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OMAP-L138: Question about SATA pin configuration

Masato Miyashiro
Expert 1500 points
Part Number: OMAP-L138

Hi,

My customer have created board using OMAP-L138.

However, even though they do not use SATA, they have configured SATA_VDDR pin to supply 1.8V.
If we do not use SATA, it is written in the datasheet that the SATA_VDDR pin should be No Connect.
My customer make SATA pins as configured on the data sheet other than the SATA_VDDR pin .

Is there any problem with this configuration?
Should they change to No Connect?

I would be grateful if you could reply.

Best Regards,
Miyashiro

  • 0
    TI__Guru**** 161600 points
    Hi Miyashiro,

    They should comply with Table 3-33. Unused SATA Signal Configuration from OMAP-L138 data manual. So if they don't use sata, they should leave
    sata_vddr unconnected.

    They should also comply with the rest of the recommendations in Table 3-33.

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    Expert 1500 points
    Hi Yordan,

    Thank you for your reply.
    I replied your answer to my customer.
    However, because my customer has created the board, they can not change anything from 1.8V to the SATA_VDDR pin.
    Therefore, they want to know what effects will be exerted if 1.8V is supplied to the SATA_VDDR pin even though they do not use SATA.

    My customer's idea is that it only supplies power to SATA so that the device will not break.

    If absolutely 1.8V should not be supplied to SATA_VDDR, is there any good workaround?

    I am pleased if you can comment on it.

    Best Regards,
    Miyashiro
  • 0 in reply to Masato Miyashiro
    TI__Guru**** 161600 points
    Hi Miyashiro,

    Apologies for the delayed reply.

    If absolutely 1.8V should not be supplied to SATA_VDDR, is there any good workaround?


    If you DON'T use the other sata pins (even the ones that can be muxed as GPIO or something else) you should be fine. There should be no issues.

    In my experience with other TI devices, if you don't follow the dm recommendations, you MAY have instabilities (even though it is rare) on the other pins (in your case other SATA pins).

    Another thing I see is, that if you power the SATA_VDDR with 1,8V as described in the DM and use the other sata pins as GPIO for example, you can only interface them with 1,8V signals, because the i/o buffers will be powered with 1.8V. Anything more than that can damage the IO cells.

    A workaround would be to correct their design following the DM recommendations & the reference TI designs.

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    Expert 1500 points
    Hi Yordan,

    I apologize for the late thank you.

    I understood your comment.
    And thanks to you I was able to reply to my customer.
    Thank you again.

    Best Regards,
    Miyashiro