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TAS2770EVM: Trouble reading data over USB

Andrew Taylor76
Prodigy 30 points
Part Number: TAS2770EVM
Other Parts Discussed in Thread: TAS2770

I am initially trying to send a signal to the amplifier and read out the voltage and signals using Audacity.
I have tried several different combinations of USB audio settings as well as TDM settings. With some combinations of settings I can sucessfully read the current signal. However, I have never been able to read the votlage or any of the other signals such as Die Temperature, Gain, etc. They usually read out completely zero (not even any normal white noise) or, depending on the settings, "noise" that is very high in amplitude (sometimes appering similar to square wave). This high amplifitude "noise", if present, is even present when no stimulus is played.
How can I sucessfually read out both the current and voltage signals over USB audio?
Thank you.

  • 0
    TI__Guru** 108765 points
    Hi Andrew,

    Welcome to e2e.
    You should take into account several things:
    - Vsense and Isense data uses two slots
    - Vsense and Isense must be both enabled to obtain other data like Temp and VBAT
    - You might be sending different data in the same slot of the same channel

    If you have a digital analyzer to visualize TDM data it could help, from my experience I've seen that Audacity is recording only slot 0 data.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    Prodigy 30 points
    Hi Ivan,

    Thanks for your response.

    Yes, I can see in the PurePath Console that the Isense and Vsense are using two slots each. How is this working exactly for a mono amp? For example, if Isense is set to slots 0, 1, is the current always sent on slot 0 and no signal sent on slot 1? Is slot 1 reserved for the current signal of the second amplifier if two are configured in stereo?

    Thank for you the other hints. However, I believe I always have Vsense and Isense enabled, and I think the PurePath Console prevents me from assigning two different data on the same TDM slot.

    Do you recommend a different program that correctly reads all the slots over USB audio?

    If connecting directly to the I2S pins, can the TAS2770EVM be configured for I2S or for 4 or 8 channel TDM?

    Best Regards,
    Andrew
  • 0 in reply to Andrew Taylor76
    TI__Guru** 108765 points
    Andrew,

    The slots for each data is configured by registers TDM_CFG5 to TDM_CFG10. You can enable each data and select a time slot.
    In PPC3, you can enable the "advanced" settings, that allow you to do some major changes to the configuration.
    By default on the EVM it is configured for 8 channel TDM, as you can daisy-chain up to 8 devices.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Andrew Taylor76
    TI__Guru** 108765 points

    Andrew,

    In order to have a better picture of the feedback data (IVsense, etc) I would recommend the following:
    - In PPC3 -> TAS2770 app -> Device control tab: Enable I-sense and Vsense
    - Go to TDM Transmitter -> Configure Slots: Add I-sense in slots 0,1 and V-sense in slots 4,5
    - Power Up
    - Playback audio or tone and record (you can use Audacity)
    - Data from slots 0,1 will be shown in one channel and data from slots 4,5 will be in the other channel.

    The data is sent back in 8 different slots, PC interprets this data as I2S so slots 0 to 3 will be in the left channel and 4 to 7 in the right channel.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    Prodigy 30 points
    Thank you. I can now successfully read both the current and voltage signals using Audacity.