Hi,

first of all: I have seen the thread that discusses the PHY-failure which 
normally happens very, very rarely.

Now my problem is: I have a relatively complex cape connected to my 
BeagleBone Black/Green. With this cape I see this PHY hardware 
initialisation failure quite often. It happens randomly but about once per 
four power-ups. I can bring back the PHY by pressing the reset-button, but 
in some (seldom) cases I have to reset the board up to 6 times. Resetting 
the AM3358 by software (by writing 0x00000002 to address 0x44E00F00) does 
not solve the problem. Here the SYS_RESETn should be pulled to LOW too, but 
it seems the time is not long enough for the PHY.

This behaviour is reproducible caused by my own cape: I tested it with 
several BeagleBone Black and Green, they all show this behaviour when 
connected to my cape but work properly when nothing is connected or when 
some other capes are plugged. During design of the cape I followed strictly 
the rules listed 
at http://elinux.org/Beagleboard:BeagleBoneBlack#Expansion_Header_Pin_Usage 
. And the problem appears in both cases, when the board us USB-powered only 
and when an external power supply is connected.

So my question: what could cause such a behaviour? What is the PHY 
sensisitve for?

I know, my information regarding the cape are quite inaccurate (because I 
can't give many details easily here), but any idea and any rough guess is 
welcome!

Paul

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