Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

  • State
  • Locked Locked
  • Replies 7 replies
  • Subscribers 30 subscribers
  • Views 332 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.

LM49450: Disable/Enable the 'Headphone Sense' (HPS) feature

Rajarshi Sarkar
Prodigy 20 points
Part Number: LM49450

LM49450_UI_HPS.tif

How can I disable the HPS feature? What should be the I2C register setting for that?

I see in the 'LM49450 I2C Interface' (snapshot attached) there is a provision to either use the HPS feature or the speaker/headphone mode by default

Thanks..

  • 0
    TI__Guru** 102045 points

    Hi Rajarshi,

    Unfortunately some of these LM devices are very hard to support.
    The best I could find is the following description from years ago:

    "Throught the advanced settings, I was able to find out the register settings under the various conditions Use sense pin, Headphone, and Loudspeaker. Each of them had a different register setting at 0x0Fh (reserved register) which I believe is where the modes are configured."

    It seems there is no access to the GUI or EVM documentation (EVM is no longer available), if you have the GUI on your side please let us know, we may be able to double check this information.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    Hi Ivan,

    I didn't find any Register with 0x0Fh. The mode control register is 0x00h as mentioned in the datasheet (snapshot attached).

    And there is no mention of enable/disable of the HPSense feature in the 0x00h register.

    Also, I don't have the GUI with me. 

    Thanks.

    LM49450_ModeCtlReg.tif

  • 0 in reply to Rajarshi Sarkar
    TI__Guru** 102045 points

    Rajarshi,

    There is no documentation including this register 0x0f, as mentioned the available information is limited and I could not locate any version of the GUI to investigate further.

    Where did you get the first GUI capture?

    Since there is no further information, I can only suggest to try writing different values on register address 0x0f, even if there is no description about it, there may be a couple of bits where you can select either HPSense, HP mode or LS mode.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    Hi Ivan,

    I got the GUI snapshot from this forum itself.

    Since there is no information about the 0x0F register as you mentioned, could you pls let me know which 2 bits I need to change from B7-B0 ? And what should be the other bit configurations by default?

    Thanks.

  • 0 in reply to Rajarshi Sarkar
    TI__Guru** 102045 points

    Rajarshi,

    I have no better guess of the bits associated with this feature. I would try by toggling each bit on the register and check if there is any change on the outputs.
    Regarding default configuration, you may first read the register without writing anything to it yet.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    Sure Ivan. Will try it out.
    Thanks.

  • 0 in reply to Rajarshi Sarkar
    TI__Guru** 102045 points

    Rajarshi,

    Thanks, if you can share your results after test it would really help anyone else working with the same device.
    I apologize for the lack of documentation on some of these LM devices.

    Thanks and Best regards,
    -Ivan Salazar
    Applications Engineer