ADAU1978 configuration

Hello everyone,

I'm a little confused with some of the ADAU1978 settings:

1) what is the MCLK frequency range? The timing specification offers only the table with specific MCLK values that can be used. But how much the MCLK frequency can vary between these values?

2) there's a field in register SAI_CTRL0 named FS which sets sampling rate. But MCLK input and MCS field in PLL_CONTROL register define sampling rate too. What is the difference between them and how do they relate to each other?


Actually, I've been playing with these three parameters (MCLK input frequency, FS field and MCS field) for a while, but failed to find the relation between them. For example, I've set MCLK input to 4,16 MHz and MCS to 128xfs, so I expect the LRCLK will run at 4,16/128 = 32,5KHz rate (in LRCLK/BCLK master mode). But it runs on 10, 20, 40, or 80 KHz depending on FS value (8 to 12, 16 to 24, 32 to 48 and 64 to 96 KHz respectively). I can't figure it out.


Hope, you guys will help me out with this. Thanks in advance.