Nucleo-U575zi-q STlink via USB not working at any setting other than sysclk=4MHz, Baud=115200.

[Tjohn.1]

I have setup the STlink to communicate to TeraTerm to use printf/scanf. This works at the default clk (4MHz) and 115200 Baud. This does not work at any other sysclk freq or baud rate.

I have verified the clk setup and usart setup & communications using a protocol analyzer (and a scope) via the usart rx/tx pins (PA8/9). The rx/tx signals are correct for multiple sysclk freq and baud rates and the protocol analyzer correctly interprets the messages.

I suspect something is happening between the Usart and the USB port but can't figure out what.

This is for an EE class I am developing and uses register level programming and not the STM HAL.

To repeat - the USART RX/TX signals work for many variations, the USB only seems to work for 4MHz/115200 Baud.

[TDK]

Probably a clock issue, especially if "not working" means garbage characters on the terminal. Ensure sender and receiver are set for the same baud rate.

You're an EE (or about to be, presumably), put a logic analyzer on the line to figure out what's going on.

> protocol analyzer correctly interprets the messages.

Oh, seems you've done that. If the signal coming from the STM32 is good per the analyzer, then the issue is with the receiver. Again, probably a clock issue.