[LAU] Sound from/to custom ADC/DAC

Chris Caudle chris at chriscaudle.org
Tue Mar 13 04:50:06 CET 2018

On Sun, March 11, 2018 10:03 am, pepijn de vos wrote:
> I was unaware of I2S, it seems perfect for our purpose!

How are you getting audio data into and out of the FPGA?  Nearly every ADC
and DAC chip uses I2S as the transfer protocol, unless it is a large
multichannel chip, in which case it probably uses TDM, which is just the 4
or 8 or 16 channel version of I2S.  Very odd that you could be working on
audio hardware and not come across I2S.

> My main concern is that I need more than two input channels and at least
> one output channel.

You either use multiple I2S connections, or you use a mode which supports
multiple channels.
I think the multichannel configuration is in the Sitara processor (BBB)
documentation as McASP or something similar.   Look in the ALSA tree in
the SoC drivers to see if there is a driver for Am335x or Sitara.  Might
only be two channel, I haven't had a chance to check yet.

Chris Caudle

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