ADAU1452 TDM8 input, 20kHz signal play, there is pop noise on speaker and periodly.

Hello support team,

1. my system diagram is below.

2. my project is below

but project can not upload sucess. so list below

Input1 is I2S input, DSP is master

Input2 is TDM8 input, DSP is slave

3. The output wave have captured, this clip make pop, and periodly.

4. I have directly connect A2B to TDA7803a, no pop noise.

5. TDM8 input format is below.

Please help to check where is the problem, it is urgent for me.

Thanks.

Fish.

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    •  Analog Employees 
    on Dec 4, 2020 2:25 PM 4 months ago

    Fish,

    I believe the issue is that you are seeing the Fs mismatch between the local clock and the A2B bus clock. If the DSP is slave to A2B, then all of the peripherals must be slave to the A2B clock, as well, or come in through ASRCs. The DSP cannot be a clock master to peripherals if the core is a clock slave. If this is your own board, the hardware rework likely would be difficult to fix. I would suggest that you keep the I2S input as a clock master, but pass it through an ASRC to bring it to the core rate. Also, you should select the START_PULSE, which is the effective frame sync for the core, to be the serial port rate of the A2B input. This is controlled on the CORE_CONTROL tab in the upper left.

    Ken

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