# PX4 Instructions Find most up to date documentation at ARK CANnode runs the [PX4 DroneCAN Firmware](https://docs.px4.io/main/en/dronecan/px4_cannode_fw.html). As such, it supports firmware update over the CAN bus and [dynamic node allocation](https://docs.px4.io/main/en/dronecan/#node-id-allocation). ## CANnode Firmware ARK CANnode boards ship with recent firmware pre-installed, but if you want to build and flash the latest firmware yourself see [PX4 DroneCAN Firmware > Building the Firmware](https://docs.px4.io/main/en/dronecan/px4_cannode_fw.html#building-the-firmware). #### Building the Application ``` make ark_cannode ``` #### Building the Bootloader ``` make ark_cannode_canbootloader ``` #### Flashing the Bootloader To flash the bootloader firmware you need an ST-LINK programmer. See the [ST-LINK Flashing Guide](/knowledge-base/knowledge-base/st-link-flashing-guide.md) for setup instructions. ``` st-flash write 0x08000000 ``` #### Flashing the Application To flash the application firmware you can use the SD card method as [documented here](https://docs.px4.io/main/en/dronecan/#firmware-update) or you can use the DroneCAN GUI Tool and a USB-to-CAN adaptor to flash the firmware directly. ## Configuration Connect the ARK CANnode to the flight controller's CAN bus using a standard 4-pin JST-GH cable. DroneCAN configuration in PX4 is explained in more detail in [DroneCAN > Enabling DroneCAN](https://docs.px4.io/main/en/dronecan/#enabling-dronecan). ### Flight Controller Parameters Set the following in *QGroundControl* and reboot the flight controller. #### Required | Parameter | Value | Description | | ---------------------------------------------------------------------------------------------------- | ----- | --------------------------------------------------------------------------------------------------------------------------------- | | [UAVCAN\_ENABLE](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_ENABLE) | 2 | Enable DroneCAN with dynamic node allocation. Set to `3` if using [DroneCAN ESCs](https://docs.px4.io/main/en/dronecan/escs.html) | #### Optional Enable a `UAVCAN_SUB_*` subscriber for each sensor connected to the ARK CANnode. The onboard IMU subscriber is listed below; for other sensors (airspeed, barometer, etc.), see the parameters named `UAVCAN_SUB_*` in the [PX4 parameter reference](https://docs.px4.io/main/en/advanced_config/parameter_reference.html). | Parameter | Description | | ------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- | | [UAVCAN\_SUB\_IMU](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_SUB_IMU) | Set to `1` to subscribe to DroneCAN `RawIMU` messages from the onboard IMU. Requires `CANNODE_PUB_IMU` to also be set on the ARK CANnode | ### CAN Node Parameters Set the following on the CANnode and reboot the node. CAN node parameters can be configured using either: * [QGroundControl](https://docs.px4.io/main/en/dronecan/#qgc-cannode-parameter-configuration) — each CAN node appears as a separate *Component X* entry under **Vehicle Settings > Parameters**. * The [DroneCAN GUI Tool](/knowledge-base/knowledge-base/dronecan-gui-tool-guide.md). #### Optional | Parameter | Description | | --------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | | [CANNODE\_TERM](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#CANNODE_TERM) | Set to `1` if this is the last node on the CAN bus | | [CANNODE\_PUB\_IMU](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#CANNODE_PUB_IMU) | Set to `1` to publish `RawIMU` messages from the onboard ICM-42688-P IMU on the CAN bus. Requires `UAVCAN_SUB_IMU` to also be set on the flight controller | ## CANnode as PWM Expander The ARK CANnode can be used as a PWM Expander over CAN, allowing you to drive additional servos or ESCs from the flight controller. ### Common Setup Regardless of whether you are using servos or ESCs, the following flight controller parameters must be configured: ``` UAVCAN_ENABLE 3 # Sensors and Actuators (ESCs) Automatic Config UAVCAN_PUB_ARM 1 # Required to publish arming state to CANnode ``` On the CANnode, set the timer output protocol using `PWM_MAIN_TIMx` parameters. You can see the timer-to-output mapping here:\ ### Servos For servo outputs, we recommend using standard 50Hz PWM. Set the timer protocol to 50Hz on the CANnode: ``` PWM_MAIN_TIM0 50 ``` #### Flight Controller Parameters ``` UAVCAN_EC_FUNC1 201 # Servo 1 UAVCAN_EC_FUNC2 202 # Servo 2 UAVCAN_EC_FUNC3 203 # Servo 3 UAVCAN_EC_FUNC4 204 # Servo 4 ``` #### CANnode Parameters Using the DroneCAN GUI Tool or QGroundControl, configure the parameters to map your PWM outputs: ``` PWM_MAIN_FUNC1 201 # Servo 1 PWM_MAIN_FUNC2 202 # Servo 2 PWM_MAIN_FUNC3 203 # Servo 3 PWM_MAIN_FUNC4 204 # Servo 4 ``` You can also optionally adjust the min, max, and disarmed values: ``` PWM_MAIN_DIS1 1500 PWM_MAIN_MIN1 1000 PWM_MAIN_MAX1 2000 ``` ### ESCs For ESC outputs, we recommend using DShot300. Set the timer protocol on the CANnode: ``` PWM_MAIN_TIM0 -4 # DShot300 ``` {% hint style="info" %} PWM over CAN update rate is limited to 400Hz, so it is recommended to keep ESCs on the flight controller's outputs if possible. {% endhint %} #### Flight Controller Parameters ``` UAVCAN_EC_FUNC1 101 # Motor 1 UAVCAN_EC_FUNC2 102 # Motor 2 UAVCAN_EC_FUNC3 103 # Motor 3 UAVCAN_EC_FUNC4 104 # Motor 4 ``` #### CANnode Parameters Using the DroneCAN GUI Tool or QGroundControl, configure the parameters to map your PWM outputs: ``` PWM_MAIN_FUNC1 101 # Motor 1 PWM_MAIN_FUNC2 102 # Motor 2 PWM_MAIN_FUNC3 103 # Motor 3 PWM_MAIN_FUNC4 104 # Motor 4 ``` You can also optionally adjust the min, max, and disarmed values: ``` PWM_MAIN_DIS1 1000 PWM_MAIN_MIN1 1100 PWM_MAIN_MAX1 1900 ``` {% hint style="info" %} Bidirectional DShot on the CANnode is not yet supported. {% endhint %} #### DShot Telemetry When using DShot you can also receive ESC telemetry via UART from the Telem pin of the ESC. Connect the Telem pin from the ESC to the USART1\_RX pin of the[ UART1/I2C port](https://arkelectron.gitbook.io/ark-documentation/sensor/ark-cannode#uart1-i2c1-6-pin-jst-gh) of the CANnode. Set the **DSHOT\_TEL\_CFG** parameter on the CANnode to 201. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.arkelectron.com/products/sensor/ark-cannode/px4-instructions.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. 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