Example For Using UART DFU on NRF52832 on both sides of communications

[Pamela Keiles]

Hello,

I am trying to figure out which example is the closest fit for our design. We are using a 2 processor solution in our product, and the firmware for the NRF52832 has to be able to be upgraded via the UART connection to the main processor. I have found some examples here, but usually it's using a PC application or over the air which does not apply to our design. Also, I'm confused abut some of the examples on the side of the NRF52832 in terms of performing the update. There are references to a "full modem" update, but what is meant by modem? This will be a simple direct UART communication update, is this done via the application on the Nordic chip or can it be done via the bootloader directly?

This has to be a common approach, I'm just unsure where to start. Note I am using the latest SDK release 1.9.1.

Thanks for your help.

Regards,

Pam

[Pamela Keiles]

Hi Simon,

I will be performing the second slot flash update from the app, which receives it via the UART directly. So it sounds like all I have to do after programming the flash with the new image, is call the "boot_write_img_confirmed() routine and force a reboot, is that correct?

Thanks,

Pam

[Simon]

You do it in the opposite way. After you've programmed the secondary flash with the new image, you force a reboot, then you call boot_write_img_confirmed() routine from the new image (now present in the primary slot).

Like I explained in this answer: https://devzone.nordicsemi.com/support-private/support/288653#permalink=757710 

[Pamela Keiles]

Hi Simon,

Great, I think I got the sequence from your explanations. I'll be working on this part of the design the next couple of days and I'll let you know if I have any other questions. I will also be trying to "break" the bootloader to make sure it recovers nicely, such as only a partial image being present in the second bank.

Thanks for all your detailed help.

Best regards,

Pam

[Pamela Keiles]

Hi Simon,

I'm struggling with accessing the flash partition area directly using the partition manager defines and the device tree specification for my board. I was referencing the "soc_flash_nrf" example, but it doesn't seem to incorporate the partition manager, which I believe is automatic when using "mcuboot" correct?

I have also been looking at the resultant defines in the "pm_config.h" file, and they are not what I would expect from my board.dts file.

Specifically the sizes and start addresses seem wrong. Here is how the flash is defined in my device tree file:

&flash0 {

    partitions {

        compatible = "fixed-partitions";

        #address-cells = <1>;

        #size-cells = <1>;

        boot_partition: partition@0 {

            label = "mcuboot";

            reg = <0x00000000 0xc000>;

        };

        slot0_partition: partition@c000 {

            label = "image-0";

            reg = <0x0000C000 0x32000>;

        };

        slot1_partition: partition@3e000 {

            label = "image-1";

            reg = <0x0003E000 0x32000>;

        };

        scratch_partition: partition@70000 {

            label = "image-scratch";

            reg = <0x00070000 0xa000>;

        };

        storage_partition: partition@7a000 {

            label = "storage";

            reg = <0x0007a000 0x00006000>;

        };

    };

};

 

However when I look at the resultant "pm_config.h" file, the values do not match. Maybe this is effected by this unexpected "PM_MCUBOOT_PAD_SIZE" added which messes up the defined starting locations of the slots?

I'll keep plugging away at this, but any help you can provide would be great.

Thanks,

Pam

[Simon]

When your project contains child images (like mcuboot), the Partition Manager will be used to partition the images instead of the device tree. It will go through the pm.yml files from all the child images and dynamically place the images, and eventually it will place the app where it's room left. Read the documentation for more information: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.9.1/nrf/scripts/partition_manager/partition_manager.html 

You can also set the partitions statically using a pm_static.yml file, for example like it's done in Other DFU samples, or in the maching learning application

Please let me know if anything is unclear

Best regards,

Simon