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DS125BR820: Will DS125BR820 change RXDET mode if to change its setting after RXDET already complete device detected?

Tiger Yeh
Expert 5475 points
Part Number: DS125BR820

Hi~

So far, my customer is using DS125BR820 for both of PCIE and SATA application.

One question for RXDET is

1. The system is complete booted and DS125BR820 does finish RXDET termination detection.

2. The RXDET is also tied to BMC's GPIO, however, the BMC will be re-initialized after booted.

Then RXDET pin setting will be changed. (PWDN is not re-toggled).

In this condition, will RXDET setting be changed?

In other words, RXDET will only be set from PDWN toggle or it is dynamic?

  • 0
    TI__Mastermind 43795 points

    Hi Tiger,

    The RXDET logic will not reset unless PWDN is toggled so the results of a previous RXDET operation could remain intact.  The exact outcome depends on the previous and next state of the RXDET pin.

    Since the DS125BR820 does finish RXDET detection, the termination is already set to "active" and the common mode is connected to AC GND.

    When the RXDET pin is changed, either the termination will stay "active" or it will be forced to "Hi-Z"

    The termination will stay "active" if RXDET input = R (20K to GND), Float, or Vin.

    The termination will switch to "Hi-Z" if RXDET input = 0 (1K to GND)

    Regards,

    Lee