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Debugging ethernet PHY

Question asked by Elio Mussini on May 4, 2010
Latest reply on Jun 24, 2010 by David E Seymour

Hi, we have been trying for last few days to debug an ethernet link problem with a design based on the 52259 EVB.

Our design is using the same transceiver, magnetics and MII interface as seen in the EVB schematics, and of course the same PHY transceiver (DP83640).

The 52259 in our design can be flashed with no problems, and runs fine. We are testing with CW72 and the MQX3.5+RTCS stationary, but unfortunately we can not establish ethernet link between our design and the network.

The RTCS inits the 83640 part without any errors reporting, and it can bind to a static IP address with no problems, but our design wont reply to a ping from a different host, and of course our status leds are not showing ethernet link.

Looking at the DP83640 Datasheet, section11.4.5, Normal Link Pulse Detection/Generation, for 10BaseT in absence of link, the PHY is expected to send/look for 100ns pulses transmitted every 16ms.

The odd part is that our design is sending 16ms/50ns pulses instead. 

We think the problem is related to the pulse width, but not sure. As hard as we are trying, we are unable to identify the link problem, any ideas wolud be greately appreciated


Elio Mussini