Writing to UICR_Customer from operating SD system is failing.

[snoonan]

Using SD 6.2 and sDK 15 I need to write to the UICR_Customer space while the BLE system is operating.

I tried pulling example code from https://devzone.nordicsemi.com/f/nordic-q-a/11781/writing-to-uicr-from-application-code and https://devzone.nordicsemi.com/f/nordic-q-a/13742/is-there-sample-code-for-writing-to-an-uicr-register but neither gets the value written to UICR, even after a reboot. 

When running the write routine, I just get a reboot, Trying to isolate it, I get a reboot when I just call nrf_sdh_disable_request() followed by nrf_sdh_enable_request() with no intervening code.

My full routine as of now is:

bool FLSH_WriteData(uint32_t start_addr, const uint8_t *src, size_t len)
{
    uint32_t *src32 = (uint32_t *)src;
    uint8_t addr = (start_addr - (uint32_t )(&NRF_UICR->CUSTOMER[0])) / sizeof(uint32_t);

    addr = 0;
    nrf_sdh_disable_request();
    /* MWU Disable -- This is workaround suggested by Aryan on the Nordic Developer Zone */

    /* Turn on flash write enable and wait until the NVMC is ready: */
    NRF_NVMC->CONFIG = (NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos);
    while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}

//    while(len > 0)
    {
        /* write to the register */
        NRF_UICR->CUSTOMER[addr] = 0x12345678; //*src32;
        while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}

        len -= 4;
        addr += 1;
        src32 += 1;
    }

    /* Turn off flash write enable and wait until the NVMC is ready: */
    NRF_NVMC->CONFIG = (NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos);
    while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}

    nrf_sdh_enable_request();
    return true;
}   

I know about maybe needing to use the MWU enable as well, but that does not help at the moment and still just causes a reboot without writing to the flash.

I have verified that the UICR space I am writing it erased (all 0xFF).

[Stian Røed Hafskjold]

Hi, may I ask why you want to write to the UICR while the softdevice is active? In general it's better to use the FDS module if you want to store data during runtime. UICR is nice to use if you want to store permanent data to the device in production.

[snoonan]

This is for serial number, model settings, and calibration data, programmed in the manufacturing setting but with BLE functions working for board testing.  I don't need to have it working for all cases in production code, just a limited portion of cases which can have some special casing.

[Vidar Berg]

Hi,

It's not necessary to disable MWU, nrf_sdh_disable_request() should do that for you. I think the reboot must be caused by something else in your application. You can place a breakpoint in the app_error_handler to see if there any asserts. In any case, I would suggest that you keep Manufacturing data in a RAM buffer while it's connected, then once disconnected, copy the RAM to UICR.

Something like this:  

1. wait for the disconnect event

2. Stop timer any instances you may have running.

3. Call  FLSH_WriteData()

4. Call NVIC_SystemReset() to reboot your app.