nRF5340 - Setting Feature with Custom Partition

Question

1. nRF Connect SDK: v2.3 
 2. Problem Description / Question 
 I'm currently working on implementing a settings feature using either NVS or a file system (NVS preferred), alongside existing Bluetooth (BT) and l ittleFS functionality in my project. 
 Here's a bit more context on my situation:

NVS for Settings vs. Bluetooth: I've been testing the default sample program, settings , and it works perfectly with either NVS or FS. However, when I try to merge this sample program into my existing project, which already utilizes Bluetooth, littleFS, and more, I encounter a fatal kernel error during the bt_enable () . My suspicion is that this issue might be related to a conflict between Setting's NVS settings.

Link Partition Defined in pm_static.yml to Overlay File: I found a POST , and an attached file in the post has a solution for addressing BT and NVS settings by creating a custom_nvs_storage partition in pm_static.yml . However, this project doesn't use settings handlers. In order to utilize settings handlers, my hypothesis is that I need to link the zephyr,settings-partition with the custom_nvs_storage defined in pm_static.yml . However, I haven't been able to find the exact procedure to do this. It seems like it should be a straightforward configuration, but I am struggling to make it work. / {
 
 chosen {
 nordic,pm-ext-flash = &mx25r64;
 zephyr,settings-partition = custom_nvs_storage; // this throws an error saying cannot find custom_nvs_storage.
 };
};

Create an Extra Partition for Settings in external_flash: I want to define an NVS partition in external_flash . Below is what I did, but it doesn't build. 
 // in overlay, to define external_flash:
/ {
 
 chosen {
 nordic,pm-ext-flash = &mx25r64;
 };
};

// -----------------------------
//in pm_static.yml:

custom_nvs_storage:
 address: 0x0
 end_address: 0x3fff
 region: external_flash
 size: 0x4000

If anyone has experience or knowledge related to these issues, I would greatly appreciate your guidance and insights. Any advice or pointers would be immensely helpful. 
 Thank you in advance for your assistance. 
 
 Best regards, 
 Skim.

AHaug · Accepted Answer

Hi, 
 Apologies for the delayed response, I had to check up on some things 
 
 In general we don't recommend you to remove the settings_partition that Bluetooth and/or Matter uses as this is a persistent part of the memory 
 After some input from the creator of the sample you refer to from Setting and using NVS and BT Settings with Static Partition Manager : Adding another settings partition should be relatively straight forward, and can be done by
 
 Adding a new partition in pm_static.yml 
 Change this line: https://github.com/nrfconnect/sdk-zephyr/blob/32a51d982e0b7eba7e458678a8246440b25c3916/samples/subsys/settings/src/main.c#L20

skim said: If I disable it, will the BT_SETTINGS feature be entirely deactivated? Would I then be responsible for handing the storage and restoration of BT state (including pairing keys)? If so, how should I proceed? 
 As the other case you refer to states, this is possible and the sample that Sigurd has provided showcases how to do this. Item number 1 in my previous list explains why you should not disable bt_settings and thus remove the persistant storage for the wireless protocols that use it. 
 skim said: a) Define a partition in the 'external_flash' area using pm_static.yml (Currently, it is defined in the 'primary_flash' area as a name of custom_nvs_storage ) 
 developer.nordicsemi.com/.../partition_manager.html https://github.com/nrfconnect/sdk-zephyr/blob/32a51d982e0b7eba7e458678a8246440b25c3916/samples/subsys/settings/src/main.c#L20 and the Note in that section should explain how to do this 
 Regarding b) and c) I also believe that this should be handled by the sample Sigurd created. I will look closer into the sample at the end of this week, but in the meanwhile I hope this is enough to keep you going 
 Kind regards, Andreas