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Linux/TUSB544: How to adjust the TX / RX and SBU gain?

He Edwin
Prodigy 30 points
Part Number: TUSB544

Tool/software: Linux

Hi, 

Our project uses the typec for usb3.0 and dp functions, but in the debugging process we found that

some of cable dp transmission failed(ss is ok, dp edid or training failed sometimes).

So,

1.Please help to check method which how to adjust sbu and tx/rx gain?

2.What does VOD Linear Range and DC Gain mean?

We use i2c mode control, 

Thanks.

Edwin.

  • 0
    TI__Mastermind 36085 points

    Hello, 

        We need to estimate the loss of the channel in order to recommend a value for EQ (SBU/AUX have no EQ gain), please share the material and trace length. The DC gain is just a gain in DC domain, meanwhile the VOD linearity can be seen as the maximum linearity of the output, a higher value provides higher range to deliver at the output (which also depends on its input).

    Let's say that you have a 450mVpp signal at the input of the TUSB544 and you have about 7dB EQ gain, then the output signal will be the double (ideally), and the output linearity should be configured to 1000mVpp, in order to handle the output with an extra margin. You can play using the DC gain and VOD linearity in order to compensate possible DC loss in the channel, as well as to maximize the differential output range.

    Regards,

    Diego.

  • 0 in reply to Diego Cortes
    Prodigy 30 points
    okay,
    Ｗhat's means of AUX snoop? if AUX snoop was disabled as well as enable 4lane display whether affect usb2.0 function？

    Thanks.
  • 0 in reply to He Edwin
    Prodigy 30 points
    Whether tusb544 monitors the actual physical layer conditions like display lane, usb ss signal to determine the chip enter to low power mode?
    if not, How to enter to low power mode? and what time to enter sleep mode?

    Thanks.
  • 0 in reply to He Edwin
    TI__Mastermind 36085 points
    Hi,

    The TUSB544 detects the transitions to low power states by detecting the LFPS LGO_Ux commands for USB, and sniffing the AUX channel for changes in the power state and lane count.

    Regards,
    Diego.