SPDIF TX: Channel Status Data gone when changing UART speed

[LCE]

Hi,

I'm currently using an STM32G431 on a Nucleo-32 board, connected to an external audio ADC and transmitting ADC audio data via SPDIF, all audio stuff running with 192kHz.

Toolchain: CubeIDE, design started with CubeMX.

In the DMA TX half complete / complete ISR the ADC data is shifted and channel status bit is added.

So far, so good, works like a charm.

Yesterday I changed UART speed (the virtual COM port via the Link-MCU) from 921600 baud to 115200 baud, today I see that the channel status data is missing, although audio data is still tranmitted correctly.

As I haven't changed anything else I switched back the UART to 921k6, and surprise, channel status data is back.

Any ideas what's going on there?

[LCE]

It's the frame count offset again.

But why does that depend on the baud rate?

I stopped all UART outputs when starting SPDIF, still the same problem.

UART TX for printf is running in DMA mode, lower priority than SAI.