EXTI Edge Detection Characteristic for STM32H7 - rise/fall time?

[NickO]

I am trying to detect both rising and falling edges on a GPIO input using EXTI.

I am using a STM32H755 (144 pin) - SYSCLK is 400MHz, but I am using the CM4 core, so the CPU clock is 200MHz. APB Timer clock is also 200MHz.

The signal I am monitoring is coupled through an opto-isolator, and having scoped it, seems to have a rise-time of approx. 5us. I am wondering if this is too slow for EXTI rising / falling edge detection?

I've been looking at both the datasheet and reference guide for the STM32H755 and I could not find any data on max and min rise times for edge detection to function reliably.

[RobK1]

The digital I/O pins have a Schmitt trigger input, as witnessed by this characteristic:

(Page 151 of the datasheet)

So rise- and fall times should be no issue.