Hardware setting for MCP2515 SPI to CAN

As shown in the figure below, when used with raspberry pi or CM4, we need to push the switch to the top, and when used with CB1, we need to pull the switch to the bottom.

Software Settings

Work with raspberry pi

• Add the following to the raspberry pi /boot/config.txt file

  dtparam=spi=on
  dtoverlay=mcp2515-can0,oscillator=12000000,interrupt=24,spimaxfrequency=10000000

  and restart raspberry pi

Work with CB1

1. If the OS image of v2.2.1 version is used, the following dtb files need to be updated for stable use. If the OS image after V2.2.1 is used, this operation is unnecessary.
   • Download sun50i-h616-biqu.dtb
   • Replace /boot/dtb/allwinner/sun50i-h616-biqu.dtb in the OS with the downloaded sun50i-h616-biqu.dtb.
     
2. Uncomment overlays=mcp2515 in /boot/BoardEnv.txt.
   
   

Getting started

• Input the dmesg | grep -i '\(can\|spi\)' command to test whether MCP2515 has been connected normally after the restart is completed.
  The normal response should be as follows

  [ 8.680446] CAN device driver interface
  [ 8.697558] mcp251x spi0.0 can0: MCP2515 successfully initialized.
  [ 9.482332] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready

  
  

• Input sudo nano /etc/network/interfaces.d/can0 command to create a new file named can0, and write the following content

  auto can0
  iface can0 can static
      bitrate 500000
      up ifconfig $IFACE txqueuelen 1024

  Set the Canbus speed to 500K (consistent with the speed set in klipper), and set the txqueuelen to 1024 bytes. Save(Ctrl + S) and Exit(Ctrl + X) after modification, input sudo rebootto restart host

• Each micro-controller on the CAN bus is assigned a unique id based on the factory chip identifier encoded into each micro-controller. To find each micro-controller device id, make sure the hardware is powered and wired correctly, and then run:
  ~/klippy-env/bin/python ~/klipper/scripts/canbus_query.py can0
  If uninitialized CAN devices are detected the above command will report lines like the following:
  Found canbus_uuid=0e0d81e4210c
  set the correct ID number in printer.cfg
  

  [mcu EBB]
  canbus_uuid: 0e0d81e4210c