# `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

## Memory use

When in a tight memory situation and logging over RTT, the buffer size (default: 1024 bytes) can be configured with the `DEFMT_RTT_BUFFER_SIZE` environment variable. Use a power of 2 for best performance.

## 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