Is it possible to use secure dfu (SD130v2, SDKv12.2) with 16k RAM dervices (concrete nRF51822 256k flash, 16k ram)?

[kvrbek]

Hi everybody

Is it possible to use secure dfu (SD130v2, SDKv12.2) with 16k RAM dervices (concrete nRF51822 256k flash, 16k ram)? When I try to shrink ram in dfu project provided in sdk, linker complaining about insufficient RAM.

Regards, Krunoslav

[Colin Zhu]

Hi,

I'm afraid nRF51822 is a little tight on RAM usage. Since the softdevice alone will consume some RAM. The left is not enough for doing a secure DFU. You need to do a lot of modifications in the SDK and actually I'm not sure whether it's a good idea.

I suggest you either turn to nRF52832 or other RAM friendly DFU

[bjorn-spockeli]

Hi kvrbek,

I was able to compile the Secure Bootloader with the following ROM/RAM settings

IROM1 Start: 0x3AC00    Size: 0x5000
IRAM1 Start: 0x200025E0 Size: 0x19A0

The IRAM1 start address can be lowered from 0x20002C00 to 0x200025E0 since the S130 v2.0 only needs 0x25E0 bytes of RAM and not 0x2C00 bytes as set by default. You can verify this yourself by looking at the The sd_ble_enable function. It takes app_ram_base as an argument and and on return this will contain the minimum start address of the application RAM region required by the SoftDevice for this configuration. Calling sd_ble_enable() with *p_app_ram_base set to 0 can be used during development to find out how much memory a specific configuration will need.

[kvrbek]

Yep, it is building now. Thank you!

[bjorn-spockeli]

Happy to help :) I would appreciate if you could mark the answer as correct by clicking the checkmark in the circle to the left of the answer.