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PX4 CAN Receive

Receive message from CAN network

  • Library:
  • UAV Toolbox Support Package for PX4 Autopilots

  • CAN Receive block

Description

The PX4 CAN Receive block receives messages from a Controller Area Network (CAN) network by using the PX4 Autopilot CAN port connected to the hardware.

Specify the message type and its properties using the block parameters dialog box.

If you simulate a model that contains the PX4 CAN Receive block without connecting the hardware, the block outputs zeros. For more information, see Block Produces Zeros or Does Nothing in Simulation.

Also, if there are no messages on the CAN bus, the block outputs zeros.

Note

To avoid conflict with PX4 UAVCAN, disable UAVCAN before working with PX4 CAN blocks. To disable, set the PX4 parameter, UAVCAN_ENABLE to 0. For more information, see Finding/Updating Parameters.

Limitations

  • PX4 CAN Receive blocks do not support Connected IO simulation.

  • All PX4 CAN Receive blocks must have the same Data is input as parameter.

    Ports

    Output

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    The block outputs messages in uint8 and CAN Msg format.

    • uint8 – To output the message as a uint8 vector array, select Data is output as to Raw data.

    • CAN Msg – To output the message in CAN message format, select Data is input as to CAN Msg. For more information, see Data is input as.

    Data Types: uint8 | CAN Msg

    The length of the message, in bytes.

    Data Types: uint8 | CAN Msg

    The port outputs the message received status.

    The port outputs one of these values:

    • 0 for a successful CAN receive.

    • 1 for a failure in opening the CAN.

    • 2 for a failure in setting Baud rate.

    • 3 for a failure in setting CAN Test mode.

    • 4 for a failure in CAN receive.

    Dependencies

    This port appears only when you select the Output Status parameter.

    Data Types: uint8

    The port sends request for remote frames.

    Dependencies

    This port appears only when you select the Output Remote parameter.

    Parameters

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    Select a type to receive message.

    • Raw data – To receive message as a 1-by-N uint8 array, select Data is input as to Raw data.

    • CAN Msg – To receive message in CAN message format, select Data is input as to CAN Msg and then perform these steps:

      1. Add a CAN Unpack block from the Embedded Coder® / Vehicle Network Toolbox™ to your model.

      2. Connect the output of the CAN Receive block to the input of the CAN Unpack block.

      3. Using the options in the Data is input as list of the CAN Unpack block, specify if you want to create your messages or you want to upload a CAN database file. If you choose to upload a CAN database file, the CAN Unpack inherits the message properties from the uploaded file.

      Note

      To use the CAN Unpack block, you must have a Embedded Coder / Vehicle Network Toolbox license.

    Message identifier, which is 11 bits long for the standard frame size or 29 bits long for the extended frame size, specified in decimal, binary, or hex. For binary and hex formats, use bin2dec(' ') and hex2dec(' '), respectively, to convert the entry. The message identifier is coded into a message that is sent to the CAN bus.

    Dependencies

    This parameter appears only when you select Data is input as to Raw data. To output the identifier of the CAN Msg, select Output identifier of the CAN Unpack block.

    The type of message identifier.

    Dependencies

    This parameter appears only when you select Data is input as to Raw data.

    Specify how often the block receives message, in seconds. When you specify this parameter as -1, Simulink® determines the best sample time for the block based on the block context within the model.

    When you select the Output Status parameter, the block configures an output port, Status. The port outputs the message remote frame status.

    When you select the Output Remote Flag parameter, the block configures an output port, Remote. The port outputs the message remote frame status.

    Dependencies

    This parameter appears only when you select Data is input as to Raw data.

    Version History

    Introduced in R2022b