SDK 13.0: fds_init() causes errors unless doing a full FLASH erase

[ivan]

We are evaluating the nRF5 SDK 13.0 to upgrade our projects from v12.0 and it looks like it has a bug related to the FDS functionality.

I managed to reproduce it on the clean ble_app_hids_mouse example. Simply building and programming it together with the softdevice on a device that previously ran code from SDK v12 results in the following behavior:

1. peer_manager_init() eventually calls fds_init() with the following call stack:

   pages_init()
   fds_init()
   pds_init()
   pm_init()
   peer_manager_init()
   main()
   

2. pages_init() searches the FLASH pages for pages with its signature, does not find enough and returns with the NO_SWAP error.

3. As a result, pm_init() fails and the firmware hangs in app_error_handler().

Doing a full FLASH erase before programming the firmware seems to help. Is there a better workaround to this?

[Jørgen Holmefjord]

FDS requires fully erased pages to setup. Ìt will not erase any pages by its own. Do you change any settings from SDK 12 to SDK 13? What are the exact error codes returned by the functions?

[ivan]

pages_init() returns NO_SWAP. Then fds_init() quits with FDS_ERR_NO_PAGES. I did not change any settings, just downloaded a clean SDK v13, built the project with gcc/make and programmed it. The same device was previously used to try out several different projects, so the FLASH memory contents could contain random bits of other firmware.

[Jørgen Holmefjord]

This is expected behaviour. You need to provide erased pages for the system to be able to setup. FDS requires fully erased pages, and it will not erase any unknown pages by itself.

[Electronics111]

So how do I erase the pages if I've stored data that I then want to retieve on a device reboot? And even if I didn't, how would I erase the flash before initialising the peer_manager which is required to then start the pstorage flash driver?

[Jørgen Holmefjord]

You can erase the flash pages before flashing the application, or you can use the NVMC driver. When FDS initializes the pages it will use, the pages will be tagged with a "magic word" that FDS recognises. Peer manger should use FDS, not pstorage. I would recommend that you stick to using FDS/fstorage and remove pstorage from your application.