status of SRAM during an over the air update

RE: status of SRAM during an over the air update

weightwatcherphil — Tue, 22 May 2018 22:51:26 GMT

thank you

RE: status of SRAM during an over the air update

Vidar Berg — Tue, 22 May 2018 07:58:08 GMT

You can use the __attribute__ keyword in your code to place a variable in the non_init section:

static uint8_t data[SIZE] __attribute__((section(".non_init")));

Then you need to edit the flash_placement.xml (located in same directory as project file) to ensure the .no_init section is placed in an area of RAM that is not already used by the bootloader or application:

RE: status of SRAM during an over the air update

weightwatcherphil — Fri, 18 May 2018 23:44:35 GMT

I am using the Segger Embedded Studio on the nRF52840 development board

thanks

RE: status of SRAM during an over the air update

Vidar Berg — Fri, 18 May 2018 09:08:50 GMT

Hi,

The DFU process involves system resets (soft), but this does not reset RAM (reset behavior). It is in other words possible to retain the data through DFU given that the data is kept in a non-initialized section of the RAM. This will require changes in the linker configuration for both application and bootloader. I can provide instructions on how to declare a non-initialized RAM section if needed, just need to know which toolchain you are using.