readme.md

Devicetree semantics

This Zephyr freestanding application is used in the fourth article of the "Practical Zephyr" series. The application itself is just a dummy but shows important Devicetree API macros. The most important files are the Devicetree overlay files and Devicetree bindings:

• props-basics.overlay shows all basic types except for phandles. The matching bindings can be found in custom-props-basics.yaml
• props-phandles.overlay shows the phandle, phandles, and phandle-array types. The matching bindings can be found in custom-props-phandles.yaml, and the bindings for the specifier cells used in the phandle-array are defined in custom-cells-a.yaml and custom-cells-b.yaml.

In addition, this application demonstrates three overlay files that are picked up automatically when building for Nordic's nRF52840 development kit:

• app.overlay
• nrf52840dk_nrf52840.overlay
• boards/nrf52840dk_nrf52840.overlay

The following command can be used to build the application:

west build --board nrf52840dk_nrf52840 --
    -DEXTRA_DTC_OVERLAY_FILE="dts/playground/props-phandles.overlay;dts/playground/props-basics.overlay"

The goal of this application is to demonstrate Devicetree bindings and thus the macros produced by Zephyr's Devicetree generator script in build/zephyr/include/generated/devicetree_generated.h. The main.c application shows the basic use of the Devicetree API macros.

Note: The tasks.py script is used by the GitHub action for building this application using invoke.