Using FDS to store values

[Ceranthor]

Hi,

I want to run my calibration code only once and this data store in flash (using FDS library) and not again even after restart. Is there any example of this kind of usage? or do i need to run calibration code and flash another code and use data stored in flash after calibration?

[Kenneth]

Hi, I guess there are different ways this can be done. If your application will be using FDS (e.g. due to the application support BLE bonding), then it may make sense to also store any application specific data (e.g. calibration data) using FDS:
https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/fds_example.html

The intention though is that you have 31 words in UICR that you can use to store persistent data that is set in production, and should not change in the lifetime for the product, so this may also be something you can look into:
https://infocenter.nordicsemi.com/topic/ps_nrf52840/uicr.html#register.CUSTOMER-0-31 

Note that data in UICR can not be erased or overwritten.

[Ceranthor]

I have 9 values (uint32_t) from calibration program and i need to store them in flash (than i change the program to normal one). They cannot be erased after and program will only read them. There will also be OTA updates and they also cannot erase this piece of flash.