How to send 24bits & n slots TDM from i.MX6DQ SSI.

[satoshishimoda]

Hi community,

I have a question about i.MX6DQ SSI.

Please see the attached file, it shows the format our partner want to output.

I want to know what mode and how should I set SSI register since I feel SSI network mode cannot output it even though it is TDM.

According to the explanation in chapter 61.8.1.4 of IMX6DQRM, I guess it is possible if I set SSI = I2S master mode (I2S_MODE[1:0]=01b), WL[3:0]=1011b(24bits/word), and DC=n-1.
(Please note that the polarity and position of LRCK)

Is my understanding correct?\

Or LRCK toggles for each word and cannot send 3 or more slots in I2S master mode?

Best Regards,

Satoshi Shimoda

[igorpadykov · Accepted solution]

Hi Satoshi

>LRCK toggles for each word and cannot send 3 or more slots in I2S master mode?

yes, since according to I2S specification (sect.3.2)

https://www.sparkfun.com/datasheets/BreakoutBoards/I2SBUS.pdf

only two channels can be used right and left. Also from i.MX6DQRM

sect.61.8.1.4 I2S Mode  :

The word length is fixed to 32 in I2S Master mode and the WL bits determine the number

of bits that will contain valid data (out of the 32 transmitted/received bits in each

channel).

Best regards

igor

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[satoshishimoda]

Hi igor,

Thank you for your reply.

I understood I2S master mode cannot send the attached format.

Then, how about other mode?

Does i.MX6 have a mode to output the attached format?

Best Regards,

Satoshi Shimoda

[igorpadykov]

Hi Shimoda

I think you can consider network mode.

Best regards

igor

[satoshishimoda]

Hi Igor,

Thank you for your prompt reply.

> I think you can consider network mode.

Unfortunately, I found i.mx6 SSI in TDM mode and the answer for this post said "it is not possible to extend (or pad in some way) it to 32 bits.".

So I think it is no way to output the attached format if I2S mode cannot do that.

Best Regards,

Satoshi Shimoda

[igorpadykov]

Hi Satoshi

right, 32bits is not supported in SSI.

Best regards

igor