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TAS3251: Audio forum

Zou Kenny
Prodigy 30 points
Part Number: TAS3251


Hi
We are using PPC3 to tuning TAS3251, But I can't find  where is the master volume setting, because we need the master volume data to creat the software in MCU for volume control.
Can i use the input mixer data for volume or the input gain data for Volume control in MCU?

  • 0
    TI__Mastermind 19080 points

    Hi,

    No, the thing you need is actually the DSP volume. You can find it in the process flow document.

    Book 8C, Page 1E, Reg 0x44 for Left Channel, Reg 0x48 for Right Channel. Data format is 9.23.

    Regards,

    Sam

  • 0 in reply to Sam(MPAA) Zhang
    Prodigy 30 points

    Hi Sam
     Thanks for you help.
    We found the Volume  information in TAS3251 datasheet, and in the process flow document , please see the attached images. But I can't find the Volume data format in 9.23. Maybe I don't have the right document you mentioned. Could  you tell what is document for software instruction?

    Thanks a lot for your kind help!
    Best regards!
    Kenny

  • 0 in reply to Zou Kenny
    TI__Mastermind 19080 points

    Hi,

    I'm actually referring to the DSP volume... I understand it might be a little bit confusing. Let me make further clarification. The "digital volume" on your last post is DAC gain. DAC gain and analog gain are all at the post stage of the DSP. In the cases where DRC&AGL blocks are used for range mapping and power limitation, users should not change the DSP post stage gain or the DRC&AGL setting will change.

    I've made a screen shot for the DSP volume. It's in the TAS3251 Process flow document(you can find it on product page). The format is 9.23, default value is 0x00800000, indicating 0dB. If you don't have a good tool to make the transition, just use PPC3 I2C monitoring feature, adjust the volume on the top of the window and find out the dB number and the corresponding I2C word.

    Regards,

    Sam

  • 0 in reply to Sam(MPAA) Zhang
    Prodigy 30 points

    Hi Sam
    Thank you very for your information. That is a great help for me.We will use 044/048 for volume control then.
    Can I ask one more help ? Please teach how to caculate the code of volume level, like -0.5dB,1dB,etc. that will be much helpful and easier for me to built it into software. 


    Kind regards!

    Kenny

  • +1 in reply to Zou Kenny
    TI__Mastermind 19080 points

    Hi Kenny,

    The easiest way is to use PPC3 I2C monitoring feature, adjust the volume on the top of the window and find out the dB number and the corresponding I2C word. You can build a look-up table in your header file.

    Regards,

    Sam

  • +1 in reply to Sam(MPAA) Zhang
    Prodigy 30 points

    Hi SAM
    Thank you very much. Follow your instruction,we solved the problem.
    Kind regards!
    Kenny