Re: Acknowledging messages with SocketCAN

Re: Acknowledging messages with SocketCAN

[Marc Kleine-Budde]

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Hello Mike,

please use the linux-can mailinglist (Cc'ed)

On 06/04/2013 06:21 PM, Mike Mogenson wrote:
> First, thank you for your project.  

I'm just one of the developers working on this project, you're welcome.

> Second, I'm using your can-utils on a BeagleBone running Ubuntu with the
> 3.2 kernel.  Everything is working well with my can0 device in loopback
> mode.  However, when I connect a CAN enabled motor controller to the
> CANbus, the BeagleBone doesn't appear to acknowledge the motor
> controller's heartbeat message and the motor controller retries its
> message over and over.

It's normal behaviour that a CAN node repeats the message if it is not
acked on the bus.

> I don't see anything with candump or in
> /proc/net/can/stats, but I can see the message repeating over and over
> with an oscilloscope on the CANbus.

Ensure that your CAN network is properly terminated on both ends (120 Ohms).

Configure the bitrate of your d-can correctly, it must be the same as
the bitrate of your motor. With canutils:

    canconfig can0 bitrate 1250000

or iproute2's ip (the "ip" from busybox doesn't work):

    ip link set can0 type can bitrate 125000

Then activate your CAN:

    ifconfig can0 up

> Do I have to configure SocketCAN on the BeagleBone
> to acknowledge messages?  How can I set the BeagleBone to have a
> specific Node ID?  To my knowledge, the heartbeat message is not
> directed at a specific Node ID, but I will eventually need to direct
> messages from CAN devices to the BeagleBone.

regards,
Marc

-- 
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