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TUSB544: unused pins when I2C control

K.Yaita
Guru 29720 points
Part Number: TUSB544

Hi Team,

I believe the following pins are unused when I2C control.

DEQx
DIRx
SWAP
CTL1
CFGx

Could you tell me how to do with these unused pins?

Best Regards,
Yaita / Japan disty

  • 0
    TI__Expert 7395 points
    As mentioned in the TUSB544 datasheet, at section 8.2.2:

    "In I2C mode, the equalization settings for each receiver can be independently controlled through I2C registers. For this reason, all of the equalization pins (UEQ[1:0] and DEQ[1:0]) can be left unconnected. If these pins are left unconnected, the TUSB544 7-bit I2C slave address will be 0x12 because both UEQ1/A1 and UEQ0/A0 will be at pin level "F". If a different I2C slave address is desired, UEQ1/A1 and UEQ0/A0 pins should be set to a level which produces the desired I2C slave address."

    Same applies to the other terminals (can be left floating)

    Regards,
    Jorge
  • 0 in reply to Jorge Llamas (SWAT)
    Guru 29720 points

    Hi Jorge-san,

    Thank you for your support.

    I would like to confirm just in case.
    Figure 35 shows dot-line at CFGx / DEQx / DIRx / CTL1, so I believe these pins can be left unconnected when I2C control.

    On the other hand, there is solid line at SWAP pin.
    Should my customer connect SWAP pin to voltage divider when I2C control?

    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    TI__Mastermind 36085 points
    Hello yaita-san,

    The solid line is because this pin is more intended for active cable applications, where the chip could be on either side of the connection (next to DFP or UFP), For non active cable applications this pin will be stable (usually normal operation), so the recommendation is to have the default value populated (pull-down resistor).

    Regards,
    Diego.
  • 0 in reply to Diego Cortes
    Guru 29720 points

    Hi Diego-san,

    Thank you for your support.
    I understood SWAP pin shouldn't be left unconnected.

    Best Regards,
    Yaita