• State TI Thinks Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 2 answers
  • Subscribers 34 subscribers
  • Views 873 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TPS2544: TPS2544 Wake up fail issue

Ann_Lien
Genius 14500 points
Part Number: TPS2544

Hi expert,

My customer is facing an issue which is related to wake up event of TPS2544. Please kindly see below waveform for successfully wake-up(left)/fail wake-up(right) event. We used the same mouse and PC to test. For the failure wake-up event, VBUS drops and D+ drop. And D+/D- will keep both high so that host cannot know that device is plugged in.

Could you kindly help to verify why this event would be like this? Thanks a lot!!

Best regards,

Ann Lien

  • 0
    TI__Mastermind 30000 points
    Hello Ann,

    Thank you for posting your question on E2E. What are the different conditions between the two tests? Was the TPS2544 in different modes between the two or are the two test set ups identical? I'm trying to get an idea as to what could be causing this issue.

    Also, would you be able to send pictures of the schematic for this design? Or at least show the connections for the TPS2544?
  • 0 in reply to Adam Mc Gaffin
    TI__Genius 14500 points

    Hi Adam,

    Thanks for reply!!

    We tested it by same PC and mouse. And the mode is the same(CDP to DCP_auto). This issue is random. Schematic is sent to your mail, thanks!

    Best regards,

    Ann Lien

  • 0 in reply to Ann_Lien
    TI__Mastermind 30000 points

    Ann,

    Since the mouse and PC are the same for both tests, is there a difference in the amount of time that you let the mouse be connected to the system before you enter sleep mode. There is a minimum amount of time for the system to remain in S0 mode before you enter S3 mode, or there could be issues and the device could fail to wake. Is found on page 21 of the TPS2544 datasheet.

    Would you be able to run the same tests that you did before, but have the time connected before going sleep remain constant throughout each test? See if that fixes this issue.

  • 0 in reply to Adam Mc Gaffin
    TI__Genius 14500 points

    Hi Adam,

    Thanks for reply and support as always!!!

    Per checked with customer, there are some points need to verify. We want to know if this "60 seconds limitation" is due to TPS2544.

    There are two cases, one could wake up by mouse successfully and one could not.

    Fail case:

    Sleep(S0 to S3) --> mouse cannot wake up system so we use keyboard(on laptop) to wake up(from S3 to S0)

    Pass case:

    After fail case->Restart laptop(reboot, from S0 to S5 to S0)-->Sleep(S0 to S3)-->mouse can wake up system (from S3 to S0)

    Please be noted that we tested by the same mouse and time device stays in S0 is the same(<60s). We are wondering why we don't have "60 seconds limitation" after system reboot?

    In my opinion, if this limitation is due to TPS2544, it should be the same(cannot wake up system by mouse in two cases) since we will always have this limitation and would not be difference before and after reboot. 

    Best regards,

    Ann Lien 

  • 0 in reply to Ann_Lien
    TI__Genius 14500 points
    Hi Adam,

    Do we have a chance to have your help on this case? Thanks!!

    Best regards,
    Ann Lien
  • 0 in reply to Ann_Lien
    TI__Intellectual 2685 points

    Hi Ann,

    1. TPS2544 supports low speed and full speed devices wake-up from s3 to s0.  

    2. Low speed and full speed devices must stay 60 seconds in CDP mode before switching to DCP_Auto mode.

    3. regarding to fail case, you said both D+ and D- keep high, it should be DCP_Auto mode.

    to solve this issue, please make sure the device will stay at lease 60 seconds in CDP mode (S0) before switching to DCP_Auto mode (S3).