Thread (16 messages) 16 messages, 5 authors, 2017-08-10

Re: [PATCH v2 2/4] can: fixed-transceiver: Add documentation for CAN fixed transceiver bindings

From: Oliver Hartkopp <socketcan@hartkopp.net>
Date: 2017-07-28 08:41:51
Also in: linux-can, linux-devicetree, lkml

On 07/28/2017 06:57 AM, Kurt Van Dijck wrote:
So while _a_ transceiver may be spec'd to 1MBit during arbitration,
CAN FD packets may IMHO exceed that speed during data phase.
When the bitrate is limited to 1Mbit/s you are ONLY allowed to use 
1Mbit/s in the data section too (either with CAN or CAN FD).
That was the whole point of CAN FD: exceed the limits required for
correct arbitration on transceiver & wire.
No. CAN FD is about a different frame format with up to 64 bytes AND the 
possibility to increase the bitrate in the data section of the frame.
So I do not agree on the single bandwidth limitation.
The transceiver provides a single maximum bandwidth. It's an ISO Layer 1 
device.
The word 'max-arbitration-bitrate' makes the difference very clear.
I think you are mixing up ISO layer 1 and ISO layer 2.

Regards,
Oliver
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