LPC55S28 USB Aduio class is abnormal after modifying the format of audio data

[MHY_0878]

Hello NXP seniors, I have changed the format of USB audio data on the official SDK of LPC55S28.
My main problem is modifying the audio stream format type descriptor.
My idea is to change the number of bytes of data per channel of USB Aduio from 2 bytes to 3 bytes (from 16 bits of valid data to 24 bits of significant data).After changing the bSubframeSize (0x10 changed to 0x20), the speaker logo on the computer disappeared (the USB enumeration passed, but the function was not implemented).
I would like to know, the format changed from 16 bits, sample rate 48khz to 32 bits, sample rate 48khz, in addition to modifying the audio stream format type descriptor, where else to achieve my goal.
Attach my code.
 

[EdwinHz]

Hi @MHY_0878,

The following community post has an example code for the RT1010 that shows the necessary changes for 24-bit audio through USB Audio Class. Please look into this example code, as the changes are the same for the LPC55s28: Solved: I.MX RT1010EVK USB Audio 24 bit ? - NXP Community

BR,
Edwin.

[MHY_0878]

Hello, I have downloaded your code according to your link, only changed the configuration descriptor and data format length, the computer can display 24 bit depth and 48kHz sample rate. But I used an I2S with an MCLK of 12.288Mhz, a BCLK of 3.072Mhz, and an LRCLK of 48khz to send the data from the PC to the MCU, and the sound of a shalala appeared after the data came out of the ADAU1761.

With my MCU code and SIGMA STUDIO project, this issue has been troubling me for several days. Could you please help me take a look?