danielzfranklin: ok, that is one possibility, how to check if they are incompatible ? this is my cargo.toml [dependencies] cortex-m = "0.7.3" cortex-m-rt = "0.7.0" rtt-target = {version = "0.3.1", features = ["cortex-m"] } panic-rtt-target = { version = "0.1.2", features = ["cortex-m"] } nrf52840-hal = { version = "0.14.0", features = ["rt"] } embedded-time = "0.12.1" [dependencies.embedded-hal] version = "0.2.3" features = ["unproven"]