nrfx_nvmc_page_erase causes NRF_FAULT_ID_SD_ASSERT

[Rick N]

My issue seems to be similar to DRGN-12539.  However, I am erasing internal flash.

I am calling in a loop nrfx_nvmc_page_erase to erase multiple pages of flash.  At first, I erase all the required pages at once

ret_code_t erase(uint32_t startAddress, uint32_t pageCount)
{
  for (uint32_t i = 0; i < pageCount; i++)
  {
    VERIFY_SUCCESS(nrfx_nvmc_page_erase(startAddress + (i * NVM_PAGE_SIZE)));
  }
  return NRF_SUCCESS;
}

I change it to use an app timer that will only erase one page at a time.

#define START_ADDRESS (0x00060000)
#define PAGE_COUNT 5
#define NVM_PAGE_SIZE (4096) // Bytes in one page

APP_TIMER_DEF(m_erase_timer);

static uint32_t m_erase_page_offest = 0;

static void erase_page(void *p_context)
{
  UNUSED_VARIABLE(p_context);
  
  if (m_erase_page_offest < PAGE_COUNT)
  {
    uint32_t address = START_ADDRESS + (m_erase_page_offest * NVM_PAGE_SIZE);

    ret_code_t err_code = erase(address, 1);
    APP_ERROR_CHECK(err_code);
    
    m_erase_page_offest++;
  }

}

/**@brief Function for the Timer initialization.
 *
 * @details Initializes the timer module.
 */
static void timers_init(void)
{
  // Initialize timer module, making it use the scheduler
  ret_code_t err_code = app_timer_init();
  APP_ERROR_CHECK(err_code);

  app_timer_create(&m_erase_timer, APP_TIMER_MODE_REPEATED, erase_page);
}


/**@brief Function for application main entry.
 */
int main(void)
{
  ret_code_t err_code;

  timers_init();

  err_code = app_timer_start(m_erase_timer, APP_TIMER_TICKS(1000), NULL);
  APP_ERROR_CHECK(err_code);

  for (;;)
  {
    if (NRF_LOG_PROCESS() == false)
    {
      nrf_pwr_mgmt_run();
    }
  }
}

/**
 * @}
 */

In both case, I will get a NRF_FAULT_ID_SD_ASSERT during the process.  It varies on which page it ultimately triggers the failure.

I'm using S112 v7.2.0 on NRF52832

[Jørgen Holmefjord]

Hi,

If you have enabled the softdevice, you need to use the softdevice Flash memory API to erase/write flash. Flash operations will halt the CPU, preventing the softdevice from handling time-critical tasks. This will lead to the softdevice asserting.

When calling sd_flash_page_erase(), the softdevice will schedule the erase between critical events in the future. Once the erase is completed, an event will be generated and passed to the softdevice event handler declared in the application.

Best regards,
Jørgen

[Rick N]

Is there an example that I can use as reference?   The API mentions NRF_EVT_FLASH_OPERATION_ERROR that may happen, but I'm not sure what event handler I need to register for to monitor.

[Jørgen Holmefjord]

The examples in the SDK uses the SoftDevice Handler library to pull events from the softdevice, and pass the events to subscribing modules across the SDK.

You can see an example of how a module declares a SOC handler and receives flash-events from the SDH library in the Fstorage softdevice backend (components\libraries\fstorage\nrf_fstorage_sd.c)

[Rick N]

Thanks for the quick response.  I ultimately just used the fstorage module.