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What I am looking for is some open driver that tackles more than just 48 kHz.

Or a trick, if there is one.

PIN30 MCLK gets 24.576 MHz and I have internal counters to count down with, for the speed of the I2S.

DamienD
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Øyvind Teig
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  • Sample rate supported by each input interface: PCM:44.1KHz,48KHz,88.2KHz,96KHz,176.4KHz, 192KHz,352.8KHz,384KHz – Tony Stewart EE75 Dec 18 '21 at 22:20
  • Thanks! As far as I can see in the CS43L21 data sheet there are "sample rate (LRCK)" of 8 to 96 kHz in steps. But this is dependent on MCLK, which on this board is 24576000 Hz from a PLL that may be controlled, though. You indicate some higher steps. It would be great to have this seen in perspective. The circuit diagram is at https://www.xmos.ai/download/xCORE-Microphone-Array-hardware-manual(2V0).pdf – Øyvind Teig Dec 20 '21 at 08:20
  • Sorry for the error in the heading! I'm talking about DAC all the time here, not ADC. I got the letters confused, I must admit. – Øyvind Teig Dec 28 '21 at 19:56

1 Answers1

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As shown in the datasheet, the CS43L21 does not automatically support 8 kHz sampling rate with 24.576 MHz MCLK.

Either halve the MCLK output from the PLL, or enable MCLK dividing by 2 at the DAC in hardware or software, or disable auto-detection and set the MCLK to FS ratio manually.

Justme
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  • Thanks! I think I have done what you state, but I'll fine read your comments and then come back here. Øyvind – Øyvind Teig Dec 30 '21 at 10:50
  • Thanks, @Justme. I do think that should be in place. But in trying to understand what XMOS might have done, and what I have done, I have made a description of it all (PDF), and made my code available. This is just a hobby project with one of the purposes to be shared, with no ads or income from my notes. It's at link – Øyvind Teig Jan 06 '22 at 10:37