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PCM9211 I2S clock settings

George Nikolaou
Prodigy 220 points
Other Parts Discussed in Thread: PCM9211

Hi All,

I am using the PCM9211 to route an S/PDIF signal (from RXIN2) to the main output port and drive the SCKO, BRK and LRCK clocks.

Everything works correctly and i can observe a signal at DOUT and also measure the following values for the clocks:

SCKO:   11,28MHz     256 x Fs  

BRK:      2,82MHz       64 x Fs

LRCK:    44,1KHz       1 x Fs

The DSP that i am using (and trying to interface withe the PCM9211) is not responding correctly to these settings/clocks, and after i tried with another module that worked correctly, i noticed that for the SCKO clock generates a 512 x Fs instead of a 256 x Fs.

As i want to alter the multiplier for the SCKO, i tried to modify register 0x30h so i can set the SCKO to 512 x Fs, however each time i alter the value from the "Register inspector" it takes the new value, but immediately after it changes back to the default setting.

(As shown below, the automatic detection fro the SCKO (PSCKAUTO) is disabled, so it doesn't overwrite the DIR Recovered Clock Frequency Settings)

Am i missing something or do i have to alter another register first in order to set the proper multiplier for the SCKO clock?

Thanks in advance,

George

 

  • 0
    TI__Guru 57800 points

    Hi, George,

    I have notified one of my colleagues to take a look to your problem, he will get back to you soon.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    TI__Mastermind 28020 points
    Hi George,

    Sorry for the delay in response, this is the only register that is needed to change that should effect the recovered clock. You could try writing to the register in script format in the script menu, then read it back to make sure it changes. When you do change the setting in the Register Inspector, are you able to see a change in the clock that is output before it changes back?

    Justin
  • 0 in reply to Justin Bohr
    Prodigy 220 points
    Hi Diego, Justin,

    Thank you both for your replies and i also apologise for the long delay but i was out of the office.

    Justin, i did try to write to the register via the script menu and validate that the register was actually written correctly, and also observe the SCKO frequency with an oscilloscope.

    When i changed the register value from the "Register inspector", the SCKO frequency remained the same all the time.

    Best regards,
    George