Persistent storage

Question

Hello, 
 
 I have develop a solution that uses openThread with UDP. I want to keep in memory the UDP address of the last device that communicates with me. Thus in case of reset, my device will join again the network and send a sort of "ping" message to this UDP. 
 Sadly I have hard time storing this simple data. What is the simplest/best option ? 
 I have tried to use the nvmc of the nrfx library to write my data in the UICR register. But I have a problem: when doing an erase of the uicr register, firmware is crashing (in the z_arch... file so it gives me no hint). 
 Can you help on this ? 
 Thanks !

Jørgen Holmefjord · Accepted Answer

It is likely that the assert you are seeing from MPSL when directly calling nrfx_nvmc_uicr_erase is because the flash operation will halt the CPU, causing MPSL to be blocked from meeting its deadlines, leading to the assert. 
 The Zephyr flash driver interacts with MPSL through a sync API to schedule operations between radio operations, to prevent asserts. It seems that the Zephyr flash API also enables UICR operations through the Kconfig CONFIG_SOC_FLASH_NRF_UICR, however, I would highly recommend you to store your data in normal flash rather than UICR. The OpenThread stack already utilizes the settings subsystem to store network data, so using this for your own application data storage will not have a big impact on flash usage.

Persistent storage

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