STM32F4 EXTI level-sensitive interrupt problem

[gary239955_stm1]

Posted on February 26, 2013 at 10:53

I am using an STM32F4xx MCU and have configured it for external interrupts (EXTI) on PH2 (rising edge). Everything works OK until the odd occassion when the input to PH2 is left high at the end of the ISR. In this case the ISR does not seem to get called a second time. I understood that the EXTI works on both edge and level interrupts and that if the input is still active at the end of the ISR then the ISR would be called again. This does not seem to be happening. I cannot see anything in the Errata but then I'm not sure that I have the latest and the Errata PDFs seem to have disappeared from ST's redesigned website. Any help would be appreciated.

#exti

[Tesla DeLorean]

Posted on February 26, 2013 at 15:55

Does not work on levels, just edge(s)

10.2 External interrupt/event controller (EXTI) The external interrupt/event controller consists of up to 23 edge detectors for generating event/interrupt requests. Each input line can be independently configured to select the type (interrupt or event) and the corresponding trigger event (rising or falling or both). Each line can also masked independently. A pending register maintains the status line of the interrupt requests.