H743 GPIO EXTI Controller Details

[astral256]

I am using the H743 microcontroller and am looking for some more information about the GPIO EXTI controller.

Specifically, how long does a signal need to be held on a GPIO in order for the EXTI to detect a rising or falling edge?

I notice in the timer peripherals, you can set different filters on the input using the ETF (External trigger filter) bits in the TIMx_SMCR (TIMx slave mode control register).  This way you can decrease the sampling frequency and require multiple samples at a specific polarity before detecting a rising/falling edge.

However there is no information like that for the GPIO EXTI detection.  What I want to know is what is the sampling rate at which the microcontroller samples the GPIO when placed in EXTI mode?  And is it the first sample that crosses the high/low input polarity (~1V for low, ~2.3V for high @3.3V) or do several samples in a sequence need to be detected?

[Chris21]

EXTI characteristics section appears to be missing from the datasheet.

Example from STM32H503xx datasheet:

 

[TDK]

On the F4, it's 10ns. I would guess it's similar here but doesn't seem specified in the datasheet.

 

It is an edge detection circuit--a single event will trigger it. No digital filtering.