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CAN Bridge

CAN bus is a serial communication protocol bus used for real-time applications, which can transmit signals using twisted-pair wires and is one of the most widely used field buses in the world. The CAN protocol is used for communication between various different components in a car, replacing expensive and cumbersome wiring harnesses. The robustness of the protocol has extended its use to other automation and industrial applications. Features of the CAN protocol include serial data communication with integrity, providing real-time support, transmission rates up to 1Mb/s, and having both 11-bit addressing and error detection capabilities. On 3D printers, CAN bus is used to reduce the number of wires connecting the print head to the motherboard; originally requiring over ten wires, with CAN only four wires are needed, significantly reducing the number of wires and lowering the wiring difficulty. This chapter briefly outlines the use of CAN bridging.

Tool Board Using CAN to Connect Motherboard​

  • Note that the power line of the tool board is not connected to the CAN port but to the 12V-24V power line.
  • Note that the 120Ω jumper must be connected.

Flashing the Motherboard Firmware​

  • Ensure that the firmware flashed on the D5 motherboard is USB bridge CAN firmware configuration.

Searching for ID​

  • If you need to use CAN, please ensure that your host computer has performed CAN configuration.
Note

Please ensure that the mainboard is properly connected to the host computer before proceeding with the following operations.

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Please ensure that the host computer's CAN network, the CAN rate of the bridge mainboard, and the CAN tool board rate are completely consistent.

  • Before searching for CAN IDs, please connect to SSH.
  • Please note that you must ensure you are logging into SSH via the network rather than via serial port.
  • Ensure that the UTOC is properly connected or the mainboard has been flashed with the CAN bridge firmware, and ensure that the data cable connecting to the host computer has data transmission capability.
  • Now that you have successfully logged into the host computer, you can enter lsusb to search for devices. This will result in one of the following scenarios:
    • If entering lsusb prompts that the ls command is not found, you can enter the following command to install the command: 
      sudo apt-get install usbutils
    • If entering lsusb results in no response, this indicates a system issue, and we are unable to assist. You need to change the system or use a confirmed normal system.
    • If the information shown below appears, please note that this is just a reference. You only need to confirm that 1d50:606f appears.
  • 1d50:606f belongs to the device you will be using. Ignore any subsequent prompts as system issues may cause it to display incompletely or not at all.
  • If there are multiple 1d50:606f, it is recommended to exclude one to avoid affecting subsequent firmware burning and connection to the firmware. For example, if it is FLY MINI PAD, it is recommended to use the onboard UTOC and not other CAN bridge devices.
  • If not, please check whether the data cable is properly connected and whether the firmware has been correctly flashed.
Note

You can only proceed with searching for CAN IDs when 1d50:606f is present.

  • Enter the following command to perform an ID search:
~/klippy-env/bin/python ~/klipper/scripts/canbus_query.py can0
  • If the ID appears and the Application: at the end shows Klipper, then this ID can be used directly.
  • If the ID appears and the Application: at the end shows CANBOOT or Katapult, then you need to flash the firmware to use it.

CAN Issue Collection​

Note
  • If you cannot find the CAN ID, please refer to the documentation below.
  • CAN Issue Collection

Fill in the CAN ID into the Configuration​

  • Open the printer web interface, find printer.cfg under the configuration options on the left sidebar: for fluidd {...}; for mainsail machine, click to enter, and you can find printer.cfg.

  • Copy the queried UUID and fill it into the [mcu] section of the canbus_uuid: in the printer.cfg configuration. After saving and restarting, you can connect to the mainboard. If Klipper prompts that firmware needs to be updated, ADC errors, etc., it indicates that Klipper has already connected to the mainboard.

    dangerous

    Note: All IDs appearing in the document are examples. The actual ID for each mainboard is different. Please modify and fill in according to the actual obtained ID.