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ADAU1701 I2S interface problem

Question asked by kruesn on Jun 26, 2013
Latest reply on Aug 9, 2013 by carpens

Hello,

 

I need to connect a bluetooth module as digital audio input to our ADAU1701 using the I2S interface.

The problem is that the BT module doesn't offer an MCLK signal. In the datasheet of the module I found this section however:

 

"In addition to the I2S signals mentioned above, many external codec ICs require a high frequency master clock (MCLK). Typically this clock is a multiple integer of the sampling rate fs, e.g. 128 fs / 192 fs / 256 fs / 384 fs / 512 fs and so forth. Unfortunately, BTM51x cannot provide such MCLK signal. We recommend you select an external codec IC which has the capability of creating the MCLK internally from the bit clock signal (SCK). Such capability is referred to as “PLL” (phase locked loop) or “FLL” (frequency locked loop) functionality of the codec device."

 

I read that the ADAU1701 has PLL but I couldn't get this to work. On this board I found topics saying that the ADAU1701 needs the MCLK anyhow.

What is correct now? Is there any way I can get this configuration to work?

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