Subject: Re: 8260 Communications Proccessor overload??

From: Dan Malek <[email-masked]>
Date: Wed, 10 Oct 2001 14:02:49 -0400

Kevin Fry wrote:
>
>    Has anyone ever run all 3 FCC ports at the same time with a
> 100Mbit link?

Yeah.....

> ....  I think I'm seeing the Communications Processor get
> overloaded, but Motorola claims there is no problem.

What clock speeds are you running?  Are they full or half duplex
connections?

> the Ethernet PHY (AM79C874) indicates no errors, but the MAC is
> reporting
> CRC errors.

Hmmm...Do you ever see any buffering problems on the Linux driver
side, like the CPU can't keep up with the data?

> .... I have captured the MAC --> PHY transfers on a logic
> analyzer
> and am decoding them at present (I hate computing a CRC-32 by hand).  I
> was
> hoping someone else has experience relative to this situation.

I have seen some noise problems with some boards between the MAC and
PHY.  Some crappy looking layouts worked great, some really pretty
ones had trouble :-).  I don't know if this would be represented as
a CRC error or something else.

Good Luck!  Keep us posted :-).

	-- Dan

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