ESP32 Forum

Posted: **Wed Mar 20, 2024 10:53 am**

New to this, trying to store a persistent number between boots but it rolls over after 8 bits. Works as expected until I hit 256. Is each address only capable of holding a byte? How do I abstract that away to store larger numbers?

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#include <EEPROM.h>
#define EEPROM_SIZE 512

int numClick = 0;

in setup()

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EEPROM.begin(EEPROM_SIZE);
numClick = EEPROM.read(0);

in loop() on certain condition

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numClick = EEPROM.read(0);
........
numClick++;
........
EEPROM.write(0, numClick);
EEPROM.commit();

Posted: **Thu Mar 21, 2024 3:22 am**

Yeah, the EEPROM library emulates an actual EEPROM device which stores an array of bytes. If you want to store larger numbers, you'd need to split it into multiple bytes. A better option is to use the Preferences library, which is more flexible as it doesn't have to emulate a hardware device.

Posted: **Thu Mar 21, 2024 4:33 am**

While 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. You do still have to keep track of how many bytes you are using so you can read/write to the correct addresses. See the extra example

Posted: **Sun Apr 07, 2024 1:39 pm**

Thank you both for the info, all working well now with preferences instead

ESP32 Forum

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