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About PLL Lock condition in LRCLK mode for ADAU1977

Question asked by TomY on May 24, 2016
Latest reply on May 26, 2016 by TomY

Hi, ADI Support Team


I have a question about ADAU1977.


When the CLK_S bit PLL_CONTROL register is set to “1:LRCLK”, which timing does LRCLK signal have to input?

In my system, the PLL_LOCK bit (Bit7) of PLL_CONTROL register indicate “1:PLL Locked” in spite of without LRCLK input.

Is it correct behavior?

I guessed that to become "PLL Locked" LRCLK input is needed.


For your reference, my sequence is as follows.

- Write 0x01 (Power-Up) to M_POWER register

- Write 0x51 (LRCLK mode) to PLL_CONTROL register  *In this timing, there is not LRCLK input.

- Read PLL_CONTROL register as 0xD1 (PLL Locked)


Thanks in advance,