Expand description
dcc-rs
Pure-Rust implementation of NMRA Digital Command Control
This crate implements the NMRA DCC protocol, intended for embedded use on e.g.
custom base stations for computer control. It is fully no_std
-compatible,
with zero allocations and uses the embedded_hal
traits for driving output
pins.
To work around the lack of standardised interrupt support, this crate provides
a DccInterruptHandler
struct which may be owned by a static
within an
interrupt handler, and the DccInterruptHandler::tick
method performs all of
the necessary processing, returning the number of microseconds to wait before
it should be called again. This timing is critical to the correct functioning
of this crate as it is used to time the output pin transitions.
Getting new data packets into the DccInterruptHandler
is left as an exercise
for the implementor. In the provided example code, it is done via a Mutex
holding a RefCell<Option<_>>
, which allows external code to pop new serialised
packets in for the interrupt handler to retrieve at its leisure.
Status
This crate currently only implements the base station (transmitter) side, and only the “baseline” and “service mode” packets. “Extended format” DCC packets are a work in progress.
DCC receiving is under future work, once the main packet types have been implemented.
Example implementations
- examples/stm32f103-blue-pill Single-channel speed controller
Contributing
Contributions are welcome, in the form of code improvements, testing reports,
more example implementations, more platform implementations, etc. I’m
particularly interested in getting this running on an arduino uno/nano once
the loose ends in Rust’s AVR support have been tidied up. A drop-in replacement
DCC++
-compatible firmware would also be neat.
Licence
This crate is available under the terms of the Mozilla Public Licence Version 2.0.
Re-exports
pub use bitvec;
Modules
Modules containing packet definitions
Structs
The main interrupt handler. Calling the tick
method advances the
internal state and toggles the provided output pin to control the
track polarity
Enums
Error types returned by this crate