SAI for 8 channel TDM?

[SKarl.3]

Hello,

I'm spec'ing a system where we would need to interface 4x eight-channel ADCs with an MCU for audio capture. Simultaneous capture on all channels is an important requirement.

Currently we are considering the STM32H750VB MCU which has 4x SAI interfaces, and the Analog Devices AD7768. All ADCs would be running at the same time, synchronized, and the data from them would be DMAed into ring buffers.

I'm not familiar with the ST SAI interface. It seems like they can support 8 channels in TDM mode (which that ADC supports), but I'm not sure?

Can this be done with the STM32H750VB?

[soufiane]

Thank you very much that was very helpful , would you mind sharing any source code or repos for your prior application with the ads1278 and h743 , can I use only two SAI , SAI1 ( with two both blocks) and SAI2, would it be better than raw spi and write my own tdm and parsing code ?  

[bmckenney]

The code is owned by someone else, so I can't publish it. I think I can say that the SAI setup, including MCLK, DMA, and ISRs, is less than 100 lines of code (no HAL).

You could (I think) do everything the SAI is doing, but the SAI will do it more simply and reliably. Once started, it runs itself and periodically presents blocks of (isochronous) data.

I expect you could use the SAI A and B sides as 2x SAIs, though I haven't tried it.