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DS80PCI402: RXDET & Table 4

Go Bravos
Expert 6090 points
Part Number: DS80PCI402

Hi,

I need to determine how to operate the repeater with a downstream device that does not support RXDET. In my setup, DS80PCI402 is operating as a SMBus slave device. PRSNT pin “active”, RXDET = “1”?

Table 4 of datasheet does not match text in datasheet. PRSNT pin is “active” when a downstream device is installed. I have the RXDET external pin with 1K pullup.

Table 4 from datasheet has a RXDET column and a Bits [3:2] column. I presume that this is referring to reg addr 02, but Table 9 calls these bits RESERVED. Is the RSDET column ORed with the BIT 3:2 column? Does one column override the other?

Please advise -- thank you.

  • 0
    TI__Mastermind 43795 points

    Hi

    With PRSNT = Active Low and RXDET = 1 the device will enable receiver terminations.  Pin control takes priority over register control for the RXDET function.

    If the downstream device I would leave RXDET = 1.  In this mode it does not support RXDET either but the terminations will be active and the upstream device will be able to detect them.

    The register bits refer to the channel controls for RXDET.  For channel 0 it is register 0x0E[3:2].  In order for these bits to take priority you must also write the override bit in register 0x08[3].

    Regards,

    Lee