Quantcast
Channel: Processors
Viewing all articles
Browse latest Browse all 124737

Forum Post: RE: NDK on DM643x Compliance Testing gives FCS error

$
0
0

Hi Prad1,

I'm not the author of that driver but I'll try to help.

[quote user="Prad1"]why is this if condition checking for packets <60 why not 64?[/quote]

I would guess that the driver is checking for a valid length of 60 because it's only counting the frame as:

    [Destination Addr (6 bytes)] [Source Addr (6 bytes)] [Type (2 bytes)] [Data (46 - 1500 bytes)]

(NOT counting the 4 byte frame check)

This will yield a minimum size of 6 + 6 + 2 + 46 = 60 bytes.

The value of 64 is most likely including the frame check:

[Destination Addr (6 bytes)] [Source Addr (6 bytes)] [Type (2 bytes)] [Data (46 - 1500 bytes)] [Frame Check (4bytes)]

Which of course yields a minimum value of 64 bytes.

I think the EMAC h/w can be configured to include the 4 byte frame check.  Can you see what the setting is for the DM643x you are using?

[quote user="Prad1"]We would like to know if it is ok if we change the size from 64 to 60.[/quote]

You are certainly free to try this and rebuild the driver code.  I would be interested to see what happens.  Also, is that if statement ever true for you?

Steve


Viewing all articles
Browse latest Browse all 124737

Trending Articles



<script src="https://jsc.adskeeper.com/r/s/rssing.com.1596347.js" async> </script>