Persistent storage section in NRF52840 Flash

[albert_1977]

Hi all,

On a BLE project I was working using version 2.5.0 of the VS Code dev environment I was able to set up a partition where I could store non volatile data, such as BLE name, serial number, etc.

I have updated to 3.11 and if I understand correctly the IDE uses Sysbuild now. The old configuration does not work anymore but I need to get that storage space back up.

I'm trying to set up a small partition at the last 4KBytes of the flash memory so I can update those parameters when required. That means that my main memory would be 996 KBytes long with a last section of 4 KBytes.

I'm struggling to find an example how to define the partition and how to use the Zephyr API to delete, read or write that section.

Any help or pointers to documentation, examples, etc, is appreciated.

Kind regards,

Alberto 

[albert_1977]

Ok, I got it running so far. This is what I did, based on several examples:

pm_static.yml:

app:
  address: 0x0
  region: flash_primary
  size: 0xFE000
EMPTY_0:
  address: 0xFE000
  region: flash_primary
  size: 0x1000
custom:
  address: 0xFF000
  region: flash_primary
  size: 0x1000
sram_primary:
  address: 0x20000000
  end_address: 0x20040000
  region: sram_primary
  size: 0x40000

Lines added to prj.conf:

CONFIG_FLASH=y
CONFIG_NVS=y
CONFIG_MPU_ALLOW_FLASH_WRITE=y
CONFIG_NRFX_NVMC=y

Now I'm able to use:

nrfx_nvmc_page_erase(PM_CUSTOM_ADDR);
nrfx_nvmc_words_write(PM_CUSTOM_ADDR, (uint8_t*)&custom_var, sizeof(custom_var)/4);

It seems to work well after a few tries.

Kind regards,

Alberto

[Amanda Hsieh]

Happy to know it works.