Saving sensitive data before soft reset with OTA update for ESP32/ESP8266

Hi,

I need to save in flash or eeprom some sensitive data necessary for the operation of the device after resuming operation after a reset. Unfortunately, the frequency of changing the values of the variables during operation does not allow me to use flash or eeprom on the fly because they would run out very quickly due to the limit of writes.
Is it possible to monitor some kind of flag that would allow to dump data before soft reset ? this only applies to the situation when restarting after a firmware update via OTA, it does not apply to power off as the chip is powered from batteries.

Best regards

Use FRAM, or just SRAM if you have the chip powered all the time.

Added after 2 [minutes]: .

Example of FRAM: 512B (512x8) I2C memory
https://www.mouser.pl/ProductDetail/Fujitsu-S...-G-JNERE1?qs=HBWAp0VN4RjODl%252BGKL9JWw%3D%3D

Added after 1 [minute]:

And here you have the CFI:
https://www.mouser.pl/ProductDetail/Infineon-...es/FM25L04B-G?qs=pA5MXup5wxElRCah1DKWAQ%3D%3D

Thanks for the idea. I don't want to extend the controller with more circuits. I want to use the capabilities of esp32 (if it has them) to detect the state before soft reset and save the data, the data is not much because it is just 3 variables of 4 bytes.

Greetings

Slawek K. wrote:

Is it possible to monitor some flag that would allow to dump data before soft reset ?

.
There is a function in the ESP32 esp_register_shutdown_handler () with which you can "plug in" your own function that will execute before the soft reset of the chip.
Link .

@khoam , thanks .

Greetings