On 11/14/2010 04:26 PM, Willy Lambert wrote:
> Hi all,
>
> *The short story is :*
>
> I manage to use vcan0 but the same tests fails on my real can interface. I
> am not sure about my HW livelyness but I really don't know where to look at
> to see if everything is working.
>
> *The long one :*
>
> As I just found my way in the kernel modules, I'm am trying to send a
> message on my can bus. to begin smoothly, I loaded a vcan modules and tried
> cansend et candump with this script :
>
>> echo "Inserting can drivers..."
>> echo "insert can"
>> modprobe can
>> echo "insert can_raw"
>> modprobe can_raw
>> echo "insert can_bcm"
>> modprobe can_bcm
>> echo "insert vcan"
>> modprobe vcan
>>
>> echo "Configuring can ..."
>> ip link add dev vcan0 type vcan
>> ip link add dev vcan1 type vcan
>> ip link set up vcan0
>> ip link set up vcan1
>>
> And creates this can.log file :
>
>> (0.1) vcan0 5D1#0000
>> (0.2) vcan0 271#0100
>> (0.3) vcan0 289#72027000
>> (0.4) vcan0 401#081100000000
>>
>
> in one term I send :
>
>> ?>canplayer -l i -L can.log
>> in an other one I receive :
>> ?>candump vcan0
>>
>
> (by the way if someone could tell me how to configure vcan speed, if it is
> meaningfull)
It's *not* meaningfull. It's a *virtual* device.
> Then I tried the same thing with my real hardware using this script :
>
>> echo "Inserting can drivers ..."
>> modprobe can
>> echo "insert can_raw"
>> modprobe can_raw
>> echo "insert can_bcm"
>> modprobe can_bcm
>> echo "insert sja1000"
>> modprobe sja1000
>> echo "insert sja1000_isa"
>> insmod $MODPATH/drivers/net/can/sja1000/sja1000_isa.ko irq=5,7
>> mem=0xD0000,0xD0200
>>
>> echo "Configuring can drivers ..."
>> ip link set can0 type can bitrate 500000
>> ip link set can1 type can bitrate 500000
>> ip link set can0 type can restart-ms 10000
>> ip link set can1 type can restart-ms 10000
>> ifconfig can0 up
>> ifconfig can1 up
BTW: you could set everything with one command:
ip link set can0 up type can bitrate 500000 restart-ms 10000
> and uses the same commands after having changed "vcan0" into "can0" in my
> can.log file.
> As a result I have a full buffer error message (killing cansend) :
>
>> r...@alpha:/opt/ard# ../canplayer -l i -I can.log
>> sendto: No buffer space available
It seems that no can messages are going out to the bus, likely due to
electrical problems.
> Here, I am totally lost, I don't know what to look at, I don't event know if
> my can hw is running. Could someone ligth up my path ?
> I tried different configuration like :
> _ no cabling
Well, no comment.
> _ cabling can0 into can1
You mean connecting can0 and can1 to the same CAN bus/cable!?
> _ cabling on open can0
I don't understand!?
> I am not sure about my 120 Ohm resistors, I will check this on Monday, but
> as I am just trying to send is the real bus needed ?
Yes, you need a bus with a least one node responding to CAN messages.
Otherwise the bus error count of the device will increase and even reach
the bus-off state. The cable *must* be terminated with 120 Ohm at *each*
end of CAN bus cable.
> Here is some information I find relevant for analysis, I don't know what you
> need to look into my problem.
There a few tools and commands useful for debugging:
- List the CAN setting and statistics after sending a message:
# ip -d -s link show can0
# ip -d -s link show can1
- Dump real and error CAN messages while you send a message:
# candump any,0:0,#FFFFFFFF
Could you please show us the output of the above two commands.
Wolfgang.
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