How to run UART on STM32H755 with speed above 1M baud rate

[Ruồi]

Hello Experts,

I am having problem with uart on stm32h755, nucleo kit.
I use uart1 and uart2 to communicate with each other using DMA.
When I set the baud rate above 1M baud rate it doesn't work. Below is the clock configuration.

And here is the UART configuration.

Looking forward to receiving any help.

Thanks,

RUOI

[Tesla DeLorean]

How does "doesn't work" manifest?

The receive is problematic? The transmit? Over / Underrun?

If you transmit a constant 0x55 ("U") pattern, can you check the frequency with a scope?

As the rates increases the frequency error can get larger / rougher. You want a bus clock that's closer to a multiple of 16 MHz for 1 MHz, in 16 Over mode.

If using RS232 level shifters, these have bandwidth limits around 1 Mbaud.

[Ruồi]

Dear Tesla DeLorean,

I just transmit from UART1 to UART2 and transmitted back.

Below is the code that performs the transmission and reception.

The problem is when I increase the baudRate to 2M the variables send_data, receive_data, echo_receive_data do not change. When I set the BaudRate to 1M, the variables change, proving that the UART is working.

Looking forward to receiving any help.

Thanks,

RUOI

 

[FBL]

Hello @Ruồi 

Baud rates at this level are not guaranteed to work reliably. You may need to rework your PCB to get better responsiveness.

[David Littell]

I would suggest that if you really want to run that fast you should be using synchronous or switch to SPI.