Cargo Features

STM32F30X has no features set by default.

[dependencies]
stm32f30x = { version = "0.8.0", features = ["rt", "cortex-m-rt"] }
rt

Enables device of cortex-m-rt ^0.6.5

Features from optional dependencies

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

cortex-m-rt implicit feature

Enables cortex-m-rt ^0.6.5