Write to UICR CUSTOMER register not working

Question

Hi,

Update:

Module: nRF52832

SDK v 14.2, SD v5.0, windows platform

I am trying to write to save a value to UICR customer register. My routine for saving the value to the register goes like this:

            err_code = sd_softdevice_disable();
            if(err_code == 0)
            {
              NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Een<<NVMC_CONFIG_WEN_Pos;
              while(NRF_NVMC->READY == NVMC_READY_READY_Busy){};

              NRF_UICR->CUSTOMER[4] = 0x0A0A0A0A;

              NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Ren<<NVMC_CONFIG_WEN_Pos;
              while(NRF_NVMC->READY == NVMC_READY_READY_Busy){};
              printf("HW calibration exited.\r\n");
              nrf_delay_ms(5);
              NVIC_SystemReset();
            }

While debugging, i can see the CONFIG register is changed to Wen and after writing, changed back to Ren. But after rebooting, i dont see the value being written to the register.

Would any of you what i am doing wrong here? Followed the process as mentioned in some of the forums here and the reference manual for NRF52832.

Thank you.

run_ar · Accepted Answer

No, you do not need to erase the uicr before writing to it. If you know you will only call that functions once, I guess you do not have to check. But if you might end up calling it again, it would be a good idea to check the content to make sure it's empty before writing. 
 Guess you saw the description: 
 /**
 * @brief Write consecutive bytes to flash.
 *
 * @param address Address to write to.
 * @param src Pointer to data to copy from.
 * @param num_bytes Number of bytes in src to write.
 */
void nrf_nvmc_write_bytes(uint32_t address, const uint8_t * src, uint32_t num_bytes); 
 So do something like this, p_src being what you want to write to uicr: 
 UICR_START_ADDR ((uint32_t)&NRF_UICR->CUSTOMER[0])

uint32_t num_bytes = p_src_length; //also check against your maximum allowed length
nrf_nvmc_write_bytes(UICR_START_ADDR, (const uint8_t *) p_src, num_bytes);

Write to UICR CUSTOMER register not working

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