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DM648 3-port switch address filtering not working for me

Sergey Chub
Intellectual 400 points

Hello.


I am currently cracking on a DM648 with the goal of establishing a secure ethernet point-to-point connection with the PC to provide a fast data transmission channel for downloading image frames right in the middle of the DSP processing them (at various stages). I'm trying to make the 3psw work properly, and I kind of fail.


I am bypassing the NDK, building it all from scratch. Everything up until now was more or less straightforward, but now I'm stuck figuring out the right way to tackle the ALE. My problem is, the DSP seems to accept all the packets being sent to it (mostly broadcast) without filtering anything. I need it to accept only a handful. However, as I try to configure the table, I always end up with the packets I need being discarded and the broadcast ones passing through. Can you please give me some ideas about the correct sequence of steps that get the ALE working the way it is supposed to? If there's an appnote or something similar, I would appreciate it tremendously if you could provide a link.

Thank you in advance

  • 0
    TI__Mastermind 35645 points

    Hi Sergey,

    Thanks for your post.

    I do not work much with the DM648 Ethernet subsystem, but I think the CFI and VLAN terms refer to Virtual Local Area Network (VLAN), and Canonical Format Indicator (CFI) and are part of 802.1Q. There are a number of threshold values mentioned in the Ethernet subsystem guide below, I believe the flow threshold registers just setup a trigger to implement flow control based on FIFO status:

    http://www.ti.com/lit/ug/spruf57b/spruf57b.pdf

    When the ALE receives a packet that contains errors (due to a set header error bit) or a MAC control frame and does not receive an abort, the packet will be forwarded only to the host port (port 2). No ALE learning occurs on packets with errors or MAC control frames. To know more details on ALE and its address table, please refer section 3.5 from the above 3PSW ethernet subsystem guide.

    Please check the wiki link below:

    http://processors.wiki.ti.com/index.php/Using_two_DM648_EMACs_separately

    You can also take a look at the DM648 throughput app note for the Ethernet benchmarks:

    http://focus.ti.com/lit/an/spraaz9/spraaz9.pdf

    Thanks & regards,

    Sivaraj K

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