STM32 UART at 20 Mbps

[AncoMarzio]

Hello,

I'm looking for an STM32 evaluation board that supports UART communication at 20 Mbps. Ideally, having two separate UART ports would be nice, but one would also work.

I've read that the STM32H7 family supports higher UART speeds, but it seems they max out around 12 Mbps. If no MCU supports this rate, would it be possible to overclock an MCU to achieve a higher UART data rate?

Thanks in advance for your help!

[gbm]

To achieve 20 Mb/s, STM32 UART must be clocked at 160 MHz. Really strange idea, even if possible.

[Tesla DeLorean]

Explain WHY?

20 Mbps is just rediculously high for async comms, most use synchronous methods, and ones where data integrity is slightly higher up the priorities list. And PLL's are used rather than shot-gunning the edges and sample points.

The accuracy and stability of the clocks at both ends becomes very important.

.. man with two clocks never knows exactly what time it is exactly ..

Segal's Law

[AncoMarzio]

@gbm @Tesla DeLorean  thanks for your answers.

I have a UART to RS422 transceiver that reach a 20Mbps data rate.

In the final architecture, I do not have problems to reach such UART speed, but I'd like to test the transceiver first while keeping costs as low as possible. An STM32 Nucleo evaluation board seems like the best fit for this test (and for additional tests I’ll be conducting later).

@gbmis it possible to clock the STM32 UART at 160 MHz? Have you tried this before? Is the STM32H7 family a good fit for this test?

[mƎALLEm]

Hello,

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@AncoMarzio wrote:

@gbmis it possible to clock the STM32 UART at 160 MHz? Have you tried this before? Is the STM32H7 family a good fit for this test?

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You didn't mention which H7 device you are referring to. But for STM32H74x/STM32H75x you cannot exceed 125MHz at VOS0 from RM0433.

[waclawek.jan]

LPUART may be more flexible in achieving high baudrate-to-clock ratio, for example this is quote from the 'L4 RM:

That does not mean it's a good idea overall.

JW