ot_flash_data in nrf_connect_sdk

[Bhumika]

Hi,

In my application, I am writing in flash.

But when I do so, my openthread data in flash gets overwritten, the node doesn't retain its commissioning data.

In nrf_SDK_For_Thread_and_Zigbee, thread_secure_dfu_client_gcc_nrf52.ld files, it specifies 

FLASH (rx) : ORIGIN = 0x1000, LENGTH = 0xf3000

ot_flash_data (r) : ORIGIN = 0xf4000, LENGTH = 0x4000

So I have used 0x000F2B00 this location and this used to work fine in my previous application.

But in my current application, which is upon nRF_Connect_SDK, I am unable to figure out this address.
Please suggest where I can find the address  of ot_flash_data in nRF_Connect_SDK?

[Edvin]

Hello,

By default, it looks like it will use 0x000F8000 -> 0x000F8FFF (you can check this by using nRF Connect for Desktop -> Programmer).

But I guess it is not always the case. Depending on whether you would use a bootloader, 

Do you intend to have a bootloader to make sure it doesn't collide in the future, or is it enough to know what it is in this particular case? (because then I have to investigate where it is decided what flash address to use). 

Best regards,

Edvin

[Bhumika]

I want to implement DFU in my application in the future, so I understand bootloader will be essential at that point.

So this is not enough in my case, bootloader will come into the picture in the next development phase. 

Please investigate further and suggest accordingly. 

[Edvin]

I understand,

In the case where you have a bootloader, the story is a bit different, actually. Adding the bootloader (CONFIG_BOOTLOADER_MCUBOOT=y), will also create a file called partitions.yml inside your build folder. There you should see a partition called "settings_storage", and the start and end address of that partition:

app:
  address: 0xc200
  end_address: 0x85000
  region: flash_primary
  size: 0x78e00
mcuboot:
  address: 0x0
  end_address: 0xc000
  placement:
    before:
    - mcuboot_primary
  region: flash_primary
  size: 0xc000
mcuboot_pad:
  address: 0xc000
  end_address: 0xc200
  placement:
    align:
      start: 0x1000
    before:
    - mcuboot_primary_app
  region: flash_primary
  size: 0x200
mcuboot_primary:
  address: 0xc000
  end_address: 0x85000
  orig_span: &id001
  - app
  - mcuboot_pad
  region: flash_primary
  sharers: 0x1
  size: 0x79000
  span: *id001
mcuboot_primary_app:
  address: 0xc200
  end_address: 0x85000
  orig_span: &id002
  - app
  region: flash_primary
  size: 0x78e00
  span: *id002
mcuboot_secondary:
  address: 0x85000
  end_address: 0xfe000
  placement:
    after:
    - mcuboot_primary
    align:
      start: 0x1000
  region: flash_primary
  share_size:
  - mcuboot_primary
  size: 0x79000
settings_storage:
  address: 0xfe000
  end_address: 0x100000
  placement:
    align:
      start: 0x1000
    before:
    - end
  region: flash_primary
  size: 0x2000
sram_primary:
  address: 0x20000000
  end_address: 0x20040000
  region: sram_primary
  size: 0x40000

Best regards,
Edvin