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ADAU1701: working at 96Khz

Question asked by andrea.labhf on Jul 13, 2010
Latest reply on Sep 13, 2011 by bcoquille

Hi at all.

I need a clarification about 96Khz mode using ADAU1701.

My system is composed by one adau1701 and one AK4620 codec, plugged toghether via I2S (ADAU is MASTER)

The adau1701 is configured for selfbooting via  I2C.

The desired sample rate is 96Khz

 

1. Can I use a standard EEPROM for SB or I must use only 1Mhz I2C eprom? (I2C speed in ADAU is determined by FS, and with a FS of 96Khz I2C clock is 696Khz)

 

2. Can I use a 24.576Mhz XTAL ? (this frequency is required by codec for properly work at 96Khz). In the adau Datasheet I can't find any specification regarding maximun XTAL frequency.

 

3. If PLL_MODE pins are configured for working at 48Khz (calculating FS by a known MCLKI clock) but in SigmaStudio project I select an FS of 96Khz; How does it appens? The ADAU is working at 96Khz or 48Khz? I've tred and all works good but I can't verify the effective internal FS frequency.

 

4.  In sigmastudio there is a message that advise if the project is too big and DSP run out of Mips.

I've verified that this advise ignore the selected Sampling Frequency and ever consider the maximum instruction number aviable if you run at 48Khz.

If you run a project at 96khz, and the project exceed the mips aviable, you can't see any error but the DSP doesn't work.

Is there a way to see the Instruction cycle used in the "compiler outputs" like you can do with the ADAU1446?

 

ps: I doesn't use internal ADC or DAC, so I only consider the computational sampling frequency.

 

Thanks in advance

 

Andrea

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