DS90UB941AS-Q1: I2S splitting with 2:2 independent mode

LFA

Part Number: DS90UB941AS-Q1

Hello,

I plan to use a DS90UB941AS-Q1 in 2:2 independent mode to drive two displays with different resolutions.
I also need to transmit two audio channels per display which, on the deserializer side, should be "regenerated" on the same pin for both displays.

Reading chapter "8.3.11.1.3 Audio During Splitter and Replicate Modes" of the DS90UB941AS-Q1 datasheet, it seems to describe this usecase, however only for the splitter and replicate mode.

Question 1:
Is my understanding of "Table 8-7. Splitter Audio Channel Mapping" correct, that when AUDIO_SPLIT is set to one, the mapping is done as shown in the following diagram?

Question 2:
Is splitting audio also supported in 2:2 independent mode?

over 4 years ago

0 Aaron Heng over 4 years ago

TI__Mastermind 37550 points

Hi LFA,

Thank you for reaching to us. I will review this, and get back with you by the end of this week.

Aaron

0 Aaron Heng over 4 years ago in reply to Aaron Heng

TI__Mastermind 37550 points

Hi LFA,

Yes, it is possible to split the audio I2S to two different displays using 2:2 independent. Here is additional information.

www.ti.com/.../snla308a.pdf

Aaron

0 LFA over 4 years ago in reply to Aaron Heng

Prodigy 80 points

Hello Aaron,

thanks for the reply.

Can you also confirm that the mapping I posted (I2S_DA on 941 to I2S_DA on 948, and I2S_DC on 941 to I2S_DA on 948) is how the I2S splitting is implemented in the DS90UB941 and DS90UB948 when using the 2:2 independent mode?

The application note you referred to unfortunately doesn't contain any information about audio/i2s as far as I can see.

0 Aaron Heng over 4 years ago in reply to LFA

TI__Mastermind 37550 points

Hi LFA,

Sure. I can provide you the script based on your diagram. Please allow me until 9/30.

Aaron

0 Aaron Heng over 4 years ago in reply to Aaron Heng

TI__Mastermind 37550 points

Hi LFA,

Just want to check with if you have try this in the datasheet. The datasheet describes how to do this in section 8.3.11.1.3.

Aaron

0 LFA over 4 years ago in reply to Aaron Heng

Prodigy 80 points

Hello Aaron,

I didn't try anything on actual hardware yet, as the project is currently in the concept phase and I would just like to confirm that the DS90UB941 can do what I would like.

Regarding chapter "8.3.11.1.3": yes, I've read that and if you read my original post, also explicitly mentioned that section. However (as also written in the original post) there's no mentioned of the "2:2 independent mode" in this chapter (revised datasheet from January 2021); that's why I asked "Question 2" (see above).

This section also contains table 8-7 (which again, I referred to) which I would like a confirmation that my interpretation is correct (see "Question 1")

0 Aaron Heng over 4 years ago in reply to LFA

TI__Mastermind 37550 points

Hi LFA,

Thanks for the confirmation. I will try this on the bench. I will get back with you by Friday, 10/15.

Aaron

0 LFA over 3 years ago in reply to Aaron Heng

Prodigy 80 points

Hi Aaron,

do you have feedback regarding the open questions on the 2:2 independent mode?

0 Aaron Heng over 3 years ago in reply to LFA

TI__Mastermind 37550 points

Hi LFA,

Sorry for the delayed. We had tried on the bench so that we can replicate your setup. We are currently investigate this. We will get back with you ASAP 11/12.

Aaron

+1 Ben Dattilo over 3 years ago in reply to Aaron Heng

TI__Mastermind 25765 points

Hi LFA,

Sorry for the delay. We set this up in the lab and confirmed that your diagram is correct. In independent 2:2 mode I2S_DA will go to port 0 and I2S_DC will go to port 1 when using AUDIO_SPLIT.

Regards,

Ben

0 LFA over 3 years ago in reply to Ben Dattilo

Prodigy 80 points

Thanks a lot for the support.

Would it be possible to provide the register settings or script that you used for the test?

0 Ben Dattilo over 3 years ago in reply to LFA

TI__Mastermind 25765 points

Hi LFA,

After configuring the SER + 2xDES to independent 2:2 mode, and establishing lock, I configured the following for I2S:

Register 0x04 = 0x10 Enable packetized audio
Register 0x12 = 0x00 Data island transport
Register 0x1A = 0x01 I2S surround sound
Register 0x54 = 0x02 I2S input from pins
Register 0x55 = 0x10 Split audio

Regards,

Ben

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DS90UB941AS-Q1: I2S splitting with 2:2 independent mode