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TLK6002 PD_TRXA/TRXB

Longchang Chen
Intellectual 1350 points
Other Parts Discussed in Thread: TLK6002

There are pins PD_TRXA_N and PD_TRXB_N in TLK6002, but customer float these two pins, I think it need Pull –up ,  pls check whether there are internal pull-up? if customer float these two pins, does TLK6002 still works?

many thanks 

  • 0
    TI__Genius 16150 points
    Hi Longchang Chen,

    If the customer floats these pins the device still works due to are internal pull-up.

    Regards!
    Luis Omar Morán Serna
    High Speed Interface Group
    SWAT Team
  • 0 in reply to Luis Omar Moran
    TI__Intellectual 1350 points

    Moran:

    do you tried to read register  in TLK6002 EVK when don't external pull-up these two pins? now customer tried to write and read register of TLK6002, and the timing of MDIO is ok, but TLK6002 doesn't resposne .  So we doubt the problem is at these two pins,  there is not description about internall pull-up  in D/S. pls double check it with EVK.

    many thanks

  • 0 in reply to Longchang Chen
    TI__Genius 16150 points
    Hi Longchang,

    The RTL code of the device indicates that they have neither pull-up nor pull-down resistor and are simply connected to an input buffer. If this is the case, the pins must be externally driven high or low through a Microcontroller, FPGA or Pull-up / Pull-down resistors.

    As well, they need to look at both MDC and MDIO signals and verify that they meet signaling level and timing requirements per our datasheet. One other thing that is not well-documented is that the pre-amble actually needs to be 33 bits long. In applications that hold the MDIO bus idle (high) while MDC continues to run (i.e., between commands) this problem doesn’t show up, but if they are only sending MDC edges when needed for MDIO then it could be an issue. (The fix would just be to modify their MDIO drivers to accommodate the extra pre-amble bit).

    Luis Omar Morán Serna
    High Speed Interface Group
    SWAT Team