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AM3517 EMAC Usage Problem

phoenixtju
Expert 1600 points

Other Parts Discussed in Thread: AM3517

Hi，All

We want to use AM3517 EMAC + Eth Switch Device Chip to support two  Ethernet Port.

How should we choose Eth Switch Device chip， for example:

should I choose KSZ8893 or KSZ8863RLL Chip ?

IF KSZ8893, AM3517 + KSZ8893 works like:

IF KSZ8863RLL, AM3517+KSZ8863RLL works like:

 

can AM3517 support both working mode or just one of the two working mode?

 

Thanks a lot!

 

  • 0
    TI__Guru* 92961 points

    You could potential do either one.

    The AM3517 EMAC is intended to connect to a Ethernet PHY using RMII (see figure 22-2 of the TRM).  If the KSZ8893 supports this, then that could be used. 

    Since the KSZ8863RLL has an EMAC in it, you would probably want to connect this to a general purpose interface like the GPMC of the AM3517. 

    Regards,

    James

  • 0 in reply to JJD
    Expert 1600 points

    Hi, James

    Thanks a lot.

    As you know KSZ8863RLL has an EMAC in it, but we want to connect AM3517 EMAC to KSZ8863RLL EMAC together to support two ethernet ports.

    Can AM3517 EMAC be used this way? and Can it be used to support more ethernet ports?

     

    Thanks

     

  • 0 in reply to phoenixtju
    TI__Expert 8250 points

    Hi,

    Using KSZ8893 makes sense if you require 2 ethernet ports. The picture shown describes correctly how it should be connected(assuming the part supports RMII interface). With this configuration, the EMAC on AM3517 shall operate in NO_PHY mode - similar approach has been verified  on other TI SoCs that have the same EMAC module.  The driver needs to be modified to if you want to segregate the traffic from/to the 2 ethernet ports.

     

    If you want to use KSZ8863RLL, you will interface the "KSZ8863RLL" through GPMC interface and unless the "KSZ8863RLL" part supports a large FIFO size and ability to DMA over GPMC the performance you can achieve in this mode will be limited. 

     

    Regards

    Sriram

  • 0 in reply to Srirama Govindarajan
    Expert 1600 points

    Hi, Srirama

    Thanks for your reply.

    1. When Using KSZ8893, how to configure EMAC on AM3517 to work in NO_PHY Mode? Would you pls give me some advice on how to modify driver to segregate the two ethernet port ?

    2. You mean if I use KSZ863RLL, the KSZ8863RLL can only interface through GPMC interface to AM3517? It can not be interfaced to EMAC interface of AM3517? Is that right?

    Thanks