Nucleo STM3H723 UART Single Wire (Half Duplex) Frame Error

[MFäh.1]

Hi,

I am experiencing issues with UART single-wire (half-duplex) communication on an STM32H723. The UART handler reports error code 4 (frame error). I have tried a wide range of configuration settings without success.

The same setup works correctly on an STM32F439, but not on the H723. Do you have any suggestions on what I could try or what might be causing this behavior.

BR 

[TDK]

If it reports a frame error, maybe there's a frame error. Can you see what is happening on the line with the help of a logic analyzer? Are you sending data or receiving data?

[MFäh.1]

I can decode the signal perfectly with a PicoScope and consistently observe the correct data. At the moment, I am only receiving data; however, at a certain point I also need to transmit data.

[TDK]

Perhaps the baud rate is incorrect due to a clock configuration issue. Try sending data and verifying the baud rate is as expected.

You will also get a framing error if the peripheral is enabled in the middle of a byte as opposed to when the bus is idle.