STM32WB55 max LPUART speed

[JDoum.1]

Hello,

I was wondering what the maximum transfer speed is of the single wired (Half-Duplex) LPUART connection of the STM32WB55CGU. The clock configuration shows a clock frequency of 64Mhz, the baud rate is by default 209700 Bit/s. Is it possible to transfer at 1Mbit/s, or more?

Thank you!

[Bubbles]

Hello @JDoum.1​ ,

yes, speeds above 1MBaud are possible. Theoretically you can go up to speed of (peripheral clock/3) which is in your case something above 21Mbaud.

But the LPUART is designed rather for low speed/low power consumption scenario. At extremely high speeds it will have higher error rates than regular USART peripheral, which features baud rate auto tuning and oversampling to improve com reliability.

If speed is the goal, consider normal USART peripheral in asynchronous mode.

Rgds,

J.

[JDoum.1]

Thank you very much!

Do you also know what the difference is between single wired UART and single wired USART?

[Bubbles]

Hello @JDoum.1​  - I don't think single wired USART is a thing. But the USART peripheral (I believe all those STM32 are using) can also be used in asynchronous mode, making it practically an UART. You do not need to restrict your design to LPUART to communicate single wired half duplex.

Both LPUART and USART peripheral will easily go above 1Mbaud, but I expect the USART peripheral to have better results as UART at very high speeds.

J.