I asked this a month ago, but didn't get an answer and so the thread was auto-deleted. It is becoming critical that this be solved, so I am reposting.

I have the simple sound card working with a fixed 192KHz. I need to have it able to dynamically switch frequencies via the i2c interface. How do I set that up?

More Details: I am using a device tree with a i2s slave simple sound card. It is pumping audio to a SHARC 489 processor. Since this is a RoonBridge application, I need to have it appear as a sound card to the Roon software. To do that, I need to be able to change frequencies from the default 192KHz down to 96KHz, 48KHz, 44.1KHz, etc. To do that I have the i2c interface all connected as per the RPi specs and it shows up with i2cdetect. But the problem is that nothing is sent via i2c when I change the frequency.

I am hoping someone has already done this so there is an example, or there is some documentation somewhere (I have been searching for months and only can find obscure references).

Thank You, -Erik

  • 1
    it is unclear what you are asking ... you refer to I2C and I2S ... also, you did not say if the "simple sound card" has I2C interface or an I2S interface .... are you certain that the hardware is capable of doing what you are wanting to do – jsotola Jul 29 '19 at 23:19
  • @Erik, Well IEEE 802.3bt 4PPoE 2018 specifies 50W 900mA. So you can extract the power, regulate it (Note 1) say, to 5V or higher to charge your Lipo thing. Of course you need to DIY your own hat. Note 1 - Common commercially available DC/DC modules use LM2596 or similar, accepts input up to 40V, so you need to be very careful to get a higher input regulator, or it will explode! :) – tlfong01 Jul 30 '19 at 1:50
  • tlfong01 - ??? I think you misposted. – Erik Jul 30 '19 at 15:06
  • jsotola - the "simple sound card" is a i2s sound card built into the kernel. I am assuming it has an i2c interface - if not, then I will have to get into writing a driver - ug. Somehow HiFiBerry does it. – Erik Jul 30 '19 at 15:09

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