how does nrf52833 jump to bootloader?

[wzszzxj]

Hi,All:

  As the topic,which address is the mbr jumping to bootloader by ?0x10000ff8 or 0x10001014?  and how to feed  the mbr para register  0x10000ffc  and the 0x10001018?

[Carl Richard]

Hello!

You can find more information about this in the Bootloader memory layout documentation. Here it says that the Bootloader start address on the nRF52833 is 0x0007 8000.

Best regards,
Carl Richard

[wzszzxj]

Thank you for you reply!  At the first,I must say,I didn't make the bootloader follow the official program routine。I just make a hid class communication in bootloader.but now  when I combine app.hex softdevice.hex  app.hex  together, It can't turn into bootloader,I want to know how to set  the  mbr  para  by manual?that is include to set  the mbr  address   bootloader addr,and the parameter . 

[Carl Richard]

Did you figure out the problem? If not I can do some investigation to find out.

Best regards,
Carl Richard

[wzszzxj]

Hi,Carl:

 The problem is still, Now two ways, but there is problems in two ways.

1.I just make a bootloader by usb hid, When I burn it in the chip,it can go perfit. But when I don't know how to burn the my application include softdevice to the chip ,it will cover my bootloader's MBR，my problem is how to move bootloader MBR to another area? and how to jump to the bootloader when necessary?

2.I make a bootloader with softdevice,But  when I downdload application to the chip, the softdevice will change my downloading's data, and destroy my bootloader.In this way ,how to stop the softdevice?

[Carl Richard]

Hello again! 

I need some clarification here. The MBR is a part of the Softdevice, so you should not be worried about that being overwritten. You can read more about how the MBR and bootloader works in the Softdevice documentation. In short the MBR first checks for a bootloader start address at 0xFF8, then if empty, it checks for a bootloader start address in UICR.NRFFW[0].

Are you making your own bootloader? Have you looked at the DFU Bootloader samples in the SDK? Among them is a sample for a Serial USB bootloader. I also suggest reading the Getting started with Nordic's Secure DFUI bootloader guide here on DevZone.

Best regards,
Carl Richard