Because of the holidays, TI E2E™ design support forum responses will be delayed from Dec. 25 through Jan. 2. Thank you for your patience.

  • State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 31 subscribers
  • Views 1295 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TUSB9261 SATA/USB3 Bridge, Polarity Swap

riccardo palchetti
Prodigy 40 points
Other Parts Discussed in Thread: TUSB9261

Hello


I'm about to design the TUSB9261 into a new product. To tie everything together I'll have to route the SATA TX and RX tracks from this IC through my board and with high-speed lines crossing each other.

As far as I can see, TI's documentation for this chip permits the swap for USB SuperSpeed lines ( Page 20 of datasheet "It is permissible to swap the plus and minus on either or both of the SuperSpeed differential pairs" ).

My question is: Is possible to apply the same way of thinking for the SATA traces and then swap SATA_TX (plus and minus) and SATA_RX  (plus and minus) lines? (Pag 20 of datasheet) "It is permissible to swap the plus and minus on the SATA differential pair". Is the swap applicable only to TX lines or even to the to the RX traces?

Thanks in advance,

Nicola

  • 0
    TI__Guru* 76130 points
    Hello,
    Yes, both USB3.0 and SATA allow for polarity swap in the TX lines only.
    Since the TX of the host will go to the RX of the device, and the device is also allowed to swap its TX lines, then that is why the Spec only talks about swapping the TX lines.

    The TUSB9261 use different firmware when the TX polarity is swapped, if you download the firmware package from ti.com (link below) and then you run the installer, the wrapper will install both firmware called "...polarity swap.." and "..no swap..."
    Then you can use the flash burner utility to program the attached SPI memory with the required firmware, user guide is available at ti.com as well.

    Regards
    www.ti.com/.../toolssoftware
  • 0 in reply to Elias Villegas M.
    Prodigy 40 points

    Hi,

    First of all thanks for your response. So from your message above I've understood that it's possible to swap only TX linex both for SATA and USB Superspeed traces. After I downloaded the firmware from the link that you inserted. Inside the folder "Alternate SATA Polarity FW" there are different binary files and it seems that it's possible to swap also RX lines: "TUSB926x_FW_v1.05_SATA_POLARITY_SWAP_BOTH.bin". This is confirmed also by readme.txt file.

    So is my opinion correct?

  • 0 in reply to riccardo palchetti
    TI__Guru* 76130 points
    Yes, that is correct.
    Regards