Easiest way to store in flash in runtime in an app already using settings with BLE

[Pedro]

Hi!

I have a BLE service which exposes the Device Name characteristic to allow user to change BLE name showed when advertising. I need to store this name in flash in order to load it next time the system is powered on. 

How can I do that? I've been trying with settings subsystem but it is already used by BLE stack, so I get a hard fault (MPU FAULT).

Thanks and kind regards,

Pedro.

[Sigurd]

Hi!

Try using nvs for this. https://github.com/nrfconnect/sdk-zephyr/tree/main/samples/subsys/nvs

Use the BLE api bt_set_name() to set the name at runtime. Remember to set CONFIG_BT_DEVICE_NAME_DYNAMIC=y

[Pedro]

Hi Sigurd,

Won't it cause a conflict with settings subsystem, used by BLE?

I tried a few days ago using NVS and got MPU hard fault. Maybe because there is only one storage partition and it is already used by settings subsystem? Or maybe I did something wrong.

I will try again with NVS.

Thanks!

[Sigurd]

Pedro said:

Won't it cause a conflict with settings subsystem, used by BLE?

NVS is the backend, it supports several "users". Maybe this post here is helpful,  Hard fault when using NVS with Zephyr on nRF52 (CONFIG_PM_PARTITION_SIZE_NVS_STORAGE and CONFIG_MPU_ALLOW_FLASH_WRITE  usage)

[Pedro]

Hi Sigurd,

I tested with NVS following this example https://github.com/nrfconnect/sdk-zephyr/tree/main/samples/subsys/nvs and I only could make it work when not calling bt_enable(). After calling bt_enable(), it does not generate any hard fault or similar, but does not store data in flash.

I finally used settings to store my custom data. I leave the code here in case it helps someone: ble-io-bridge-periph-mod.zip

Thanks and kind regards,

Pedro.