STM32CubeMX: "you are in a maze of twisty passages, all alike"

Brief soapbox advice to those new to that tool: it uses a 'progressive disclosure' style of UI design, and distributes pieces of functionality throughout the GUI. This can make it difficult to find something that you might think should be easier.

Case in point: I was trying to set up an interrupt on a gpio for the IR signal in -- pretty basic need, right? But I couldn't for the life of me find any options on the GPIO configuration for something 'mode = input with interrupt', nor any options on the NVIC for 'EXTI xxx'. Reference Manual says they're there though (and it would be shocking if they weren't). At length I found that what you must do is go to the 'pinout' page, and set the pin not to be 'input', but rather 'exti input'. Then the options on the 'configuration' page for 'gpio' will reveal the additional options of 'input, interrupt on rising/falling', and then the options will be presented on 'nvic' to handle the interrupt for that line. Whee! There's other 'fun' to be found, but I'll keep this post short(er).

So the lesson is: if you can't find something you believe is there, just shake the dickens out of the app until you hear stuff rattling around, and then look to see if maybe that's the piece you were looking for.

-- "I beat my machine; it's a part of me, it's inside of me / I'm stuck in this dream it's changing me I am becoming..."