ADAU1701 and multible i2S inputs
Hello again, I mangaed to get a APM2 from wondom (ADAU1701) up and running with a PCM5102 DAC from aliexpress and a WM8782 ADC from Audiophonics. This is all described in detail here: ADAU1701 as master and WM8782 ADC and PCM5102 DAC as slaves possible?
Now my next question is: Is it possible/how do I connect a second and different i2S input device?
I was hoping to be able to connect a "Tinysine Toslink Bee" like this:
But seeing that it only has BCLK, LRCLK and DATA connections im, expecting them to be outputs and that the board has its own MCLK onboard, though I see no crystal. I guess I cannot use this module as I will need a module where I can inject LRCLK and BCLK from my ADC and just get the data out right? Or am i still misunderstanding the master, slave clk relations?
Thanks in advance!
Thread Notes
santha.vijay - Moved from Processors and DSP to SigmaDSP Processors & SigmaStudio Dev. Tool. Post date updated from Wednesday, October 30, 2024 7:34 AM UTC to Friday, November 1, 2024 6:22 AM UTC to reflect the move.
santha.vijay - Moved from Processors and DSP to SigmaDSP Processors & SigmaStudio Dev. Tool. Post date updated from Friday, November 1, 2024 6:22 AM UTC to Friday, November 1, 2024 6:22 AM UTC to reflect the move.
Audio Signal Processors
hardware
i2s
SigmaDSP Audio Processors
Tinysine
Bee
toslink
adau1701
1701
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Looking at this it might actually work if i connect the lrclk and bclk from the ADC right?
Hello Danner,
Sorry I missed this old post.
It does look like they drew the diagram showing the clocks coming into the part. This means it would have to have a sample rate converter and I am guessing it does not. So I do not think it will work. I think you will either get nothing or lots of noise and clicks and pops.
You know the easiest way to do this is to use the ADAU1452 which has SPDIF inputs built in and has sample rate converters.
The ADAU1701 is a great part, I love it but the serial port is rather primitive and you do not have any sample rate converters.
One option you could use is to use the bit clock out of the module to drive the MCLK input of the ADAU1701. Then it will be in sync with it at all times. The only problem is if the BCLK stops when there is no SPDIF signal present? There is a mention of an ADC on the board so maybe the clocks are always present? Also, if the sample rate changes then you would need to change the PLL setup pins on the ADAU1701 and restart the part. Not very practical. I go back to say to use the 1452.
Dave T
No worries, I also forgot to get back.
It actually did work. I connected the LRCLK and BCLK from my ADC board into the SPDIF reciever board and then to the ADAU1701 board. The ADC was set as masterunit so it generated the LRCLK and BCLK signals (as far as I understand) based on the MCLK found on the ADAU1701 board and it worked like a charm.
However, this was just to learn about I2S, ADAU dsp's and get started. This isn't elegant and signal integrity is probably questionable at best from what I know know.
But as you might have realized, I am working on a 1452 board. One of the primary reasons for this is to have a DSP with Built in SpDif support. Thanks for the help with that design!
Daniel
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