write flash in ble_central\ble_app_uart_c

[Carey]

chip: 52832   .   sdk 12.3\examples\ble_central\ble_app_uart_c\pca10040\s132,    

i use this example to scan ble advistisment,  i want to write some date to flash,  i use flash_word_write , the mcu would restart,  i use sd_flash_write,  the mcu not restart, but seems the data havn't wroten in flash.

i just want to save some data to flash after scaned the BLE,  Can i disable the softdevie before write flash and enable softdevice after write flash?  if can how to disable?  or other methord to write data to flash after scaned ble advtisement?

[Amanda Hsieh]

Hi, 

flash_word_write() typically tries to access the NVMC registers directly, but you shouldn't do that if you are running a SoftDevice. When the SoftDevice is enabled, the SoftDevice API for accessing flash should be used (sd_flash_page_erase/sd_flash_write).

Note: for writing and handling data storage in flash, the libraries nRF5 SDK v12.3.0: Flash Data Storage and  nRF5 SDK v12.3.0: Experimental: Flash Storage are there to make it easier.

 

-Amanda H. 

[Carey]

err_code = sd_flash_page_erase((uint32_t)(120));
APP_ERROR_CHECK(err_code);
nrf_delay_ms(50);

this is my code , the err_code return 0, but when it run to the nrf_delay_ms, the MCU restart. why? 

[Amanda Hsieh]

Hi Carey,

When sd_flash_page_erase() returns NRF_SUCCESS, that only means that the erase request was successfully submitted to the SoftDevice. It does _not_ mean that the erase operation has actually been completed yet. When the erase operation completes, the SoftDevice will generate an event interrupt, and you must call sd_evt_get() to consume it. Please see this post.

Therefore, rather than using a fixed delay, I would recommend you to wait for the event NRF_EVT_FLASH_OPERATION_SUCCESS, telling that the operation was successfully completed.

In addition, it is also good practice to check the returned error code when calling a function.

Please see the documentation of the sd_flash_page_erase() function. You will get one of the following events following the function call:

• NRF_EVT_FLASH_OPERATION_SUCCESS - The command was successfully completed.
• NRF_EVT_FLASH_OPERATION_ERROR - The command could not be started.

 

-Amanda H.