Change the allocation for the EEPROM and the program memory

[taltalp]

Hello,

We are trying to use the EEPROM library for logging temperature, and we use STM32L452RE which has a 512kB flash.
As we read the EEPROM library, its size is limited up to 2kB, however the program memory has 510kB.
Can we change the allocation for that?
And where is the memory map defined?

[fpistm]

Hi, I really not recommend to use EEPROM to log data. It uses the flash memory which has a limited number of R/W cycles.

[fpistm]

If you don't use the EEPROM library all flash is used. Flash is not reserved for it.

Example for Nucleo L452RE:
https://github.com/stm32duino/Arduino_Core_STM32/blob/621d75921205acdeef53220897c6f815c227a3f0/boards.txt#LL563C46-L563C47

and its linker script:

Arduino_Core_STM32/variants/STM32L4xx/L452RETxP/ldscript.ld

Line 40 in 621d759

FLASH (rx) : ORIGIN = 0x8000000 + LD_FLASH_OFFSET, LENGTH = LD_MAX_SIZE - LD_FLASH_OFFSET

LD_FLASH_OFFSET is 0 so the LD_MAX_SIZE is set to max size defined in the boards.txt: 524288 (512K).

[taltalp]

Thank you.
So if we don't overwrite the firmware on the flash, the full addresses are open to write?
Or is there any write protections for the program area?

[fpistm]

You have access to all the flash. Protection is generally managed by option bytes which is out of scope of stm32duino. It is managed by user.

[taltalp]

Ok that's make sense.
Thank you for all your support!

[fpistm]

Welcome 😉