On 4/25/07, Thomas C. Sefranek <tcs@cmcorp.com> wrote:
> Hi Group,
> Is there anyone out there with a working knowledge of the CAN bus and the
> 18F4585?
>
>   I have it working with 25 nodes, but it has some Curious failures about
> .25% of the time. (Extended messages, null messages...)
> It looks like unresolved collisions in messages.
> I've tried lower baud rates and still have the problem.
>
> I'm using 122 ohm twisted pair, terminated at both ends.
> The signals look good on a "scope" at 1 megabaud.
>
> Tom


Have you checked the errdata?

+Under specific conditions, the first five bits of a
+transmitted identifier may not match the value in
+the Transmit Buffer ID register, TXBnSIDH. The
+following conditions must exist for the corruption to
+occur:
+1. A transmit message must be pending.
+2. The ECAN module must detect a Start-of-
+Frame (SOF) in the third bit of interframe
+space.

May be the problem.  In my setups I have seen this as random id's from
time to time.  Never seen it using the non ECAN mode.

/Ake





>
>   *
>   |  __O    Thomas C. Sefranek  WA1RHP@ARRL.NET
>   |_-\<,_   Amateur Radio Operator: WA1RHP
>   (*)/ (*)  Bicycle mobile on 145.41MHz PL74.4
>
> ARRL Instructor, Technical Specialist, VE Contact.
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>
>
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