DA7212 Microphone Input Noise

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aaronbarnes1991
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DA7212 Microphone Input Noise

Hi,

We are designing for an audio applicaiton which requires headphone output and mono microphone input. I have been using the GUI to configure a development board (170-04-A and 169-02-A) and have got the headphone output to work well, but the microphone input has a lot of noise on it and i cannot seem to get rid of it. We require a single ended microphone input on MIC1_N which I think i have configured correctly. I have attached a dump of the registers from the GUI to this post. Do you have any advice on whether our setup is correct or what settings we can change to try and remove the noise? 

Thanks

Aaron

Device: 
ED_Dialog
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Joined: 2017-09-18 11:54
Hello Aaron,

Hello Aaron,

So we had a quick look at the script and your specification. We have a few comments and observations:

1. The script also has the headphone output enabled; do you also have noise on this output?

2. The script has the DAI_FORMAT set to I2S, but your requirements are for DSP Mode.

3. The PLL settings in the script are not quite correct. The hardware uses a 12Mhz crystal however the script has PLL_FBDIV_FRAC_TOP and PLL_FBDIV_FRAC_BOT both set to 0. If you use the PLL calculator in the GUI. For a 12MHz clock and a 32KHz sample rate, PLL_FBDIV_FRAC_TOP & PLL_FBDIV_FRAC_BOT should be set to 24 and 147 respectively.

Does this make sense?

We believe that these register settings are causing the noise issues you have.

We will reach out directly for future support.

Kind regards,
Elliott