Detecting CAN PHY Chip

Discussion in 'Troubleshooting' started by ctassell, Apr 10, 2015.

  1. ctassell

    ctassell UDOOer

    Apr 9, 2015
    Likes Received:
    Hi Everyone,

    I'm trying to get the CAN bus to work in Linux on the Udoo Dual and I'm not having any luck. I've got the kernel compiled and it boots fine, and I see the can0 network device, but I can't see any traffic. I'm wondering if there is a means to tell if the controller on the Udoo is actually talking to the PHY chip on the Arduino shield.

    On another note, I've seen references where you have to disable gpio8 in the Arduino IDE with "pinMode(69, INPUT)" to use CAN from the Linux side. Is that still required when using the patched kernel, or does the kernel patching reserve that pin for the iMX6?

    Here is the config of my can0 device, which looks the same whether the shield is plugged in or not.

    root@udoobuntu:~# ip -details -statistics link show can0
    2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
        can state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 
        bitrate 20000 sample-point 0.866 
        tq 3333 prop-seg 6 phase-seg1 6 phase-seg2 2 sjw 1
        flexcan: tseg1 4..16 tseg2 2..8 sjw 1..4 brp 1..256 brp-inc 1
        clock 30000000
        re-started bus-errors arbit-lost error-warn error-pass bus-off
        0          0          0          0          0          0         
        RX: bytes  packets  errors  dropped overrun mcast   
        0          0        0       0       0       0      
        TX: bytes  packets  errors  dropped carrier collsns 
        0          0        0       0       0       0    

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