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ADAU1966 analog part not working - DAC muted

Question asked by prado on May 10, 2016
Latest reply on Sep 1, 2016 by DaveThib

Hello,

I am working on a project with the ADAU1966A but without out the evaluation board, just the DAC itself. I am writing the registers with the SPI mode and I achieve writing and reading them back right. The thing is that when I input some signal in the DSDATA pins, I see no output, just the common mode voltage. Maybe I am configuring the registers bad or the DAC might be broken (less possibly). I would be really glad if you could have a look at it.

 

I want to use the DLRCLK mode for a Fs of 44.1KHz and 16-bit word. So with the FPGA I send into the DAC a DLRCLK of 44.1KHz and and a DBCLK of 1.4MHz (16bit x 2channel x 44.1KH). I read there are different options for DBCLK per channel, either 16 or 32. So I figured I could use 16 since my data is 16bits and the Left Justified mode so all the data would fit perfectly into the channel (no delay or extra empty bit). Correct me if I am wrong here. I also configured the LF pin as per table with the capacitors and resitors.

 

To write through SPI I do a burst write and then a read of the first  9 registers (I also check reading the others):

00001100     Address of device  and write bit

00000000     Address of first register

01110001     PLL_CLK_CTRL0 - DLRCLK selected and power-up on

00000010     PLL_CLK_CTRL1 - MCLK from PLL

10100000                                      PLL on

00000000

00000000

00000000

01000000     DAC_CTRL0     Left Justified, stereo mode, DAC not muted

00000101     DAC_CTRL1     Normal Operation ,  DBCLK, 16b per channel, DLRCLK/DBCLK Master.

00010010     DAC_CTRL2     Auto-Zero Input Mute Disabled.

 

Still I dont get any output. I guess it could be that I configure the registers in a bad way or my PLL doesnt work properly. I also try the Direct clock mode without PLL and dindt work.

 

I read all the forum about the ADAU1966 and I got some hints but  I hope you can help me further with this.

 

Thank you very much

 

Miguel

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