PCM9211: AUX Clock

Franz Schellhase

Expert 3605 points

Part Number: PCM9211

Hi team,

Can you help my customer with their inquiry?

I would like to connect the PCM9211 via I2S with the CS42L51 device.

The CS42L51 has a classic I2S port as I know it:
Master clock
Bitclock
LR-Clock
Dout
Din

However, the PCM 9211 provides separate interfaces for PCM data, i.e. AUX in (I2S in) and Aux out (I2S out).
Where do the clocks for the AUX in on the PCM9211 come from?
Do they have to be connected to the clock lines of the main out?

Thank you,

Franz

over 4 years ago

0 Zak Kaye over 4 years ago

TI__Mastermind 23050 points

Hey Franz,

The interfaces for these two ports are separate. If they want data from the CODEC as well then they could route this to one of the MPIO ports as shown and tie the clock pins of the main output port to the MPIO lines they are using for AUXIN. The part will not internally synchronize the AUXIN port to the clocks on the main output

Best,

Zak

0 Torsten Roeder over 4 years ago in reply to Zak Kaye

Prodigy 90 points

Hey Zak,

thanks for your help. I made a new drawing. If I understand you correctly, we can do it like this, right?

Best Regards,

Torsten

0 Torsten Roeder over 4 years ago in reply to Torsten Roeder

Prodigy 90 points

0 Torsten Roeder over 4 years ago in reply to Torsten Roeder

Prodigy 90 points

0 Zak Kaye over 4 years ago in reply to Torsten Roeder

TI__Mastermind 23050 points

Hi Torsten,

Yes, that is what I had in mind.

Best,

Zak

0 Torsten Roeder over 4 years ago in reply to Zak Kaye

Prodigy 90 points

Thanks for your answer, Zak.
So let's do it this way.

0 Torsten Roeder over 4 years ago in reply to Torsten Roeder

Prodigy 90 points

Hello Zak,
we will not use the internal ADC of the PCM9211 and therefore connect VCCAD with AGNDAD, according to the data sheet note. What to do with pin VCOM, also to AGNDAD or leave open?

Best regards,
Torsten

0 Zak Kaye over 4 years ago in reply to Torsten Roeder

TI__Mastermind 23050 points

Hi Torsten,

The important thing is to connect VCCAD with AGNDAD. The VCOM voltage is derived from the VCCAD supply so it will not be active if you have done this. The VCOM pin is just used for bypassing the internal reference, so without VCCAD you should be fine to either float or ground it.

Best,

Zak

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PCM9211: AUX Clock