Custom board and multiple revisions - how to

[Geir Strand]

Hi,

I have followed the steps on how to create a custom board for the nRF5340 according to the documentation here -> https://docs.zephyrproject.org/latest/hardware/porting/board_porting.html

Basically, I have copied the DevKit board folder and modified the files containing the pin definitions.
I am now in the process of making a new board, and want to use the board revisioning stuff as also shown in the Zephyr documentation. However, since there is only one overlay file, and the nRF5340 has 2 processors I run into the problem that I don't know for which processor the overlay is valid. To me it does not seem that Zephyr has support for this (yet). Any thoughts or suggestions?

Best regards,

Geir

[Øivind]

Hi,

The application core and the network core are considered as separate boards in the devicetree, each with their own devicetree, config and overlay files. If the image for the network core is built as a child_image of the application core image, you can add config fragments and overlay files for the network core image in a "child_image" folder in the project. These files should be named the same as the sample or project that the network core image is built from, for example "hci_rpmsg.overlay".

This section of the documentation explains how to set up your project folders for image-specific variables in multi-image builds: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/app_dev/multi_image/index.html#image-specific-variables

Please let me know if anything is unclear or if you run into any issues.

[Geir Strand]

Hi Øyvind,

I guess I wan't clear enough in with my question. 
I have a custom board, and we're making a revision of it. 
Zephyr board definitions support that one can make multiple revisions of the board. However, there is only one .overlay file per revision. 
With nRF5340 there is actually 2 CPUs in the nrf5340dk_nrf5340 board definition folder. Will the 4 different CPU definitions (cpuapp_ns, cpuapp, cpunet_ns and cpunet) be treated as individual definitions with its own revision, or will Zephyr treat the folder as a revision? 
Reason for asking is that my custom board has totally new pin definition, and it affects both the net core and app core. 
So, can I make 2/4 .overlays in the board definition folder, and zephyr will pick up changes to both net and app core pinning?

[Øivind]

Apologies for the late response. cpuapp_ns, cpuapp, cpunet_ns and cpunet are all considered as seperate boards, and would each need their own revision.