AnsweredAssumed Answered

MCF52259 FEC transmit data problem

Question asked by Marco Maioli on May 23, 2014
Latest reply on May 30, 2014 by TomE



I'm using our proprietary board (like demo board).


The FEC module always works well but only if the message size up to 800 byte.

When the size is >950 byte the FEC simply doesn't send out the packet.

I can check it via wireshark: when I try to send a packet of this size or larger, the transmission stops.

So TCP stack perform some retry, but nothing go out. No interrupt errors detected.


Internal bus clock: 80MHz

MAX_FL: 1518

MII_MODE: enabled

1664 byte are allocated for each DB buffer, aligned 16.


FEC registers are so set:


MCF_FEC_EIMR       0xfaf80000

MCF_FEC_RDAR      0x1000000

MCF_FEC_TDAR      0x0

MCF_FEC_ECR        0xf0000002

MCF_FEC_MMFR     0x0

MCF_FEC_MSCR     0x22

MCF_FEC_MIBC       0x40000000

MCF_FEC_RCR        0x6800004

MCF_FEC_TCR         0x4

MCF_FEC_OPD        0x16200

MCF_FEC_IAUR       0x0

MCF_FEC_IALR        0x0

MCF_FEC_GAUR      0xffffffff

MCF_FEC_GALR      0xffffffff

MCF_FEC_TFWR      0x0


I do not understand why the transmission stops, any ideas?

Thanks for any suggestions.