STM32 RS485 interface with 12MBit/s

JR1 · ‎2024-09-19

Hello team,

is one of the STM32 MCUs suitable to run a RS485 interface with 12MBit/s? This is related to a UART interface which should be clocked by at least 192MHz.

Best regards,

Jochen Ruopp

waclawek.jan · ‎2024-09-19

> For H74x/H75x, the UART speed could reach 12.5Mb/s.

IMO that's only for the synchronous mode, as that's the only mode which is then characterized in the Electrical characteristics chapter of DS (even if that chapter does not say this out aloud, that's what the diagrams and parameters are all about). And even for synchronous mode, I don't understand how would that be attained, given kernel clock -> baudrate limitation below:

The max. UART/USART kernel clock, according to Kernel clock distribution overview table in RM0433 is 125MHz and the minimum UARTx_BRR is 16, thus maximum baudrate is 7.8125MHz.

Prove me wrong.

JW

View solution in original post

SofLit · ‎2024-09-19

Hello,

For H74x/H75x, the UART speed could reach 12.5Mb/s. Refer to the datasheet.:

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.

waclawek.jan · ‎2024-09-19

> For H74x/H75x, the UART speed could reach 12.5Mb/s.

IMO that's only for the synchronous mode, as that's the only mode which is then characterized in the Electrical characteristics chapter of DS (even if that chapter does not say this out aloud, that's what the diagrams and parameters are all about). And even for synchronous mode, I don't understand how would that be attained, given kernel clock -> baudrate limitation below:

The max. UART/USART kernel clock, according to Kernel clock distribution overview table in RM0433 is 125MHz and the minimum UARTx_BRR is 16, thus maximum baudrate is 7.8125MHz.

Prove me wrong.

JW