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AD1938 BCLK trouble

Question asked by mbente on Oct 28, 2011
Latest reply on Nov 18, 2011 by mbente

Hello to all,

 

i designed a product with the adau1442 and multiply AD1938 Audio Codecs. In first i transfert all the audio datastream in stereo mode. Now i want to minimise the cable and change the system to work with TDM8 mode. So this is still working at the moment.

 

I have trouble with generating the BCLK of the ADC internaly. In case of the DAC it works fine.

 

I'm generating the MCLK with the internal PLL from the LRCLK. So the only Audio-lines i want to connect to the AD1938 should be:

- ADATA

- ALRCLK

- DATA

- DLRCLK

is it possible?

 

If i switch the ABCLK into the internal mode the ADC Datastream fail. My configuration works only if i connect ABCLK to the AD1938 and switch to external BCLK mode.

 

The DAC performs his operation in both modes.

 

Do you have an idea how i could change my configuration to minmise EMI and cable connections?

My configuration is updated at the moment in SigmaStudio 3.1 with USBi interface connected to the ADAU1442(i2c), EEPROM(i2c) and AD1938(SPI)

Thank you very much!

 

M.Bente

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