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DP83630: USE PHY as sniffer

Part Number: DP83630


I plan on using the DP83630 PHY with  the TMS5704357BZWTQQ1 hercules uP (similiar to the setup on the  HERC launchpad).

Can I use the PHY as just a "sniffer" on an ethernet switch?

that is,  our customer does not want us "transmitting" on the ethernet , but we would like to be able to "sniff" certain messages on the network  (i.e. for insttance, to strip off the gps location of the vehicle, and other vehicle info).

this is a autnomouse vehicle app.

I see the TX_EN pin  which I thought might be able to be controlled...but not sure.

again..not expert on the part...but figured I'd ask.....

than you for any response.

  • Hello John Young, 

    Thanks for the query and detailed analysis. Based on the analysis this should work. The DP83630 includes 1588 hardware stamping. If you do not need that feature, there are alternatives you could consider.



  • So, you believe that by  holding the TX_EN low, the device will not transmit...correct?

    does this MII isolate mode accomplish the same thing?

    (from SNLS335B –OCTOBER 2010–REVISED APRIL 2013, page 41)

    While in Isolate Mode, the PMD output pair will not transmit packet data but will continue to source
    100BASE-TX scrambled idles or 10BASE-T normal link pulses

    thank you. just want to be sure about being able to "prevent transmissions" on the fly./

  • Hello John Young, 

    Please see below 

    When in the MII Isolate Mode, the DP83630 does not respond to packet data present at TXD[3:0] and TX_EN inputs and presents a high impedance on the TX_CLK, RX_CLK, RX_DV, RX_ER, RXD[3:0], COL, and CRS/CRS_DV outputs. When in Isolate Mode, the DP83630 will continue to respond to all serial management transactions over the MII.

    I am not sure if you could use this configuration.



  • Sreenivasa,

    is there a tech rep that would have more info on the way I would like to use the DP83630?  that is, I would have it plugged into my ethernet switch, which has multiple drops to a private network (i.e. several Hercules microprocessors distributed across the network...)...and for this particular node with the DP83630 (attached to the Hercules), aI want to be able to "listen only" ...i.e. sniff the ethernet traffic and look only for particular messges ...(i suppose it would be like an ethernet HUB...?

    thank you'

  • Hello Hello John Young, 

    Thank you for the mail and inputs.

    This is not a typical use case for the Ethernet PHY and would probably need discussion as you mentioned.

    Could you please reach out to your nearest TI sales/FAE tor more support and closer interaction.