* certain CAN frames not being read ok
@ 2012-05-22 0:37 Michael Economides
2012-05-22 16:56 ` Wolfgang Grandegger
0 siblings, 1 reply; 2+ messages in thread
From: Michael Economides @ 2012-05-22 0:37 UTC (permalink / raw)
To: Oliver Hartkopp, linux-can@vger.kernel.org
Hello,
I am reading CAN frames using read()
nbytes = read(s, &rframe, sizeof(rframe));
Sometimes it works fine. For example these frames are read ok:
123#44 33 33 33 33 33 33 44
112#05 01 01 01 22 22 33 33
However, this frame causes an "Ack slot" error:
123#01 00 00 00 00 00 00 00
Any ideas what could cause this?
I don't see why same ID but different data should cause a problem.
Thanks,
Mike
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: certain CAN frames not being read ok
2012-05-22 0:37 certain CAN frames not being read ok Michael Economides
@ 2012-05-22 16:56 ` Wolfgang Grandegger
0 siblings, 0 replies; 2+ messages in thread
From: Wolfgang Grandegger @ 2012-05-22 16:56 UTC (permalink / raw)
To: Michael Economides; +Cc: Oliver Hartkopp, linux-can@vger.kernel.org
On 05/22/2012 02:37 AM, Michael Economides wrote:
> Hello,
>
> I am reading CAN frames using read()
>
> nbytes = read(s, &rframe, sizeof(rframe));
>
> Sometimes it works fine. For example these frames are read ok:
>
> 123#44 33 33 33 33 33 33 44
> 112#05 01 01 01 22 22 33 33
>
> However, this frame causes an "Ack slot" error:
>
> 123#01 00 00 00 00 00 00 00
>
> Any ideas what could cause this?
This could be due to hardware problems on the CAN bus. Please check:
- bittiming.
- bus termination.
What does "candump -e any,0:0,#FFFFFFFF" report while you receive data?
And what CAN hardware are you using (what does "ip -d -s link show can0"
report)?
Wolfgang.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2012-05-22 16:56 ` Wolfgang Grandegger
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