Re: About bittiming calculation result

From: Wolfgang Grandegger
Date: Tue Feb 08 2011 - 02:55:23 EST


Hi Tomoya,

On 02/08/2011 02:27 AM, Tomoya MORINAGA wrote:
> On Tuesday, February 08, 2011 12:53 AM, Wolfgang Grandegger wrote:
>
>> BTW, it's always possible to specify optimized bit-timing
>> parameters directly, e.g. the following seem better:
>>
>> 800000 60 12 4 4 4 3 793650 0.8% 80.0% 81.0% 1.2%
>>
>> You could set these with:
>>
>> $ ip link set can0 type can \
>> tq 60 prop-seg 12 phase-seg1 4 phase-seg2 4 sjw 4
>
> I can confirm 800K comms works well using the above.

Cool, I got these magic values from a CAN hardware expert.

> I wish Can-core could calculate like above.

Me too! I also got some indication on how to improve our algorithm in
case the bit-rate does not match. Hope to find some time soon to work
on this issue.

>>> seg1/seg2/sjw/prop_seg must be more than 1 ?
> BTW, according to EG20T PCH data sheet,
> CAN bit-timing parameters(BRP, Prop_Seg, Phase_Seg1, Phase_Seg2, SJW) must not be set 0.

OK, then please provide a patch setting tseg1_min to 2.

Wolfgang.
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