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About register configuration sequence on ADAU1977(ADC)

Question asked by IRON on Dec 16, 2015
Latest reply on Jan 14, 2016 by DaveThib

Hello all,

I am now trying to accomplish a talk through program using ADAU1977(ADC), ADSP21489(DSP), and AD1934(DAC).

I have a question about register configuration of the ADC.

 

A little ago, I have gotten an answer from ADI that After locking PLL, I can freely configure any registers in any order.( https://ez.analog.com/thread/79520?sr=stream)

If I configure the ADC’s registers in different order just like below, the DAC output different waveform. So, I guess there is a certain order to configure them.

 

1.Disabling VREF and LDO then Master Power up ⇒ desirable wave form is outputted.

2.Master Power up then disabling VREF and LDO ⇒ nothing is outputted.

 

In terms of register configuration, I do the same on both cases.

However, the output waveforms become different if I change the configuration order.

Does this mean there is a certain sequence to take care of?

 

Best Regards,

Yuta Mihara

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