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Digital loop voice. Errata in TPS65950 TRM

Subhasish Ghosh
Prodigy 80 points

Other Parts Discussed in Thread: TPS65950, OMAP3530

Hi,

On Fig 14.7(Voice/Audio Option 2 (OPT_MODE = 0) Block Diagram) of the TPS65950 TRM, I found the Voice Digital Loop (Marked with the Light Blue line), but could not find any register in the TPS to configure it.

It looks like its mainly used for Silicon level testing.

Does any one have any documentation regarding this.

What I am basically trying to do is, Loop the I2S (RX) interface with the PCM (TX). For the purpose I require the Digital voice loop to complete the path. Has anyone tried this before ??

  • 0
    TI__Genius 15100 points

    Hi Subhasish,

    This is a test only loop and not recommended for application purposes. Sorry for the confusion by having it on the figure.

     

    Regards,

    Gandhar.

     

  • 0 in reply to Gandhar Dighe
    Prodigy 80 points

    HI Gandhar,

    I am trying to loop between the I2S and PCM interface of the TPS. This is only for automated testing of our product and not for any applications.

    Basically, what I intend to achieve is a loop between McBsp2 and McBsp3 (on OMAP3530) through the TPS  and hence validate these interfaces.

    This requires the usage of the voice digital loop to complete the path.

    I am not sure if this is even possible. [:(]

    Is there any registers settings to enable this voice digital loop.

    Thanks,

    Subhasish

     

  • 0 in reply to Subhasish Ghosh
    TI__Genius 15100 points

    Hi Subhasish,

    You can try the path I2S -> RX filter -> TX filter -> PCM.

    However, I am afraid the PCM -> I2S will not be implementable.

     

    Regards,

    Gandhar.

     

  • 0 in reply to Gandhar Dighe
    Prodigy 80 points

    Hi Gandhar,

    Is there any updates on this diagram. There seems to be more issues with it.

    1. If I try to find a path b/w BT and HS, there seems to be none!.

    This is the only way to do this:

    BTDIN - > BTTXPGA -> SUM ->  PCMBTMUX -> VRXPGA -> SUM -> VDLFilter -> Blue-LIne.

    The problem is, this blue line in not active (Voice digital loop), or is this a misrepresentation.

    2. Is the line VDXS again related to Voice digital loop, in that case how do I implement the loop that you suggested.

     

    Is this way of figuring out what registers to configure the best way, or do you have any other suggestions.

  • 0 in reply to Subhasish Ghosh
    TI__Genius 15100 points

    Hi,

    1. If you are searching for Bluetooth to Headset then you almost got there - SUM -> VDLFilter -> Modulator -> DAC -> Analog output to Headset

    2. The VDXS is the uplink which is part of normal PCM path (nothing to do with digital loop). You had asked a path from I2S to PCM and that is what I told you. The path you have marked in the attachment is the correct path. You will need to use DIGMIXING.VTX_MIXING. However, keep in mind that the data looped back may not be exact (bit for bit) as the digital filter would affect the data. we cannot bypass the filters so we can see the same data.

    It is best to refer to the figure for identifying the register. That way you are sure which path and what settings need to be configured. There are too many options and hence the configuration can be a bit complex.

     

    Regards,

    Gandhar.