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.
This crate currently only implements the base station (transmitter) side, and only the basic "speed and direction" packet. Other DCC packets are a work in progress. DCC receiving is under future work, once the main packet types have been implemented.
This crate is available under the terms of the Mozilla Public Licence Version 2.0.