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Original question:

TAS5805M: I2S stable time at startup procedures for TAS5805M

TAS5805M: TAS5805M - Startup Procedure

C%20K%20Ong
Expert 1240 points
Part Number: TAS5805M
Other Parts Discussed in Thread: TAS5805

Hi,

The TAS5805M datasheet indicate startup procedure requires I2S to be stable before sending I2C commands to TAS5805M.

Is 'stable' means the clock is not halt, and the ratio of SCLK/Fs is 16, 32 or 64?

If I have continuous close with SCLK=512KHz and Fs=8KHz, ratio = 512/8 = 64, consider a stable I2S clock? 

  • 0
    TI__Genius 9995 points

    Hello customer,

    Correct. As to ratio of SCLK/Fs, it depends on your I2S source. Eg. Fs=48KHz and SCLK is 3.072MHz, which means both left channel and right channel has 32bit data width.

    I do not think TAS5805 supports 8K Fs. When TAS5805 judge whether clock is fault or not, it detects both Fs and the ratio. Please refer to the datasheet about supported Fs (32K, 44.1K, 48K, 88.2K, 96K).

    Thanks!

    ALix Wan.

  • 0 in reply to Alix Wan
    Expert 1240 points

    Dear ALix,

    Looks like TAS5805M support 8KHz.

    We do not need TAS5805M to support Fs=8KHz playback.

    We just want to make sure when SCLK/Fs = 512KHz/8KHz, can we send configuration parameters to TAS5805M via I2C  without issue.

  • 0 in reply to C%20K%20Ong
    TI__Genius 9995 points

    Hello customer,

    Per my check with designers, 8K Fs is not supported in our specification. I will update the datasheet in next version.

    As to your need for 512/8=64, i am afraid that it is possible to report error. Can you share why it is a must to have SCLK=512K and Fs=8KHz, is it for human voice?

    Can you consider to use SRC to up-sampling the Fs to 32 with a factor of 4? It is not hard for MCU/SoC. Thanks!

    Regards,

    Alix Wan.

  • 0 in reply to Alix Wan
    Expert 1240 points

    Dear Alix,

    We are using 44.1KHz in audio playback.

    The 512KHz/8KHz only happened when the USB bridge startup or wakeup from sleep mode. While I2S still in 512KHz/8KHz clock, the USB bridge will be initializing the TAS5805M via I2C. That means, 512KHz/8KHz clocking is only happened during TAS5805M initialization.

    After the initialization, the USB bridge will switch to 2.822MHz/44.1KHz clocking.

    So my question is:

    Will TAS5805M receive the I2C initialization data correctly  at 512KHz/8KHz?

    Best Regards,

    CK

  • 0 in reply to C%20K%20Ong
    TI__Genius 9995 points

    Hi CK,

    If you do not do I2C configuration of DSP (not in book 0 / page 0), it is ok.

    But my concern here is:

    1. During the I2C initialization, I2S clocks are needed to be stable and valid. 512k/8k is not allowed;
    2. After the I2C initialization, you need to do wake up or mute the device, it is ok. But my suggestions here is:
      1. mute:
        1. 44.1KHz is ready:
        1. mute/sleep the device
        2. change the clock to 8k
      2. play:
        1. keep in mute status;
        2. wait for LRCLK to be 44.1k
        3. enter into play

    Regards,

    Alix Wan.

  • 0 in reply to Alix Wan
    Expert 1240 points

    Dear Alix,

    We are currently using 512KHz/8KHz during I2C initialization. So far, we did not encounter any issue.

    We will see whether we have window to change.

    Regards,

    CK