USB FS + I2S_CKIN

[stop]

I want to have asynchronous USB audio with the STM32g431k6 and an external DAC but I get conflict message if need both. Am i missing something? if i use OSC IN as audio clock input it will not bypass the internall PLL as in I2S_CKIN isn’t it? I thought it was due to the product used (32pins) but with the 48 is the same. So the question is how do i do that?

[mƎALLEm]

Hello ​@stop and welcome to the ST community,

If I understood well your request, you need to use I2S_CKIN in parallel with USB with a STM32G431 / LQFP32 package.

if i use OSC IN as audio clock input it will not bypass the internall PLL as in I2S_CKIN isn’t it?

Yes indeed. Why don’t use an external clock with HSE bypass configuration and feed the I2S clock with PLLQ. Prioritize the value of the I2S clock value selection versus the system clock. Use I2S3 instance:

Don’t have idea about the standard I2S clock values but this is the clock config with I2S and USB clocks set at 48MHz:

If this is not convenient for you, use a bigger package for example LQFP64 or LQFP100 where you have I2S_CKIN and USB_DP IOs are not sharing the same pin: