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STM32F407 and TDM or multiline I2S (DAC/ADC)

Question asked by burnett.rick on Aug 27, 2013
Latest reply on Aug 28, 2013 by burnett.rick
Hello!

I've been wanting to increase the ADC/DAC setup in my design using the STM32F407 chip but I am having a hard time understanding what specific functionality I can use to get more than 2 in / 2 out over a single I2S implementation.

Given that the evaluation board was using the Cirrus Logic DAC (and ADC) I started looking at their other solutions which I found quite a few that I liked.  Unfortunately, I found that if I wanted to use I2S, that each stereo pair comes out it's own separate data line.  I don't see any mechanism within this STM32 chip to support parallel I2C data sends.  The next thing I saw is that most of their chips do 256xFs TDM mode (also called DSP mode by some manufacturers it looks like) but I cannot figure out how I would use TDM without just using bit-blasting which then would most certainly mean I cannot use DMA transfers to free up the processor.

Clearly I must be missing something here.  Also, I don't understand why I2S2 and I2S3 are on the same DMA channel?  I would think I'd like them to both go in and out at the same time.  Unless the memory access is so fast, that they can work concurrently since I2S is so much slower they just sort of interleave on their own.

Any suggestions?

What I was trying to use is
CS5366 ADC (6 channel ADC in) and  CS4365 (6 channel DAC out).  Not even sure if there is like a TDM to I2S converter (both direction) that I should be considering.  I searched quite a bit on these things and found nothing.

Thanks for taking a look!
Rick

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