CAN sampling point

Hi
I am using CAN communication between C2810 DSP and ARM. At high data rate such as 500 kps I am getting errornous packets. I want to know how to decide sampling point, is changing dtaa transfer speed requires change in sampling point.

Thank and Regards,
Ruturaj Devkar.

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ruturaj,

I cannot say about setting up the ARM processor (which the c2810 doesn't have) for CAN communications.

However, the manuals for the 2800 family of DSPs has the formulas and suggested sampling points for CAN communication.

There is even a set of documents at TI that describe exactly how to communicate with the CAN peripheral/bus, including all the specific register values to use.

You might also read the erata for the 2810 DSP. for reasons for failure of CAN communications.

I know, for the 2812, there are several failure modes that are all hardware related. Most of the fixes require a second read of the CAN data if the first read is '0' and similar handling for xmit data when accessing the CAN mailboxes because the CAN bus has priority over the CPU bus.

There are several 'error' status bits and the ability to have the CAN bus automatically retry when a xmit sequence does not return a 'success' indication.

Also, several of the registers, when a change is written to the register, require the software to loop, polling for the change to be completed, before continuing with the xmit or recv sequence.

R. Williams

---------- Original Message -----------
From: r...@dbups.co.in
To: c...
Sent: Wed, 27 Jan 2010 23:35:25 -0500
Subject: [c6x] CAN sampling point

>
>
> Hi
> I am using CAN communication between C2810 DSP and ARM. At high data rate such as 500 kps I am getting errornous packets. I want to know how to decide sampling point, is changing dtaa transfer speed requires change in sampling point.
>
> Thank and Regards,
> Ruturaj Devkar.
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