[eepro100] 82559ER MII

[Alexander Gdalevich]

Greetings to the board!

I am working on an embedded system porject using i82559ER ethernet 
controller.  We've ran into a few strange problems and so I am posting to 
this list trying to get some insight.

First problem is that for some reason I can't get the controller to operate 
in the loopback mode (our chip comes with the built-in i82555 Rev4 MII).  If 
I just set bit 14 of the MDI control register link status is up (bit 2 in 
MII Status register is high and I do read it twice) but frames sent in this 
mode never make it out on the wire, nor do they get looped back.  If I set 
loopback bit (bit 14 of MDI control) and try to restart autonegotiation the 
link stops operating (it is down until I disable loopback).

Does anyone know how to enable loopback?

Thanks.

Best wishes,

                           Alex.



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