SGTL5000 audio capture problem

[icayon]

Hi,

We are working with a imx6q custom board with sgtl5000 audio codec. We are using last yocto version, the image is working ok, the audio driver is loaded and we can play wav files using "aplay".

The problem is when we capture audio from Mic or Line. The signal is clipped and the audio captured is horrible. We test a lot of combinations but we couldn't reach any solution.

We see that when we are capturing audio from microphone and increase the capture volume, when the capture level reachs 33 the audio is muted and stops capturing. The same problem happends with the "Mic" input gain, if this value

is greater than 0 the capture is stopped.

The signal is only clipped in the positive part, so we tried to change the ground reference register to see if this was the problem, but it seems not. I attach a picture playing 1Khz tone.

Please, do you have any idea?

Thanks a lot!

Regards,

@

[igorpadykov]

Hi Ivan

sgtl5000 audio codec is not supported in i.MX6 NXP BSPs, but some third party support it:

Microphone input on the SABRE Lite and Nitrogen6x - Boundary Devices 

example of dts file : linux-imx6/arch/arm/boot/dts/imx6qdl-sabrelite.dtsi

linux-imx6/imx6qdl-sabrelite.dtsi at boundary-imx_4.9.x_2.0.0_ga · boundarydevices/linux-imx6 · GitH... 

Best regards
igor
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[icayon]

Hi Igor,

Thank you very much for your help ! :smileyhappy:

I took a look again how my dtsi file is, and the only changes are

related with

the mux ports the board is using, but I assume that this configuration

is correct

because the chip can be accessed, I can playback and capture, and change

configuration with alsamixer.

Yesterday we used an old imx53 devel board which mounts a sgtl5000 and

it captures

perfect. I dumped the register configuration and I didn't see any

relevant difference between

both boards.

I reviewed sgtl5000 datasheet and play with the registers related with

gound, reference and

so on, but the input signal was clipped too.

Any idea? Thank you very much

Best Regards

El 08/01/2019 a las 1:58, igorpadykov escribió:

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Re: SGTL5000 audio capture problem

reply from igorpadykov

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[igorpadykov]

Hi Ivan

one can try to dump registers on good and not working
boards and compare them.

Best regards
igor

[icayon]

Hi Igor,

Thats exactly what I did, dumping the registers in working and not working boards, but I didn't find any relevant difference. Taking a look at the clipped signal it seems it could be a reference or supply problem, but at hardware level

we don't see any problem.

Best regards,

[igorpadykov]

Hi Ivan

if this is just on one board it may be soldering issue, one can replace codec.

Best regards
igor