I want to keep the previously set values ​​undeleted even after OTA

[alex kim]

Hi, Everyone

Environment: SDK15.3, nRF52840, Keil Compiler

I want to keep the previously set values ​​undeleted even after OTA

My question is
1) Which method is better to use UICR, FICR or FDS?
2) What should I do if I keep the previously set values ​​using the recommended method?

Best regards,

[Vidar Berg]

Hi, 

I would recommend you to use FDS for this. Just remember to make sure the NRF_DFU_APP_FLAG_AREA_SIZE flag matches the size of your FDS region so the data cannot become overwritten during the DFU process. UICR is primarily intended for data you only store once and never update. Storing of a serial number, for instance. FICR is programmed in our production and cannot be erased.

Best regards,

Vidar

[alex kim]

Hi, Vidar

I searched dfu and app examples but couldn't find them.

Where is NRF_DFU_APP_FLAG_AREA_SIZE defined?

Best regards,

Alex

[Vidar Berg]

Hi Alex,

Sorry, it was a typo, it's called NRF_DFU_APP_DATA_AREA_SIZE and is defined in nrf_dfu_types.h and in the bootloader's sdk_config header.

Memory layout

[alex kim]

Hi, Vidar

Thanks for the quick response.

My FDS Setting is

#define FDS_VIRTUAL_PAGES 3

#FDS_VIRTUAL_PAGE_SIZE is 1024.

Can I set NRF_DFU_APP_DATA_AREA_SIZE to 3 * 1024?

Best regards,

Alex

[Vidar Berg]

Hi Alex, 

FDS_VIRTUAL_PAGE_SIZE is given in number 4-byte words, so each FDS page is actually 4096 bytes. So should be 3 * 4096

Best regards,

Vidar