can Bootloader call API in SoftDevice?

[Davis Zheng]

my nRF52840 has MBR, SoftDevice, Application and Bootloader.

Can Bootloader call API in SD? 

Will it be an issue? If I need to upgrade SD (could be a newer version), Application and Bootloader.

Any suggestion on implementing Bootloader? 

[Einar Thorsrud]

Hi,

Yes, a bootloader can call SoftDevice APIs. That is what our BLE Secure DFU Bootloader does.

[Davis Zheng]

Thanks for your answers and information!!

SVC 0x18 interrupt handler is implemented in MBR. right ?

48 uint32_t nrf_dfu_mbr_copy_bl(uint32_t * p_src, uint32_t len)
49 {
\ nrf_dfu_mbr_copy_bl: (+1)
\ 0x0 0xB538 PUSH {R3-R5,LR}
\ 0x2 0xB084 SUB SP,SP,#+16
\ 0x4 0x0004 MOVS R4,R0
\ 0x6 0x000D MOVS R5,R1
50 uint32_t ret_val;
51 uint32_t const len_words = len / sizeof(uint32_t);
\ 0x8 0x08AD LSRS R5,R5,#+2
52
53 sd_mbr_command_t command =
54 {
55 .command = SD_MBR_COMMAND_COPY_BL,
56 .params.copy_bl.bl_src = p_src,
57 .params.copy_bl.bl_len = len_words
58 };
\ 0xA 0x4668 MOV R0,SP
\ 0xC 0x2110 MOVS R1,#+16
\ 0xE 0x.... 0x.... BL __aeabi_memclr4
\ 0x12 0x9401 STR R4,[SP, #+4]
\ 0x14 0x9502 STR R5,[SP, #+8]
59
60 ret_val = sd_mbr_command(&command);
\ 0x16 0x4668 MOV R0,SP
\ 0x18 0xDF18 SVC 0x18
61
62 return ret_val;
\ 0x1A 0xB005 ADD SP,SP,#+20
\ 0x1C 0xBD30 POP {R4,R5,PC}
63 }

[Einar Thorsrud]

Yes, that is implemented in the MBR

I was not specific in my previous reply, but I woudl advice that you use the example BLE bootloader as a basis for your bootloader. In most applications it can be used with little or no change (other than adapting the configuration in sdk_config.h and using your own public key).

[Davis Zheng]

Thank you very much!!