XCORE Mic array

Voice related projects and technical discussions
bcmoore
Junior Member
Posts: 5
Joined: Fri Feb 16, 2018 3:28 am

XCORE Mic array

Postby bcmoore » Sun Feb 25, 2018 7:54 pm

Hi all. I want to create a project based on your XCore mic array board, but with the following changes:
I don't need Ethernet. All connectivity will be via USB. I want to delete all the Ethernet circuitry.
In addition to the analog audio output DAC, I will need to input to the XCore, along with the 7 PDM mics, I2S audio from an audio ADC. Thus I will need an additional I2S port for input. So that I will have the 7 mics plus one analog stereo pair for input, and one analog pair for output.
To save cost and programming, I also want to eliminate the CS2100 and use just an oscillator to generate MCLK and the tile clk.

My questions:
Are there any restrictions or recommendations as to what pins I can use for the additional I2S input port? The I2S output, input, and the PDM mics must all be available simultaneously. I plan to keep the pin assingments on your mic array board for the PDM mics and I2S for the audio DAC. I can use the same MCLK, LRCLK, SCLK, etc. for both ADC and DAC; they can both be slaves.
What is the frequency that the CS2100 is outputting?
I am in the process of creating a schematic to have a board made; whilst that is being done I plan to start developing the code. So I want to know if my goals are feasable before I have a board made.
Thanks.
Regards, Brian
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infiniteimprobability
XCore Legend
Posts: 1120
Joined: Thu May 27, 2010 10:08 am

Postby infiniteimprobability » Mon Feb 26, 2018 5:12 pm

My questions:
Are there any restrictions or recommendations as to what pins I can use for the additional I2S input port? The I2S output, input, and the PDM mics must all be available simultaneously. I plan to keep the pin assingments on your mic array board for the PDM mics and I2S for the audio DAC. I can use the same MCLK, LRCLK, SCLK, etc. for both ADC and DAC; they can both be slaves.

Any spare 1b port on tile[1] where I2S is. All 1b ports behave the same so choose one that is most convenient for you.

What is the frequency that the CS2100 is outputting?

Take a look in customdefines.h. There you will find the MCLK defines. For mic array, it's the MCLK_48 that is normally used as this will divide down to produce the 3.072MHz needed by the PDM mics.

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