DroneCAN

DroneCAN (formerly UAVCAN v0) is a lightweight protocol designed for reliable communication in aerospace and robotic applications over a CAN bus. INAV supports DroneCAN for connecting external sensors and peripherals such as battery monitors and GNSS receivers.

info

This page describes the INAV 10.0 (and later) DroneCAN implementation. DroneCAN sensor support is not present in the currently shipped 9.x firmware — the getting-started Hardware Overview still describes 9.x as not supporting DroneCAN sensors, which is correct for 9.x but stale for 10.0. That page is being updated separately; once the upstream fix lands, this qualification can be removed.

What DroneCAN gives you

A single CAN bus can carry multiple sensors and actuators to and from the flight controller. Peripherals broadcast on the bus, the flight controller listens, and configuration goes back the other way. This lets you:

• Replace a flight-controller ADC with a digital battery monitor that already measures both voltage and current, including per-cell data
• Use a remote GNSS receiver mounted away from RF noise without running a long serial cable
• Add and remove peripherals without re-flashing or re-wiring the FC

info

DroneCAN is independent of your serial-port configuration. It uses the CAN bus peripheral on the flight controller, which is separate from any UART.

Supported hardware

DroneCAN requires a flight controller with CAN bus hardware:

• STM32H7 boards (FDCAN peripheral)
• STM32F7 boards (bxCAN peripheral)

Check your flight controller's documentation to confirm CAN bus availability before connecting any DroneCAN peripherals.

Supported features

Feature	Status	Notes
GNSS receiver	Supported	Set gps_provider = DRONECAN
Battery voltage	Supported	Set vbat_meter_type = CAN
Battery current	Supported	Set current_meter_type = CAN
Per-node parameter Get/Set, Restart, Save	Supported	Configurator "DroneCAN" tab — requires INAV 10.0 or later
Dynamic Node Allocation (DNA)	Supported	Optional server; assigns node IDs automatically — requires INAV 10.0 or later
CAN bus-off event logging	Supported	New blackbox field droneCANBusOffCount — requires INAV 10.0 or later
ESC / actuator / RC-input over CAN	Not yet	Targeted for a future INAV release

Basic configuration

Open the DroneCAN tab in INAV Configurator to configure the flight controller on the bus — node ID, bitrate, and the DNA server toggle all live there. The same settings are also available via the CLI, which is useful for scripted setup or if the tab isn't available on your platform.

set dronecan_node_id = 1
set dronecan_bitrate_kbps = 1000
save

Setting	Values	Default	Description
dronecan_node_id	1-127	1	CAN node ID for the flight controller
dronecan_bitrate_kbps	125, 250, 500, 1000	1000	CAN bus bitrate in kbps; all peripherals must match
dronecan_use_dna_server	OFF, ON	ON	Whether the flight controller runs the Dynamic Node Allocation server (see Node management)

note

Node IDs 126 and 127 are reserved for network maintenance tools — avoid assigning them to your FC or peripherals.

Common next steps

After enabling DroneCAN on the bus, choose where each sensor's data should come from:

• For a DroneCAN GNSS receiver, see the GPS page.
• For a DroneCAN battery monitor (voltage and/or current), see the Battery Monitoring page.

Node management

info

This section describes behaviour available in INAV 10.0 and later, behind firmware PR #11683 and configurator PR #2671 (parameter Get/Set and the DroneCAN configurator tab), firmware PR #11688 and configurator PR #2672 (Dynamic Node Allocation), and firmware PR #11729 (CAN bus-off blackbox logging). It documents the intended user experience; behaviour may shift during review before these PRs merge.

INAV exposes DroneCAN nodes it can see on the bus through the INAV Configurator's DroneCAN tab. For each node you can:

• Read its identity (GetNodeInfo) — name, hardware/software version, unique ID
• Browse and edit its parameters (GetSet) — with the per-parameter min/max reported by the node itself, so out-of-range writes are rejected in the UI before they're sent
• Save parameters to the node's EEPROM (ExecuteOpcode(SAVE))
• Restart the node (RestartNode) — useful after firmware updates or when a peripheral is wedged

warning

The Restart button on a node restarts that node, not the flight controller. It is intentionally placed away from the global Save & Reboot button so the two cannot be confused.

Per-node restart caveat

Some peripherals acknowledge a RestartNode command and then reset themselves so quickly that their ACK frame never makes it onto the bus before the bus is gone. In that case the configurator will report "RestartNode failed" even though the node did in fact restart successfully. Confirm a successful restart by checking the node's NodeStatus heartbeats on the bus before assuming the restart was lost.

Dynamic Node Allocation

If you enable the DNA server (dronecan_use_dna_server = ON, the default), the flight controller assigns node IDs to peripherals that don't already have one configured. This means you can plug in a new DroneCAN peripheral and not have to manually configure its node ID first.

The DNA server:

• Honours a peripheral's preferred node ID where it can (within the available range, skipping already-allocated IDs)
• Stores its allocation table in persistent storage so the same peripheral gets the same node ID across power cycles
• Detects conflicts with actively-broadcasting nodes and reassigns rather than overwriting
• Reserves node IDs 126 and 127 for network maintenance tools and the FC's own ID range

If you prefer to assign every node ID manually, set dronecan_use_dna_server = OFF — or uncheck the toggle in the DroneCAN tab.

Blackbox logging

INAV exposes a cumulative bus-off event counter as a blackbox slow (S) frame field, droneCANBusOffCount. This lets you diagnose intermittent CAN bus faults from a recorded flight log without having to attach the configurator live and watch the dronecan CLI.

The field is gated behind USE_DRONECAN in the firmware and only appears in blackbox logs when DroneCAN is enabled on the target.

Bus wiring notes

DroneCAN requires a properly terminated CAN bus — termination at each physical end of the bus, not in the middle.

• Each flight controller and each peripheral should declare its own bus termination state in its documentation; verify both ends of the bus are terminated.
• A common cause of intermittent DroneCAN faults is missing or duplicated termination, which shows up in blackbox as an incrementing droneCANBusOffCount during the affected segment.
• Avoid running the CAN bus parallel to and close to RF sources (video transmitter, radio receiver with telemetry) — the bus is differential but shares the same physical space and can pick up noise.

Troubleshooting

If a peripheral isn't appearing in the configurator or isn't being seen by INAV:

• Verify the bitrate matches between the FC and all peripherals — the most common cause is a peripheral left at a different default bitrate from the FC
• Check the CAN wiring: CAN-H and CAN-L must not be swapped, both ends of the bus must be terminated, and the bus should have a common ground
• Check dronecan in the CLI for an active node count
• If you suspect bus-off events, decode a blackbox log and look at droneCANBusOffCount over time

For more detail on the protocol internals and the driver layer, see docs/DroneCAN.md and docs/DroneCAN-Driver.md in the INAV firmware repository.