Cargo Features

LPC43xx has no features set by default.

lpc43xx = { version = "0.1.0", features = ["rt"] }
rt = cortex-m-rt

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

cortex-m-rt rt?

Enables cortex-m-rt ^0.5.1