embedded-hal-bus

embedded-hal-bus

Bus sharing utilities for embedded-hal, a Hardware Abstraction Layer (HAL) for embedded systems.

embedded-hal provides traits for SPI and I2C buses and devices. This crate provides hardware-independent adapters for sharing a single bus between multiple devices, compatible with the traits.

This project is developed and maintained by the HAL team.

SPI

To support bus sharing, embedded-hal provides the SpiBus and SpiDevice traits. SpiBus represents an entire bus, while SpiDevice represents a device on that bus. For further details on these traits, please consult the embedded-hal documentation.

embedded-hal trait implementations for microcontrollers should implement the SpiBus trait. However, device drivers should use the SpiDevice traits, not the SpiBus traits if at all possible in order to allow for sharing of the bus they are connected to.

This crate provides mechanisms to connect a SpiBus and a SpiDevice.

I2C

In the case of I2C, the same I2c embedded-hal trait represents either an entire bus, or a device on a bus. This crate provides mechanisms to obtain multiple I2c instances out of a single I2c instance, sharing the bus.

Optional Cargo features

• async: enable embedded-hal-async support.

• defmt-03: Derive defmt::Format from defmt 0.3 for enums and structs.

• alloc: enable implementations using alloc (for instance, spi::RcDevice, which makes use of alloc::rc::Rc)

• portable-atomic: Use portable-atomic to enable atomic-device on devices without native atomic CAS

  portable-atomic emulates atomic CAS functionality, allowing embedded-hal-bus to use atomic-device on hardware that does not natively support atomic CAS. If you enable this, you must also add portable-atomic to your crate with a feature flag such as unsafe-assume-single-core or critical-section to choose how atomic CAS is implemented. See https://docs.rs/portable-atomic/1.7.0/portable_atomic/#optional-features for more info.

• std: enable shared bus implementations using std::sync::Mutex.

Minimum Supported Rust Version (MSRV)

This crate is guaranteed to compile on stable Rust 1.60 and up. It might compile with older versions but that may change in any new patch release.

See here for details on how the MSRV may be upgraded.

Enabling the async Cargo features requires Rust 1.75 or higher.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (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 dual licensed as above, without any additional terms or conditions.