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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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String or unsigned char to uint8_t

I'm attempting to save a string to EEPROM of an ESP8266 radio and then read it back before I encrypt the data (evenutally I would like to save the encrypted data but I'm simplifing things at the ...
PhippsTech's user avatar
0 votes
1 answer
102 views

Problem saving "char" variable to EEPROM on ESP32

I am making a project, in which I need to store the WiFi credentials to the EEPROM. For now, I am able to store a bool array in the EEPROM, but I am not able to store the char variables as the ESP32 ...
Loic Daigle's user avatar
-3 votes
1 answer
416 views

Is the EEPROM the best alternative for store non-volatile values with Arduino?

SD-cards are capable of store values even if it is turned off. I don't know what is the time that a EEPROM can keep a value in it's memory, but of course are better than the volatile memory. There are ...
Guilherme's user avatar
3 votes
1 answer
135 views

changing a single bit in an arduino EEPROM byte

In my code I have a number of boolean flags that tell me if data has been written to specific places in the EEPROM. I need to save these flags to the EEPROM and recover them on a restart. Is the ...
BRUCE DURANT's user avatar
0 votes
2 answers
248 views

How EEMEM maps the variables? (avr/eeprom.h)

I can store and restore my data with avr/eeprom.h if I don't change the sketch. I have a sketch that stores the data. After power cycle of the device the data are fine. If I change the sketch with ...
krg's user avatar
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-1 votes
1 answer
26 views

manage some output based on some parameter and rtc

i'm trying to create a program that given a configuration (i've used multiple struct nested) i need in loop() to check for each output if they need to be on or off and set the output accordingly let ...
Darkmagister's user avatar
1 vote
0 answers
77 views

Attiny84 with external eeprom-write and read beyond 255

Just starting with external EEPROM and ATTiny's. I am successfully writing and reading to the 24LC64 chip using the following code with TinyWireM (thanks to other help on the forums). However, I ...
VinnyP's user avatar
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1 vote
2 answers
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Bitwise Operator in Arduino Code Question

What is the below Arduino code doing? I am not familiar with the '+' with regard to bitwise operations. Just getting familiar with this stuff. return ((four << 0) & 0xFF) + ((three << ...
fmarquet's user avatar
-4 votes
1 answer
104 views

Can I run Arduino code on a 6502?

I've been doing projects with the arduino boards for a long time and accordingly also with the libs from adafruit etc. But that was too boring for me and I wanted to get more into the matter, so I ...
highling's user avatar
0 votes
2 answers
1k views

How does erasing the EEPROM work?

The datasheet for the ATmega328P contains this table, which describes bits 4 and 5 of EECR: EEPM1 EEPM0 Programming Time Operation 0 0 3.4ms Erase and write in one operation (atomic operation) 0 1 ...
glibg10b's user avatar
  • 317
-1 votes
3 answers
726 views

Arduino IDE EEPROM put() then read() returns different data on ESP32

I'm trying to understand how to read/write a UID struct from miguelbalboa to EEPROM to persist a card ID across system restarts on my ESP32-S3 through the Arduino IDE. I expected Put/Get/Read to be ...
Spina's user avatar
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2 votes
1 answer
427 views

What is wrong with the way I write and or read the EEPROM adresses?

Consider: #include <EEPROM.h> byte guifactor1 = 1; byte guifactor2 = 2; byte guifactor3 = 3; byte guifactor4 = 4; byte guifactorgas = 5; byte guifactorwater = 6; volatile unsigned long ...
jay's user avatar
  • 35
5 votes
2 answers
212 views

Can I improve EEPROM lifetime by not changing bits?

In my current project I need to store the current elapsed time in hours to retrieve it in case of power loss. Since I am using a Arduino Nano I would ideally like to use the built in EEPROM without ...
maxmilgram's user avatar
0 votes
1 answer
224 views

Why is EEPROM commit not registering int values?

if(jsonDoc["delayOn"].as<int>() <= 255 && jsonDoc["delayOff"].as<int>() <= 255 && jsonDoc["delayUnitOn"].as<int>() <= 2 &&...
Tinker Ben's user avatar
2 votes
3 answers
513 views

why is my char array empty

following sketch will run totally fine and as expected : #include <Wire.h> #include "SparkFun_External_EEPROM.h" ExternalEEPROM ExtEEPROM; char username[33] = ""; char ...
Musa's user avatar
  • 167
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1 answer
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Erratic behaviour using a DUE with the Microchip 24FC64 EEPROM chip?

I am attempting to read and write from/to an EEPROM chip, and have got access to this 64 kbit device. It appears I can write to the device and read from it, but there appears to be some strangeness ...
J Collins's user avatar
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1 vote
1 answer
1k views

How to set the eeprom initial value when flashing an ESP32

As I use the EEPROM to persist data such as for provisioning the WiFi (SSID and password), I'd like to make sure that the very first time the ESP32 runs, it finds the initial '\0' for the SSID so that ...
Stéphane de Luca's user avatar
2 votes
2 answers
1k views

Read & Write to EEPROM

I need to implement EEPROM Read & Write functionality to my project. I've been learning how to use the EEPROM on the last few days, however I'm struggling to Read & Write Strings to EEPROM. ...
user avatar
1 vote
1 answer
214 views

How to change variable/sketch through a GUI

Over the past few months, I've been working on a wearable computer mouse using an Arduino and a 9-dof sensor. Most of the sketch is complete, and works as expected. Recently, I started investigating ...
Zhelyazko Grudov's user avatar
2 votes
2 answers
570 views

UNO's Internal EEPROM "read" returns incorrect values when it precedes "write"

I am an Arduino instructor and I was preparing some material on the utilization of the Arduino UNO's internal EEPROM when I encountered a problem. The problem is, I am trying to show the original ...
Abdalrahman Seliem's user avatar
1 vote
0 answers
626 views

Arduino Mega as a EEPROM Programmer for Winbond W29EE011 memories

I'm trying to use my Arduino Mega as an EEPROM memory writer. For this project, besides my Arduino Mega, I use an SD Card module, an LCD display and two push buttons to handle the events. Inside the ...
Dan Fayal's user avatar
1 vote
1 answer
1k views

nRF52 non-volatile storage/recall of a variable - is there a simple solution?

I have an Arduino program written for the nRF52 with which runs for a pre-set time-value (i.e. 2 minutes) before shuts off automatically. The variable time-value can be changed via BLE-write by the ...
TommyS's user avatar
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1 vote
0 answers
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Why does this piece of code overflow at 255?

Im having a problem where i got unsinged long variable and i need to increment it in eeprom everytime setup starts and it overflows at 255 back to 0. unsigned long NumberOfBoots = 0UL; #define ...
Nicky's user avatar
  • 11
1 vote
0 answers
121 views

Reading a flash ROM chip (M45PE20) through SPI with an ATMEGA 2560 -- output only FF's

I'm trying to communicate through SPI to a Flash ROM chip (M45PE20) with an ATMEGA 2560. I'm looking to read the data off the chip, but the output I'm getting is nothing but FF's. I've checked my ...
CaesiumWhale's user avatar
2 votes
1 answer
370 views

Serial.println won't format DEC

This is weirding me out. So I wrote to the EEPROM and I would like to read from the address and format it in Base 10, err... Decimal. The normal number thingy that's not ASCII. But it keeps returning ...
Joshua Olalekan's user avatar
0 votes
1 answer
767 views

does EEPROM reset itself when a new code is uploaded?

I have a Nodemcu with which i'm doing a project. So whenever there is a power loss i want values of some of the variables to not be reset, because of that im trying to store the values in EEPROM of ...
rohithrathod banoth's user avatar
1 vote
1 answer
322 views

Neo 6m outputting something i as a noob can't understand

So i connected my ublox neo 6m gps breakout board GY-GPS6MV2 to the arduino software serial and got this result, i used resistors and only supplied 3.3v to the board, gps encode library couldn't give ...
Aayush Garg's user avatar
1 vote
0 answers
227 views

How can I store a value of 1000 over to EEPROM of Arduino Nano?

I need some of your feedback and guidance. In my prototype project powered by Arduino Nano(Space Constraint), it will operate continuously until it reach a maximum of 100 hours. Once it reached 100 ...
Peterhan123's user avatar
2 votes
3 answers
887 views

How can I read the data stored in EEPROM although is powered OFF based on the simple code I wrote?

I need help regarding on EEPROM library. Based on the code below, for every 2 sec, I want to store the int for increase where it will keep increasing by 1. Then, I upload to my Arduino Nano and open ...
Peterhan123's user avatar
1 vote
1 answer
104 views

Compiling Assembly Script in External EEPROM to Arduino Code

I'm working on a simple game console, and I'm planning to use a cartridge system using an EEPROM. I know that you can read and write data from an EEPROM, but can you compile the data into executable ...
jort57's user avatar
  • 13
0 votes
5 answers
475 views

Reading from EEPROM and writing to addressable LED with limited connections

UPDATE Clock speed code has been tweaked as per the suggestion from @timemage due to inability for Wire library to reduce to below 30304Hz. Unfortunately problems still persist: Nothing printed out to ...
user2105725's user avatar
0 votes
2 answers
964 views

Programming AT24C16 EEPROM with Arduino Nano

I have been trying to program an AT24C16 EEPROM and have set up a circuit as per the attached image. I have been using the following Arduino code: #include <Wire.h> #define disk1 0x50 /...
user2105725's user avatar
1 vote
1 answer
240 views

EEPROM programmer works with serial monitor but not with pySerial

I'm trying to modify Ben Eater's eeprom programmer to flash a 32K eeprom, since the arduino has 32K of program data total the data wouldn't fit in the program. So I wrote a python program using ...
bobbbob's user avatar
  • 21
2 votes
2 answers
767 views

Where to store critical data in power outage situation on ESP8266

I want to store a counter that is always changing, but I want it to remain and be able to retrieve it on after a power loss. It's only one long number data, but as it is always changing, I don't know ...
harold's user avatar
  • 121
1 vote
1 answer
1k views

Why isn't this EEPROM.get() working?

I am trying to save a string/char to EEPROM with EEPROM.put() and then get the value, but it doesn't work and I get a blank value when I do a EEPROM.get(). I remember this is how it worked on arduino ...
adrianTNT's user avatar
  • 252
1 vote
1 answer
2k views

ESP32: best way to embed certificates

I'm using the Arduino framework on an ESP32 based board. The board has an SD card slot, but I'm not going to use it. Anyway, I need to store somewhere the certificates. To the the firmware I've just ...
Mark's user avatar
  • 393
1 vote
1 answer
839 views

Is it possible to upload and run code from EEPROM during boot time?

I am having problems while writing custom bootloader, so that it uploads code from EEPROM (for now internal, as I have no external memory in my hands) and writes into flash. After ~2 weeks of ...
Miradil Zeynalli's user avatar
1 vote
0 answers
329 views

EEPROM Arduino library for ESP8266 is not working

I am trying to use EEPROM library from Arduino framework for my ESP8266 project (NodeMCU). I am using Atom with Platformio. Initialization of EEPROM is attempted at void setup() in main.cpp: EEPROM....
hypers's user avatar
  • 111
1 vote
1 answer
524 views

How to convert my Arduino setup to a PIC setup?

I have an arduino setup with LCD, RTC, EEPROM, Reed Switch, AC/DC Buck Converter, 4X4 Keypad. What PIC IC will let me connect with all these(40 Pins), and yet accept Arduino Code. I don't want to ...
hindisong.cc's user avatar
0 votes
1 answer
333 views

Store & retrieve parameters after sketch update

I have a Generic code for some IOT devices which vary in some parameters ( lets say it is only its MQTT name and subscriptions). Since I use OTA to update sketch, I'm looking for a way to A) write ...
guyd's user avatar
  • 1,049
1 vote
1 answer
248 views

Junk values in EEPROM. while writing large values

Facing an issue while writing a large value (like 2000-5000) to EEPROM using EEPROM.put(). For example, While writing 2000 values to address 5 of EEPROM. Some junk values are written automatically to ...
Mayoogh Girish's user avatar
0 votes
1 answer
338 views

Error while inputting EEPROM.read() and EEPROM.write()

I am trying to store data in ATmega328 (Arduino Uno) using the following code using tinkercad: #include <EEPROM.h> void setup() { int addr, data=1; Serial.begin(9600); for (addr=0; addr&...
Manu's user avatar
  • 113
1 vote
1 answer
2k views

Need help with EEPROM not storing array values on ESP8266 after restart

I am struggling through a program. I am trying to store my uploaded string into an array then write that array to EEPROM. I run the program, upload the new array and store it in the EEPROM. all values ...
deathrace2020's user avatar
-1 votes
1 answer
318 views

EEPROM not consistent over reboot

I'am using a Wemos D1 mini V3.0.0 (esp 8266 core). I tried to save a structure in EEPROM memory but all data are lost when i reboot the board. I am using these basics functions : int cle_verif = ...
Marco Bresson's user avatar
0 votes
2 answers
173 views

the use of the Arduino's EEPROM

I want to know the purpose of using the EEPROM because I can't get it, I mean I know that it can store values for a long time, but I just can't get the goal here #include<EEPROM.h> void setup() ...
klay's user avatar
  • 43
2 votes
2 answers
267 views

Arduino Uno SD card storage

I am interested in storing accelerometer data to an SD card. Since power consumption is the main consideration of my project, it is important to do as few writes to the SD as possible, because the SD ...
NickG's user avatar
  • 163
2 votes
3 answers
283 views

Arduino Mega keep states after reprogramming

Based on: https://forum.arduino.cc/index.php?topic=440978.0 And some previous experience with Arduinos. What I would like to accomplish here is that I have a 8 channel relay board with the relays in ...
Elena's user avatar
  • 21
0 votes
2 answers
378 views

store multiple of float type on EEPROM

I have 7 float variables. float temperature, differential, calibration,hta,lta,hha,lha; I want to store them all on the EEPROM memory, how do I calculate the addresses given that there type is ...
Itzik.B's user avatar
  • 131
1 vote
0 answers
225 views

ESP8266 EEPROM Reading extra character

I am very very new to ESP Programming. I am trying to store Strings into EEPROM of ESP8266. I am storing the string into eeprom successfully but while reading it from EEPROM extra character 'd' is ...
java bee's user avatar
0 votes
1 answer
1k views

Managing configurations via EEPROM by writing it with the hex file

I've been looking into I2C bootloaders for an ATTINY coprocessor on a board I'm developing, and I ran into a bit of a snag. I have the need to detect what board the main processor's code is running on,...
user avatar