MPC860-T / FEC transmits each packet 3 times?

Wolfgang Denk wd at
Thu Nov 23 09:14:41 EST 2000


I'm struggeling with an Ethernet driver on the FEC of a MPC860-T.  To
the   best   of  my  knowledge,  I'm  doing  everything  strictly  as
documented, and as other drivers do it. However,  even  when  I  just
want to send a single packet (no interrrupts, everything as simple as
possible),  the package is sent 3 times to the wire; sometimes even 4
times. I don't see any indication of this in  the  software,  just  3
packets  on  the wire, usually 5...9 us apart (on a 100 Mbps net; the
packets come after 300...320 us on a 10 Mbps net).

Playing with half or full duplex mode didn't change anything. In case
it matters: it's a LXT972LC PHY. Ummm.. and yes, I can  be  sure  the
hardware is working OK. It does so in another OS...

Any ideas what I am missing?

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at
Imagination is more important than knowledge.      -- Albert Einstein

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