# `defmt-rtt` > Transmit [`defmt`] log messages over the RTT (Real-Time Transfer) protocol [`defmt`]: https://github.com/knurling-rs/defmt `defmt` ("de format", short for "deferred formatting") is a highly efficient logging framework that targets resource-constrained devices, like microcontrollers. The fastest way to get started with `defmt` is to use our [app-template] to set up a new Cortex-M embedded project. [app-template]: https://github.com/knurling-rs/app-template For more details about the framework check the book at https://defmt.ferrous-systems.com ## Support `defmt-rtt` is part of the [Knurling] project, [Ferrous Systems]' effort at improving tooling used to develop for embedded systems. If you think that our work is useful, consider sponsoring it via [GitHub Sponsors]. ## License Licensed under either of - Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0) - MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) at your option. ### Contribution Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be licensed as above, without any additional terms or conditions. [Knurling]: https://knurling.ferrous-systems.com/ [Ferrous Systems]: https://ferrous-systems.com/ [GitHub Sponsors]: https://github.com/sponsors/knurling-rs