SAI1 controlling multiple chips?

[chect1]

SAI1 has 5 pins: 1 Tx, 1 Rx, 3 flexible

I need to control 32 Outputs and 6 inputs with this SAI if possible. (I am using SAI4 for additional lines and SAI2+3 conflict with the data pins for the SDRAM)

I'd like to use 3 Tx pins to control 3* PCM1681 chips and 1 Tx and 1 Rx pin to control a PCM3168A chip

I will be running all chips at the same data rates, same speeds, synchronized. 16 bits, 48kHz.

Is there any reason I can't use all 5 SAI1 pins like this to control different chips? The clocks should be the same, the TDM will be the same format (does that matter?).

Thanks!

[kerryzhou]

Hi @chect1 ,

  Please tell me which RT chip partnumber you are using now?

  You mentioned SAI4, seems you are using the RT11XX, now, take the RT1170 as an example, the SAI situation is like this:

About the SAI1, although it is 5 data pins, but, to the TX, the max is 4 data pins, so you can't use 5 TX dataline in the SAI1, you also need to use other SAI interface.

You mentioned:I'd like to use 3 Tx pins to control 3* PCM1681 chips and 1 Tx and 1 Rx pin to control a PCM3168A chip

=>I think you can use 3TX pin control 3 PCM.

Wish it helps you!

If you still have question about it, please kindly let me know.

Best Regards,

Kerry

[chect1]

Yes the RT1170

I only plan on using 4x TX lines and 1x RX line on the SAI1 peripheral:

3x Tx control 3 PCM1681 chips, each one TDM, 8 DAC outputs

1x Tx + 1x Rx to control a PCM3168A chip

That totals 4 Tx pins and 1 Rx pin

I think we are saying the same thing. SAI1 can control 1 fixed Tx, 1 fixed Rx and 3 flexible pins. 

[kerryzhou]

HI @chect1 ，

  Yes, so do you still have any future issue about this topic?

  If yes, please kindly let me know.

Best Regards,

kerry

[chect1]

I am using the RT1170, like you used in your example

You said that I can use 3 Tx pins at once, that is great

I want to know if I can use the 3 Tx pins on 3 chips and the last Tx+Rx pin on a 4th chip PCM3168A

All of them with TDM, all with their own DMA, all 5 pins at the same time

Are there any issues with this?

[kerryzhou]

Hi @chect1 

You mean, the RT  3 SAI_TX_DATA pin connect to the external 3 chips, then another SAI interface TX, RX connect to the 4th external chip, right?

Of course, you can! You can configure the related DMA, it's OK.

Wish it helps you!

If you still have question about it, please kindly let me know.

Best Regards,

Kerry

[chect1]

Thank you! Very helpful. I'll give that a shot on the first board

[kerryzhou]

Hi @chect1 ,

  You are always welcome!

  If you still have question about this case, please kindly let me know.

If your question is solved, please help to mark the correct answer, just to close this case.

Any new issues, welcome to create the new question post, we will help you in your new question post, thanks.

Best Regards,

Kerry