Electronic – How to store persistent values in STM32F407VGT6 embedded microcontroller

flashmicrocontrollerstm32

I want to store 3 integer values in the flash memory of the microcontroller so that these values are not lost if the device has a power outage.

I am trying to understand which type of memory to use for this purpose and how exactly how can I write to and read from this memory block.

I am doing a hobby project to use a HMI to input data to a PLC which will then drive several motors to control the movement of toy quadcopter.

I am using the Keil uvision IDE.

Some additional notes:

  • The values will be changed once every 2-3 months.
  • There can be power outage during the value update process.
  • Its not critical if process is interrupted and we lose the latest value entered.

Best Answer

You can use so called EEPROM emulation, which uses a part of the Flash memory to be used as EEPROM.

You can read all about it for the STM40x/STM41x in the following document:

https://www.st.com/resource/en/application_note/dm00036065-eeprom-emulation-in-stm32f40x-stm32f41x-microcontrollers-stmicroelectronics.pdf

Of course this EEPROM memory will reduce from the regular Flash memory. It will be needed to assign a full page (not sure how many bytes), but one page is more than enough for your 3 bytes.

Note to think about wear levelling in case you need to store those 3 values often (use different pages if so).

For others: There are different application notes for other STM32 models.

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