RE: Jump from bootloader to application, SDK 15.3, no SoftDevice

Cecylia — Wed, 26 Jun 2019 01:15:29 GMT

Hi Einar,

I really appreciate your prompt and very helpful feedback!
I found more info online based on the keyword "VTOR", since I wasn't sure how to change the VTOR.

I just realized that these 2 lines in nrf_bootloader_app_start actually disable all the interrupts:
NVIC->ICER[0]=0xFFFFFFFF;
NVIC->ICPR[0]=0xFFFFFFFF;

I simply added this line right after:
SCB->VTOR = (uint32_t) start_addr;

And continued with nrf_bootloader_app_start_final which eventually calls app_start that takes care of setting the new_msp and new reset_handler.

It works :) No more hard fault.

Thanks!!
Cecylia

RE: Jump from bootloader to application, SDK 15.3, no SoftDevice

Einar Thorsrud — Tue, 25 Jun 2019 12:03:04 GMT

Hi,

[quote user=""]1) Is this design feasible, or do I need to use MBR?[/quote]

Yes, it is feasible. The reason for having an MBR is that it allows the update of the bootloader itself. Since you don't use the SoftDevice and as long as you don't need a way to (safely) update the bootloader, then there is no need for an MBR.

[quote user=""]2) Do i need to do anything to forward interrupt to application?[/quote]

Yes. Since you don't use MBR or SoftDevice, the most straightforward would be to simply use the VTOR.

[quote user=""]3) I don't see interrupts_disable in SDK 15.3. Do I need to copy this from the old code?[/quote]

The interrupt forwarding in the bootloader example in the SDK depends on the MBR. You can see how it is done there in the implementation of nrf_dfu_mbr_irq_forward_address_set() in <SDK15.3>\components\libraries\bootloader\dfu\nrf_dfu_mbr.c, but this is not relevant if you don't use the MBR.

[quote user=""]4) The new jump_to_addr is slightly different from the older StartApplication. But they should mean the same right?[/quote]

Yes.