[U-Boot-Users] LXT971A PHY debugging on MPC8540 Custom Board

Gerhard Jaeger g.jaeger at sysgo.com
Tue Jun 14 08:39:47 CEST 2005

On Monday 13 June 2005 19:55, Shirasat Girish-ags032 wrote:
> Hi ,
>    I have partially ported Uboot on one of our MPC8540 based custom boards.
> I am currently facing problems in bringing up the 10/100Mbps FEC 
> interface. We are using the LXT971A PHY for the FEC interface.
> Well the problem is that , the MAC is putting out the data but the PHY is
> failing to put the data on the line. The PHY is successfully able to auto-
> negotiate. The MAC putting out data was confirmed by the MAC debug 
> registers and by probing the Tx_EN,clock and TX_D lines.
>    I  carried out the MAC loop back test which passed . Then went on
> for the PHY internal loop back test. Well, when the loop back is enabled the
> MAC fails to transmit the frame successfully. The thing confusing me is that
> why the MAC frame transmission is getting affected when i enable the PHY
> loopback test.
>  Any pointers will be very helpful.
> Regards,
> Girish

as I'm also doing some work on a custom MPC8540 board with a LTX971, I noticed,
that the register definitions and masks for the status-register 2 in
cpu/mpc85xx/tsec.h are wrong, maybe this has also something to do with your
problem! The attached patch fixes that. 

Maybe Wolfgang will also put that to CVS, as this is an obvious bug!


Gerhard Jaeger <gjaeger at sysgo.com>            
SYSGO AG                      Embedded and Real-Time Software
www.sysgo.com | www.elinos.com | www.pikeos.com | www.osek.de 
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