Electronic – Is the GPIO speed involved in the baud rate of the USART

armembedded

I am working with am ARM Cortex M3 where two GPIO pins are configured as Alternate Function for use as USART pins. When setting the pins as Alternate Function, I have to set the Output Speed of those pins. (I set them at 50Mhz.)

Reading the reference manual (available here) on pages 613 and following, the baud rate of the USART seems to only depend on the APB1 clock rate f_CK.

Does the set GPIO speed influence the USART baud rate?

Best Answer

From what I understand, output speed is the update rate of the output. As long as it is reasonably higher than the the rate at which your output changes, it shouldn't matter too much.