problem about DFU

[jane xue]

Hello I am using nrf51822 .The function of DFU has worked well,but some weird problems puzzle me. 1、After DFU is successful,what is nrf51822's working state? Does it reset?From bootloader?Or directly enter into the BANK1 application program? the problem of my device is that the ADC value changes (less than the normal value) after DFU.If I reset the nrf51822(or wake from the deepsleep state),the ADC value can be right.would you tell me the reason about that or the nrf51822's working process after DFU. 2、 If there is some error,where does the program pointer will go. I do the debugging with the jlink, and find that after DFU finishes the program runs to this function's( void services_init(void)) last statement and the program pointer's position is unknown. Look forward your reply,thank you . Best wishes!

[Bjørn Kvaale]

Are you using the ble secure dfu bootloader example in SDK 12.3? Have you followed the link on the nordic infocenter or the secure dfu bootloader blog post?

[jane xue]

Hi,Bjørn thank you for your reply. This part of DFU function was finished by other person.I took over his work,so I can't fully understand DFU.but the DFU has strange problem,so I post it . I am learning the dfu and will amend it . thank you very much!

[jane xue]

Hi,Bjørn I will ask for you again. 1、In the bootloader ,after DFU,why it districtly enters into Application program,rather than systerm reset? 2、if bootloader executes the DFU and defines the DFU service,if after DFU it districtly enters into application program and in the application program again defines the DFU service,what will happen? thank you again!

[Bjørn Kvaale]

Hi Jane, sorry for the delayed response. If you take a look at the bootloader_secure example in SDK 12.3 for example (SDK12.3/examples/dfu/bootloader_secure), you notice that in the main() function of the main.c file that the function nrf_bootloader_app_start(MAIN_APPLICATION_START_ADDR) is called. This is verified by taking a look at this link: "If there is a valid application, the DFU bootloader starts the application, unless it is explicitly put into DFU mode (for example, by pressing a button)." Normally it is the DFU bootloader that initiates the DFU process, not the application itself (see blog post). It is possible to jump from the application to the dfu bootloader (see link), so I guess you could initiate the DFU again if you want.

[jane xue]

Hi,Bjørn thank you for your reply.I will see it carefully. Best wishes!