Cargo Features

nrf5340-app-pac has no features set by default.

[dependencies]
nrf5340-app-pac = { version = "0.12.2", features = ["rt", "cortex-m-rt"] }
rt

Enables device of cortex-m-rt

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features.

cortex-m-rt implicit feature