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FEC: Gives rx frame interrupts but no data ..

Question asked by vespaman on Oct 20, 2009
Latest reply on Oct 23, 2009 by vespaman

I have this issue with the FEC in 52259, where, after I have set it up (using example code from freertos/lwip), it does cannot receive anything.


I get the rx frame interrupts, which is what I have set-up, but if I look in the descriptor, RX_BD_E is still set, the length is left unchanged from my default.


I have checked all (4 in my case) rx descriptors, but all are as initiated from start. MCF_FEC_ERDSR is, if I read from it, set to the same address as the first descriptor.

All aligned using the run-time alignment method seen in most examples, to 16 bytes.


This is not my first project using the FEC  (used it in the 5280 before), still I am lost. I have double checked everything, and really, the example should work out of the box more or less.


So, is there anything obvious I have missed? Is there any condition that can make the FEC give the RX_FRAME interrupt, but leaving the rx descriptors untouched?


As far as I can understand, 52259 does not support data cache, so I think it is not a cache issue.

I have tried to connect it to a 10mbit hub as well as the gigabit switch we use here, with the same outcome. If I unplug the ethernet cable, the interrupts stop coming, so nothing strange with that part.