STM32 GPIO Speed - hampussandberg/HexConnect GitHub Wiki
The measurements were done on a STM32F429 Discovery Board using pin PG5 because that pin was close to a GND pin on the header. It is using an external crystal of 8 MHz and the PLL inside is set to output a 180 MHz SYSCLK. A Rigol DS1054Z was used to do the measurements.
GPIO_Speed_2MHz (GPIO_Low_Speed):
Rise time ≈ 9.5ns
GPIO_Speed_25MHz (GPIO_Medium_Speed):
Rise time ≈ 3.7ns
GPIO_Speed_50MHz (GPIO_Fast_Speed):
Rise time ≈ 2.4ns
GPIO_Speed_100MHz (GPIO_High_Speed):
Rise time ≈ 1.9ns