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Orange Pi Zero 3 – CAN FD

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Used image: Orangepizero3_1.0.4_debian_bookworm_server_linux6.1.31

Software needed:

sudo apt install -y can-utils

In this example we are using a MCP2518 SPI CAN controller and a ISO1042 Isolated CAN transciever for CAN 2.0B Classic communication on a Orange Pi Zero

Icoon

MCP2518FD datasheet (Microchip).pdf #

1 bestand(en) 1.12 MB
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Icoon

SN65HVD23x datasheet (Texas Instruments).pdf #

1 bestand(en) 1.20 MB
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Connection schematic:

MCP2518 Overlay #

To use the MCP2515 we first need to create an overlay for the IO pins:

sudo nano /boot/dtb/spi-mcp251x.dts

Contents:

/*
 * Device tree overlay for mcp2517/18 @ can0 on SPI1.1 (Orange Pi Zero 3)
 */

 /dts-v1/;
 /plugin/;

 / {
     compatible = "allwinner,sun50i-h616";

     fragment@0 {
         target-path = "/";
         __overlay__ {
             can0_osc_fixed: can0_osc_fixed {
                 compatible = "fixed-clock";
                 #clock-cells = <0>;
                 clock-frequency = <20000000>;
             };
         };
     };

     fragment@1 {
         target = <&pio>;
         __overlay__ {
             can0_pin_irq: can0_pin_irq {
                 pins = "PC7";
                 function = "irq";
                 bias-pull-up;
             };
         };
     };

     fragment@2 {
         target = <&spi1>; /* Use SPI1 */
         __overlay__ {
             #address-cells = <1>;
             #size-cells = <0>;
             mcp2518fd@1 {
                 compatible = "microchip,mcp2518fd";
                 reg = <1>; /* Use SPIx.1 */
                 pinctrl-names = "default";
                 pinctrl-0 = <&can0_pin_irq>;
                 spi-max-frequency = <10000000>;
                 interrupt-parent = <&pio>;
                 interrupts = <2 7 0x08>; /* PC7 IRQ_TYPE_LEVEL_LOW */
                 clocks = <&can0_osc_fixed>;
                 status = "okay";
             };
         };
     };
 };

Please note:

  • SPI 1.1 is used
  • Interrupt (INT) is PC7
  • Clock is 20Mhz

If you have used another crystal/resonator (e.g. 40 MHz), please adjust the value above ‘clock-frequency = <40000000>;‘

Add the overlay to the system:

sudo dtc -I dts -O dtb -o /boot/dtb/allwinner/overlay/sun50i-h616-spi-mcp251x.dtbo /boot/dtb/spi-mcp251x.dts

The overlay should compile and added withouth any errors

Set hardware interfaces #

To enable the overrlay and set the SPI hardware settings:

sudo nano /boot/orangepiEnv.txt

add after overlay_prefix:

overlays=ph-i2c3 ph-uart5 spi0-spidev spi1-cs1-spidev spi-mcp251x
param_spidev_spi_bus=0
dtparam=spi=on

Enable in network interface #

To enable CAN in the network interface edit the network interfaces file:

sudo nano /etc/network/interfaces

add at the end (example shows 250kbit abitration rate and 500kbit datarate:

auto can0
iface can0 inet manual
    pre-up /sbin/ip link set can0 type can bitrate 250000 dbitrate 500000 fd on restart-ms 100
    up /sbin/ifconfig can0 up
    down /sbin/ifconfig can0 down

Now reboot:

sudo reboot

Check hardware #

After reboot check the hardware, is the chip succefuilly initialised?

dmesg |grep mcp

Should output:

[ 1733.045547] mcp251xfd spi1.1 can0: MCP2518FD rev0.0 (-RX_INT -PLL -MAB_NO_WARN +CRC_REG +CRC_RX +CRC_TX +ECC -HD o:20.00MHz c:20.00MHz m:10.00MHz rs:8.50MHz es:6.00MHz rf:8.50MHz ef:6.00MHz) successfully initialized.

If you got this error, then check your wiring!, you can use modprobe to check SPI again:

sudo modprobe -r mcp251xfd
sudo modprobe mcp251xfd

Check if CAN adapter is in the network tree:

sudo ifconfig can0

Output:

can0: flags=193<UP,RUNNING,NOARP>  mtu 72
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 591393  bytes 35896384 (34.2 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2347  bytes 18692 (18.2 KiB)
        TX errors 0  dropped 47 overruns 0  carrier 47  collisions 0
        device interrupt 68

CAN 2.0B Classic change baudrate #

You can change baudrate this way, first turn off the can0 interface:

sudo ip link set can0 down

Then enable the can0 interface again with the desired baudrate example 500kbit:

sudo ip link set can0 up type can bitrate 500000

DMESG errors

To prevent format errors (wich you cannot suppress)

[ 2552.869113] mcp251xfd spi1.1 can0: CRC write command format error.

you can start with “fd off”

sudo ip link set can0 up type can bitrate 500000 fd off

CAN FD Classic change baudrate #

You can change baudrate this way, first turn off the can0 interface:

sudo ip link set can0 down

Then enable the can0 interface again with the desired ARBITRATION bitrate of 250kbit and a DATA bitrate 500kbit as example:

sudo ip link set can0 up type can bitrate 250000 dbitrate 500000 fd on

Recieve CAN data #

To check recieved dat you can use candump:

sudo candump can0

Example output:

  can0  63E  [64]  00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14
15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F
30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
  can0  3A2  [64]  00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14
15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F
30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
  can0  10E  [64]  00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14
15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F
30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F

To see RX/TX you can use:

candump -x can0


Example output:

  can0  RX B -  712  [64]  00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12
13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E
2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
  can0  RX B -  49C  [64]  00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12
13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E
2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
  can0  RX B -  1FE  [64]  00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12
13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E
2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
  can0  RX B -  786  [64]  00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12
13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E
2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F

if you have 2 canbus interfaces you may want to add color:

candump -x -c can0

Filter data

To filter data e.g. a specific ID, you can use for example ID 11:

candump -x can0,011:7FF

Send CAN data #

You can send CAN data by using cansend [ID]#[MESSAGE], example

sudo cansend 003#010203FDFF

System load #

We have tested the Orange Pi Zero 3 system load with an ESP32 on “full blast” 64 byte CAN messages.

Result :6.9% system load on SPI1.1 with 250kbit speed:

Result :12.5% system load on SPI1.1 with 500kbit speed: