DESK-MX6UL-L/Pheripherals/CAN

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History
Version Issue Date Notes

1.0.0

Apr 2021 First DESK release
2.0.0 Mar 2022 DESK 3.0.0 release


Peripheral CAN[edit | edit source]

200px-Emblem-important.svg.png

The CAN peripheral is not available on AXEL ULite EVK. This peripheral is available on the i.MX6UL standard product SBCLynx

Device tree configuration[edit | edit source]

Here below an example of device tree configuration used on standard DAVE's kit for the AXEL ULite SOM:

From imx6ul-lynx-som0013-cb002f.dts:

&can1 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_flexcan1>;
    status = "okay";
};

From imx6ul-lynx-som0013.dtsi:

&iomuxc {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_hog_gpios>;

        imx6ul-lynx {
...
...
            pinctrl_flexcan1: flexcan1grp{
                    fsl,pins = <
                            MX6UL_PAD_LCD_DATA09__FLEXCAN1_RX       0x1b020
                            MX6UL_PAD_LCD_DATA08__FLEXCAN1_TX       0x1b020
                    >;
            };
};

Accessing the peripheral[edit | edit source]

Linux messages at boot time[edit | edit source]

...
...
[    3.806768] can: controller area network core
[    3.816080] can: raw protocol
[    3.819081] can: broadcast manager protocol
[    3.823309] can: netlink gateway - max_hops=1
...
...

Enable the interface and check status[edit | edit source]

root@desk-mx6ul-lynx:~# ip link set can0 type can bitrate 500000
root@desk-mx6ul-lynx:~# ifconfig can0 up
root@desk-mx6ul-lynx:~# ifconfig can0
can0: flags=193<UP,RUNNING,NOARP>  mtu 16
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 33

Usage with can-utils[edit | edit source]

root@desk-mx6ul-lynx:~# ip link set can0 type can bitrate 500000 triple-sampling on loopback on                                                                                                                 
root@desk-mx6ul-lynx:~# ifconfig can0 up
root@desk-mx6ul-lynx:~# candump can0 &
[1] 280
interface = can0, family = 29, type = 3, proto = 1
root@desk-mx6ul-lynx:~# cansend can0 -i 0x7ff 00 01 02 03 04 05 06 07
interface = can0, family = 29, type = 3, proto = 1
<0x7ff> [8] 00 01 02 03 04 05 06 07 
<0x7ff> [8] 00 01 02 03 04 05 06 07

Additional information[edit | edit source]

Each CAN port appears like a networking interface in the form canX where X is the port number.

Information about programming the CAN socket interface is given in the kernel tree under Documentation/networking/can.rst