christian GUIRAUDIE

When I use API for FEC (MCF5485), number of datas in send frame it is necessarily divisible by 4 ?

Discussion created by christian GUIRAUDIE on Dec 31, 2009
Latest reply on Jan 5, 2010 by TomE

I try to write a program for FEC unit of microprocessor MCF5485.

When I send a frame of 64 bytes, everything is well, she is seen by the Wireshark application (for example).

When I send a frame of 65 or 66 or 67 bytes, sent frames have quite a length of 68 bytes and they are not accepted by the application.

In other words, the argument length of the structure MCD_FEC_bufDesc (Multichannel DMA API) can be the other thing than a modulo number 4?

I tried to work without the DMA, directly with the unity(unit) FEC, there no problem, I can send frames of 64, 65, 66, 67 bytes.... n bytes.

They are correctly received and they have correct sizes (64[preamble]+12[macs]+2[type]+n[data]+4[CRC] x 0.1 micro.sec. @10Mb/s).

 

It is possible to send frame containing a number of bytes not modulo 4. For example 69 bytes?

Thank you in advance.

Christian.

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