[U-Boot-Users] SCC3 with very slow ethernet connection

Jerry Van Baren gerald.vanbaren at smiths-aerospace.com
Fri Mar 10 21:24:25 CET 2006

Franca, Jose Filipe (ext) wrote:
> Hello u all!
> 	I have a mpc8247 based board, with the following ethernet configuration:


> 	The result of this is a slow SCC3 ethernet connection. I've checked all the steps listed in the mpc8272 reference manual and everything seems to be by the book...
> 	From snifing around with ethereal, i've noticed that the frames seem to be passed nicely. But, sometimes there are some frames that aren't received and i get bit 11 asserted  (NO Rx nonoctet-aligned frame. Set when a frame containing a number of bits not divisible by eight is received. Also, the CRC check that occurs at the preceding byte boundary generated an error.). 
> 	What am i missing here?  Any ideas?
> 	Thanks a lot for reading! Many more if you reply :)
> Best regards,
> Filipe França.

Hardware problem?  Sounds like noise in the ethernet receive subsystem. 
  Do you have proper (impedance controlled and low noise) routing 
between the RJ-45, transformer, and the PHY?  Are the lines terminated 
properly at the transformer?


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