AnsweredAssumed Answered

ADAU1701 - cannot get I2S in to I2S out

Question asked by bobw on Jun 2, 2015
Latest reply on Jun 8, 2015 by bobw

The design uses an I2S input stream that provides:

1) 12.288MHz MCLK feeding the MCLKI pin (as well as MCLKI on an external DAC)

2) 3.07MHz BCLK feeding the INPUT_BCLK pin

3) 48KHz WCLK feeding the INPUT_LRCLK pin

4) SDATA feeding the SDATA_IN1 pin (SigmaStudio Inputs 4,5 of the input block)


For the MPIO pins, the I2S ports are setup as above. Proper clock phases have been verified on the logic analyzer

MCLK=256fs, BCLK=64clks/wclk, Input format is I2S


I've connected the input block input 4 to DAC0 and input 5 to DAC1 (due to INPUT_SDATA0 and INPUT_SDATA1 lines swapped, as my serial data is on SDATA1)


The DACS are used to monitor the converted input I2S. However, no signal appears on the outputs...

DACS are not powered down, nor muted.


For the output side:

1) The DAC MCLK is connected to MCLKI (above, sourced by the input I2S MCLK)

2) OUTPUT_BCLK is connected to the DAC BCLK

3) OUTPUT_LRCLK is connected to the DAC WCLK

4) OUTPUT_SDATA0 is connected to the DAC SDI


RAM MODULO is set to non-zero otherwise the output I2S does not work?!

I was not aware that this was used in the 1701. Can someone please clarify this.

The I2S output side is setup as a master.


I've verified the output DAC by instantiating a sine oscillator and sending it out the I2S to the DAC. Signal at the DAC is good!

It is also routed to the 1701 DACS and signal is good there as well.


My problem - I2S is not working. Any ideas?