RT1064: Is it possible to use DMA to service two separate SAI buses at the same time?

[mrecoskie]

Hi,

I have tried using the DMA HAL API to service two SAI buses (two separate attached codecs) on the RT1064 however I seem to be running into limitations.  Is it possible to use DMA in this scenario and has anyone successfully made this work?

Regards,

Mark

[mrecoskie]

Hi,

Thank you for the response.  This sample uses the low level DMA API. 
Does it not suffer from the same limitations when used for both SAI1 and SAI2 at the same time?

Mark

[Pavel_Hernandez]

You can connect the different SAI interfaces to the available eDMA Channels.
It's important to add the eDMA can only dispatch one at time.

If you have more question don't hesitate to ask me.
Best regards,
Pavel

[mrecoskie]

Thank you.  Can this be found in the documentation anywhere?

So from my understanding - if I want to achieve different, concurrent audio steams across multiple SAI buses at the same time I should move to an interrupt model.  Is that correct?

[Pavel_Hernandez]

Hello,

The eDMA this post could be help you. Section 2. eDMA Channels - What is and how to configure the eDMA channel link... - NXP Community
You could use a good control of the IRQ. I recommend review this chapter may be help you, 6.4.8 Suspend/resume a DMA channel with active hardware service requests, from the reference manual I add the link below.

i.MX RT1064 Processor Reference Manual (nxp.com)

Best regards,

Pavel

[Pavel_Hernandez]

Hello, 

I found this Application Note, maybe would help you.
Using Multi-Channel Feature of SAI (nxp.com)

Best regards,
Pavel

[Pavel_Hernandez]

Hello mrecoskie

The DMA can't dispatcher at the same time, but I suggest check the example from the SDK sai_edma_record_playback, may help you.

Regards,

Pavel_Hernandez