pamoja-can

CAN bus framing for pamoja: classic CAN 2.0 and CAN-FD frames with 11-bit and 29-bit identifiers and the discrete CAN-FD length encoding, plus J1939 identifier decoding for trucks, tractors, and gensets, no_std and allocation-free. The framing half ahead of the CAN controller.

The same capability in every language

CAN bus framing for the pamoja SDK.

CAN is the bus that connects the moving parts of a machine: motor controllers, servos, battery management, and the engines, gensets, and farm equipment that speak J1939 on top of it. It is how a robot or a vehicle's pieces talk to each other reliably over a short, noisy two-wire link, which is why it is the SDK's path to actuators and to the diesel-and-hydraulic world of rural machinery.

This crate is the byte layer for that, with no controller and no allocation:

• CanId - a standard 11-bit or extended 29-bit identifier, always masked to width.
• Frame - a classic CAN 2.0 frame, a CAN-FD frame at the discrete CAN-FD lengths, or a remote frame, with len_to_dlc and dlc_to_len for the length encoding CAN-FD uses above eight bytes.
• J1939Id - the priority, parameter group, and addresses J1939 packs into a 29-bit identifier, decoded from one and composed back into one.

The controller hardware handles the wire itself (arbitration, bit timing, the frame CRC); this is the identifier and payload layer above it, the part an application actually reasons about. Driving a real controller arrives with the hardware-I/O layer.

Examples

use pamoja_can::{CanId, Frame, J1939Id};

// Build a classic frame for a motor controller.
let frame = Frame::new(CanId::standard(0x20A), &[0x01, 0xF4]).unwrap();
assert_eq!(frame.dlc(), 2);

// Decode an engine-speed broadcast from a J1939 genset.
let message = J1939Id::from_id(CanId::extended(0x0CF0_0400)).unwrap();
assert_eq!(message.pgn(), 61_444);
assert!(message.is_broadcast());

License

MIT - part of the pamoja workspace: one memory-safe Rust core with bindings for every language.