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# How to set up the ADAU1962A FS to 48 kHz?

Category: Hardware

As is shown in the ADAU1962A manual that we can  set the FS by changing the DAC CONTROL 0 REGISTER [2:1] to 00、01、10 or 11 , but the sample rate we choose isn't  a specific value(e.g. 00 to 32 kHz/44.1 kHz/48 kHz) ,  so how to set the FS to a specific value(e.g. 48 kHz).

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[edited by: GenevaCooper at 10:51 AM (GMT -4) on 7 Jul 2022]
• Hello FIVE,

There is a valid range of MCLK input that the PLL can lock to. There is a divider with four settings to give us four ranges of sample rate values based on the MCLK rate.

Setting 00 is a divider of 256,

Setting 01 is a divider of 128

Setting 10 is a divider of 64

Setting 11 is a divider of 64 but with a low latency filter.

So if you use a 12.288MHz MCLK you get three different sample rates for the three divider settings. ( I will not include the low latency)

So 12.288MHz / 256 = 48kHz,

/128 = 96kHz

/64 = 192kHz

So with this master clock input frequency of 12.288MHz and those three register settings you will get those three sample rates.

If you want 44.1kHZ then work out the math the other way.

44,100 * 256 = 11,289,600 Hz. So send this frequency into the MCLK pin, set the divider to 00 and you will get 44.1kHz

Likewise, 32kHz * 256 = 8,192,000Hz for the master clock.

So you select the range with the register setting and you determine the actual frequency with the clock you send to the part.

Dave T