In STM32F103,What is the maximum baudrate supported by controller?

[Javier1]

If youre referring to UART badurate, i managed to make bluepills (stm32f103c8 wth 8Mhz xtal) work at 500Kbits

[Peter BENSCH]

You will find the maximum baudrates e.g. in the reference manual of the STM32F103 family:

• USART: 4.5Mbit/s
• SPI, I²S: 36Mbit/s
• CAN: 1Mbit/s

As @Javier Muñoz​ mentioned, you can also see the baud rate with STM32CubeMX or the STM32CubeIDE, whereby the respective clock settings are taken into account. For example, with USART1 at HCLK = 72MHz, APB2 Prescaler = 1, the above mentioned 4.5Mbit/s can be achieved.

Regards

/Peter