nrf5340 usb device for audio

[huma]

I have found that nrf5340 support the usb device function. It can be used for sound card which can receive the audio signal from the PC, and output the mic signal to PC.

And I have tested that function from the nrf5340_audio application.

My question is if we made a USB Docking, if i plug my device which uesd nrf5340 to the docking, can output music(for example, the i2s input to the nrf5340) to the docking which can convert it to analog signal so people can hear them through the wired headset.

Because i thought that first, may be the Docking shoud support the USB HOST function, and the second question is we need the nrf5340 to output the audio signal through the USB prot, not only the MIC signal, I don not know if there some limtations in that.

Thank you very much for helping.

[ace.johnny]

 huma , I've been following this thread with interest, wondering whether you'll be able to transceive all 8 I2S channels to the PC.

I'm not sure if you're still having issues with mono/stereo signals, but here's something worth considering. While the CS47L63 has 2 stereo inputs (IN1 and IN2), only IN2 is wired for analog stereo line-in.

IN1 is wired to the digital mic, which is a mono signal and only outputs on the IN1L channel. When the PDM mic is selected, hw_codec.c writes register values that assign the silent IN1R channel to ASPTX2 I2S.

If you want the PDM mic to fill both L/R I2S channels, you'll have to edit cs47l63_reg_conf.h so that IN1L is routed to both ASPTX1/2.

cs47l63_reg_conf.h line 75:

/* Send PDM MIC to I2S Tx */
{ CS47L63_ASP1TX1_INPUT1, 0x800010 },  // IN1L
{ CS47L63_ASP1TX2_INPUT1, 0x800011 },  // IN1R

Change to:

/* Send PDM MIC to I2S Tx */
{ CS47L63_ASP1TX1_INPUT1, 0x800010 },  // IN1L
{ CS47L63_ASP1TX2_INPUT1, 0x800010 },  // IN1L

Hope this helps. Good luck, and keep us updated!

[huma]

Hello,

Thank you very much! But I haven't delved so deeply into your research yet. At present, I have not been able to make the computer recognize USB devices as multi-channel devices.  Once I achieve this goal, I may start researching how to handle the audio part.

May I ask if you have a way for the computer to recognize that USB devices have multiple channels？As long as the computer can correctly recognize them, my first goal can be achieved.

Thank you very much!