TMDX5535EZDSP: Audio Pre-Processing: Getting noisy sound output

Abhinandan BR

Part Number: TMDX5535EZDSP

Hi,

I have configured Audio Pre-processing project for 2 Mics from CMB. I have used the software patches from C5517_TIDEP-0077_VoiceProcessing_patch2.

I have also kept a continuous watch expression on buf_Outptr,buf_Outptr2 and inFramePtr.

I am getting random values in inFramePtr, and the sound output via audio out headphones is noisy.

I am attaching a file containing the samples from inFramePtr.

Fullscreen 3750.test.txt Download

Kindly help in solving the sound issue.

over 8 years ago

0 Cvetolin Shulev-XID over 8 years ago

TI__Guru 65405 points

I've forwarded this to the c55x SW experts. Their feedback should be posted here.

BR
Tsvetolin Shulev

0 Abhinandan BR over 8 years ago in reply to Cvetolin Shulev-XID

Intellectual 945 points

Kindly provide response, and solution .

0 Lalindra Jayatilleke over 8 years ago in reply to Abhinandan BR

TI__Mastermind 30365 points

Abhinandan,

Its difficult to say why you are having noisy audio output. It could be a number of factors that could be causing this issue:

- Incorrect wiring
- Incorrect DMA config
- Incorrect sampling rates
- Incorrect clock settings

You may want to re-check your system settings since you have modified your code from the original example.

Lali

0 Abhinandan BR over 8 years ago in reply to Lalindra Jayatilleke

Intellectual 945 points

Lali,
I have not modified the code.
The code already has macros to set the number of Mics to use. I have set it to 2. So accordingly all configuration is taken care in the program itself.
I think it has something to do with codec. Since c5517 has 2 codecs connected to i2s0 and i2s2 It might work with one acting as input and another acting as output to headphones.
But c5535 has only 1 codec connected to i2s2 . So doing input processing and sending output to the headphones using same codec i2s2 line might be causing the noise issue due to mixing.

Is my analysis correct?

0 Lalindra Jayatilleke over 8 years ago in reply to Abhinandan BR

TI__Mastermind 30365 points

Abhinandan,

The C5535 ezdsp has one codec connected to I2S2 for the headphones.

The CMB has 2 x PCM1864's to handle the audio from the microphones on the CMB. So, I don't think you are using the same codec to do input and output on the ezdsp. Please also check your wiring to ensure that there aren't any loose connections especially on the edge connector.

Lali

0 Abhinandan BR over 8 years ago in reply to Lalindra Jayatilleke

Intellectual 945 points

Lali,
I checked for any possible loose connection. There isnt any.
Also I did a loopback which disables the bf, drc and other processing. Even with loopback I am getting noise.

In previous reply you mentioned I2S2 is connected to headphone output via codec (codec acts only as output). I agree with that.

I have doubt how I2S2 is used for input and output. In 2 Mic configuration, Mics 1 & 2 output is fed to the DSP via I2S2. And same I2S2 is being used for headphone output via codec. So as a result we are using I2S2 for Input and output. Does this has any effect on noise being generated?

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TMDX5535EZDSP: Audio Pre-Processing: Getting noisy sound output