Library guide#

The m0601 crate is the driver the CLI is built on. Everything the command-line tool does, you can do from Rust — and the crate is written for exactly that, with a mock transport so you can test motor logic without hardware and a #![deny(unsafe_code)] budget it keeps to a single well-defended block.

Add the dependency#

By git:

[dependencies]
m0601 = { git = "https://github.com/dougcalobrisi/m0601-rs.git" }

Pin to something reproducible with rev, tag, or branch (defaults to main); cargo update -p m0601 moves a branch pin forward. Or work from a local checkout:

[dependencies]
m0601 = { path = "../m0601-rs/m0601" }

API shape#

Two types carry most of the work:

• M0601<T> is a handle to one motor: open, query, drive_velocity, drive_current, drive_position, set_mode, transact, safe_stop. Each drive_* call sends exactly one frame — the 50 Hz cadence is yours to provide.
• Bus<T> owns the shared serial port and hands out cheap, cloneable per-motor handles via bus.motor(id). It enforces frame spacing, runs group operations like safe_stop_all, and is what you reach for with more than one motor.

Supporting cast: Feedback and Telemetry for parsed replies, Mode and Faults for control state, PositionAccumulator for odometry, SlewLimiter for setpoint shaping, and the Transport trait — SerialTransport on hardware, MockTransport in tests.

Bus also carries the whole-bus operations the CLI is built from, so you rarely need to hand-build a frame: bus.scan(range, progress) returns a ScanReport { ids, garbled }, bus.set_id(new_id) performs the unaddressed rename, and send_raw (on either type) puts arbitrary bytes on the wire. Errors are one Error enum — Serial, Io, InvalidId, InvalidFrameLen, InvalidSlewRate — with is_permission_denied() for the dialout case.

The exhaustive surface is rustdoc’s job:

cargo doc --open -p m0601

The Ok(None) contract#

A silent bus is not an error. A motor that doesn’t reply — wrong ID, unpowered, a scan probe to an empty address — comes back as Ok(None), never Err. An Err always means the port or the OS failed. Handle the two distinctly; treating “no reply” as an exception will fight the whole API.

match motor.query()? {
    Some(fb) => { /* real telemetry */ }
    None     => { /* silence — expected, not a failure */ }
}

Pages#

They run in reading order, in four groups.

One motor — everything you need for a single wheel:

• Quickstart — read a motor without moving it.
• Drive loops — the 50 Hz cadence and safe_stop.
• Modes — velocity, current, position.

Reading the motor back:

• Telemetry — the two reply layouts and the accumulator that reconciles them.
• Odometry — PositionAccumulator and the aliasing bound on unwrapping a single-turn angle.

More than one motor:

• Multi-motor bus — sharing a bus, mirroring, spacing, group stops.
• Budgeting the wire — bus_period, frame_time, drive_floor: will N wheels fit in your cycle?

And once it’s yours to maintain:

• Testing without hardware — MockTransport, and the hardware-in-the-loop tests when you do have a motor.

For working code rather than snippets, see Sample code — four_wheel_minimal.rs is this whole guide in about fifty lines.

The snippets across these pages mirror m0601/examples/usage_doc_check.rs, which the CI compiles — so what’s shown here is known to build against the real API.