Step at a time...
Have you tried the demo on hardware?
It gives a short LED flash every half second.
Gives a long (half second) flash of the LED when the interrupt input is triggered.
What do you see?

Here's an EXTI demo for the 32F411 BlackPill dev board ...

Thanks for the further info.
I'm not sure what support there is for interrupts in simulation mode - one for the Matrix team.
I should be able to find some time next week to provide an EXTI example on STM32F411 hardware

I suspect there might already be examples on this or the old forum. Just some other points... Presumably you have proved that the hardware is working? Perhaps adding a led flash in the main loop. Are you using your own hardware design, or a development board? You have a pull up (or down) resistor on...

As far as I can see, from the attached C file (and the fcfx) you have EXTI0 selected, not EXTI1 that is required for PA.1
Can you recheck this?

Hi,
Interrupts do work on F4 series, unfortunately I personally won't be able to check your Flowcode project this week, someone else might be able.
If you want to post the generated C code, I might be able to deduce something from that.

I'm not near my pc at the moment so can't check your project file, but a couple of things to check ... For the interrupt are the properties set to EXTI1 and Port A? The Flowcode project "clock speed" setting needs to be set at your external crystal frequency (8MHz, 16MHz etc) Hope that helps

Please try the attached file update,
to go into directory
C:\Program Files (x86)\Flowcode\Common\Compilers\starm\src

nb. delete all previous build files before you re-build the project

Ok. Thanks for the feedback.
I should be able to get back to my PC sometime in the next day or two and have a look at the interrupts, it's a shared one on this device, so a little more complex

Thanks. Yes, if you confirm that it fixes the issue then Matrix team can update their versions.