Secured Firmware Only?

[mansen motors]

There's a few threads out there with similar questions, but I haven't seen a direct answer to this.

If I build with nrf5340dk_nrf5340_cpuapp, can I use the entire application space (1MB) for my program? I realize I'm not using the security features here, but they are so complicated to implement and we have no need for them with our application, however we will run out of space if we are limited to the 256kB of secured flash space.

It's really not clear from the documentation if the application space is fixed in this configuration or not. Also, we'll need to use a bootloader at some point, will this still be possible?

[SwRa]

Hi Colin,

How much space you have for your application depends. The mcuboot uses around 48kB. So then you have roughly 1mb-48kb left for application. However, if you want dfu updates with two slots, then you have 1mb-48kb/2 left for the application (both applications slots need to have the same size). Also if you want to store stuff in flash, that will occupy space. If immutable bootloader is used, that will also occupy some space.

Regards,

Swathy

[mansen motors]

Hi Swathy, 

Thank you for the reply!

I understand that the total size depends on what partitions are chosen, I guess my real question wasn't clear enough, so:

Can you specify all the remaining flash (minus bootloader) to be used for a secured partition only. Or, is the secure partition limited to a specific size.

My question comes from a graphic I saw somewhere that I can no longer find which specified the Secure size to be 256kB and the non-secured to be the remaining flash. I'm starting to think this was just an example though.

My concern is over the peripheral access which is not granted in the non-secure partition. But I think it's starting to be clear from your response and my inability to ask the question, that what I found was just an example.

Thanks,

Colin