NVMC write is not possible after softDevice initialization

[masterLee]

Hi,

I want to write to the NVMC UICR Customer[n] memory addresses during code execution.

 //----------------ERASING/WRITING TO NVMC UICR---------------------
   NRF_LOG_INFO( "%x", NRF_UICR->CUSTOMER[0]);                                                // Read current data

   NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Een << NVMC_CONFIG_WEN_Pos;                             // Erase Enable
   while (NRF_NVMC->READY == NVMC_READY_READY_Busy);

   NRF_NVMC->ERASEUICR = NVMC_ERASEUICR_ERASEUICR_Erase << NVMC_ERASEUICR_ERASEUICR_Pos;      // Erase UICR
   while (NRF_NVMC->READY == NVMC_READY_READY_Busy);

   NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos;                             // Write Enable
   while (NRF_NVMC->READY == NVMC_READY_READY_Busy);

   NRF_UICR->CUSTOMER[0] = 0xDEADBEEF;                                                        // Write new Value 
   while (NRF_NVMC->READY == NVMC_READY_READY_Busy);

   NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos;
   while (NRF_NVMC->READY == NVMC_READY_READY_Busy);
   NRF_LOG_INFO( "%x", NRF_UICR->CUSTOMER[0]);

   //--------------------------------------------------------------

I noticed that I can write/read/erase those addresses only before the initialization of the softDevice

When I try to execute the same code after softDevice initialization I can only read but not write or erase those addresses

What am I missing here?

Thank you for your time

[Jørgen Holmefjord]

Hi,

The softdevice will restrict access to the NVMC peripheral when it is enabled. See this post.

Note that the UICR CUSTOMER registers are mainly intended for parameters that are updated once or very seldom, as it is required to erase the full UICR to overwrite one register. For storing data that will be updated more often, you can write to flash through the Softdevice Flash API.

Best regards,
Jørgen