pstorage, sd_flash, ble_flash, NVMC, ...

[R. Kawajiri]

Hello,

I want to use flash for logging sensor data and sending via BLE. I found several APIs for store data to flash.

• pstorage (Persistent Storage Access Routines)
• sd_flash_...
• ble_flash_...
• NRF_NVMC_...

However, I cannot understand relationships among them and which to use. If you know anything about that please let me know.

Thanks,

[Bill Siever]

pstorage is a higher-level library for managing flash. The sd_flash_ routines are lower-level operations that interact with the NRF_NVMC module's registers (which user code can't interact with directly when using the soft device). The ble_flash_ routines are older than the pstorage library and maybe even a little out of date.

pstorage has some overhead (callbacks / asynchronous operations), but if you need to update flash while "on-air", it's probably the best choice for a few reasons:

1. It avoids conflicts with flash writes and radio on-time
2. It can be used across modules, including when a device needs to "bond" (more secure connections and some persistent configuration settings)