ...
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1answer
513 views

Device Security - EEPROM data [duplicate]

I'm writing code for Arduino that I plan to distribute. But I worry about piracy (the .HEX can extracted from the board and reuploaded to another). With that in mind, I am storing data to the EEPROM. ...
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3answers
2k views

Using EEPROM Anything in loop()

I'm trying to make a programm for Arduino Bluno Beetle, that saves a string in the loop. Here is my code: #include <EEPROM.h> #include <EEPROMAnything.h> struct config_t{ String ...
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1answer
303 views

How do I inherit a class that requires &foo() in its constructor?

General I have a library with a class constructor class Math(&foo1,&foo2);, which I would like to put into a library for class Algebra(), where foo1 and foo2 are defined in Algebra.cpp My ...
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1answer
246 views

How does Arduino memorize the last bytes from Bluetooth HC-05?

I have made a home automation project. Description: Light on, off through HC-05 Bluetooth module and my Android app. The problem is when the power is gone, the system stops, that's OK. After that, ...
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2answers
909 views

How can I declare global array with its length stored in EEPROM?

I am working with Arduino UNO connected with BV4612 display. I am working on a simple code that controls several water pumps. Each pump has several modes it can run in. I store these modes in an array....
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3answers
2k views

Is it possible to use extra AVR Flash memory as non-volatile EEPROM-like Flash memory storage?

In STM32 microcontrollers it is possible to use a technique that ST calls IAP, or In-Application Programming, in order to write to the Flash memory from your running application. They even have a nice ...
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1answer
2k views

string.indexOf() always returns a non-zero value

I am developing a hardware project which contains a facility to change the stored password by any user, if he/she knows the current password.The new password is stored in arduino eeprom. In the main ...
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3answers
585 views

Which EEPROM has a long lifecycle?

I would like to build a box counter for machine, so I'm going to use EEPROM in Arduino to save count. But the lifecycle is limited to 100,000 writes. Please suggest an external EEPROM with a long ...
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1answer
1k views

nodemcu EEPROM corrupting

Platform Hardware: [nodemcu amica ESP8266MOD] Core Version: [nodemcu-master-21-modules-2018-03-17-17-09-10] Development Env: [Arduino IDE|] Operating System: [Windows|...
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1answer
441 views

Write to EEPROM before shutdown

I'm currently designing a battery operated device that has to write data to an EEPROM before shutting down, or in regular intervals to save data. Would it damage the EEPROM if it had to shut down ...
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1answer
352 views

ArduinoJson buffer gets overwritten

I have not that much experience with native languages like c/c++ and I'm facing a strange issue, which drives me crazy. So I'm using an Wemos D1 mini (ESP8266) which uses a class calles ConfigManager ...
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0answers
702 views

ESP8266ex does not hold written EEPROM data, what could be wrong? [duplicate]

Solution: Need to call EEPROM.commit() after a write cycle. It is all about this board: It seems to be a NodeMCU V3, however there is no version 3 mentioned in the board list (also update board list)...
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3answers
1k views

Extending EEPROM life

I'm working on some software using an Uno (ATmega328P). I have a stage byte that can be 1 of 5 values (0-4) in my code and it will increase by 1 every 2.5 hours. If I lose power I need to ensure that ...
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1answer
506 views

Integer looping in EEPROM Read

I am reading data from a 24LC1025 over I2C with an Arduino and then outputing that data to my PC through the Serial interface. The EEPROM chip is seperated into two pages and at address 65535 [0x0FFFF]...
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1answer
501 views

Writing data to a specific address in EEPROM

I'm trying to write two strings to an Arduino Uno's EEPROM. Here, the first code block works fine: it writes string(True/False) at 'address 0'. But the second block, which writes data at 'address 5', ...
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1answer
519 views

Reading and comparing data from Arduino Uno EEPROM

I'm trying to read compare data from EEPROM (Arduino UNO). Reading is working fine but comparing it using the '==' operator is not working as expected. //string 'True' is already stored in EEPROM ...
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1answer
91 views

EEPROM - Arduino

In my recent project, I want to store values permanently. So for that, I want to use the EEPROM. I searched for it and read about it. Now, I have some questions. Questions: How many locations ...
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1answer
331 views

Object Sensor on conveyor belt (want to record the data in EEPROM for testing)

void setup () pinMode(trigPin, OUTPUT); pinMode(echoPin, INPUT); pinMode(LED_Blue_pin, OUTPUT); pinMode(LED_White_pin, OUTPUT); Serial.begin(9600); digitalWrite(LED_Blue_pin, LOW); digitalWrite(...
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1answer
49 views

how to check 24c32 eprom is connected or not to arduino runtime?

I want to check it on runtime if runitme i remove eprom then it shows "please insert dongle " also tried using while loop showing eroor.. How can i solve it? Wire.beginTransmission(80); error = ...
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1answer
796 views

How to read ASCII values from AT24C32 IC using Arduino? And what is serial.begin(?) in that EEPROM?

#include<Wire.h> #include<Eeprom24C32_64.h> #define EEPROM_ADDRESS 0x000 void setup() { Serial.begin(9600); eeprom.initialize(); const word address = 0x000; const byte count = 94; ...
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2answers
6k views

How to save a float variable to the eeprom

This is my first post here and I'm hoping there are some arduino hobbyists here to help me. Does anyone here know how to save a float variable directly to the eeprom? If so could have a look at the ...
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4answers
2k views

Read float and long from external EEPROM chip

I am using an Arduino to read information from an EEPROM chip over I2C with the code I found here: https://playground.arduino.cc/Code/I2CEEPROM It works great for int and char values but I also need ...
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1answer
216 views

MySensors GatewaySerial code not compiling [closed]

I am trying to compile GatewaySerial code from MySensors library for my Arduino Leonardo and it gives me EEPROM errors. Gateway code: /** * The MySensors Arduino library handles the wireless radio ...
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2answers
105 views

What values are the Atmel MCUs EEPROMs preloaded with?

I have checked with two datasheets: one for some ATMegas and one for some ATTinys MCUs and could not find what the EEPROM.get() call would read back if the EEPROM was empty (or contained default ...
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0answers
734 views

Set EEPROM to initial values when flashing ESP8266

I have a variable uint8_t a_ram which needs to be initialized from the EEPROM variable a_eeprom when the ESP boots up. Whenever a_ram changes, the new value has to be stored to the EEPROM (a_eeprom), ...
4
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1answer
8k views

How can configuration values be stored on an ESP8266?

I have a project that uses an MQTT service, and I'm wondering how to best store the configuration settings (server, user, password, port) for the service as right now they are just hard-coded into ...
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1answer
534 views

Reconnect to I2C with a different address (ATTiny85)

My project requires to reconnect to an I2C bus as a slave. I can't reset my ATTiny physically because I2C + my project + a pin to trigger the reset isn't possible due to the limited amount of pins ...
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2answers
1k views

does EEPROM.write() only writes changed data?

Do I understand the code in EEPROM.cpp / write() correctly, that val is only written to the EEPROM, if val differs from the current EEPROM contents at the given address? And if the answer is yes, ...
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1answer
955 views

Not sure why eeprom isn't reading back correctly

I'm new to saving data on eeprom and I'm obviously doing something wrong but I'm not sure what. I have one program which both writes to and reads the internal eeprom on a attiny85 and this seems to ...