I often see something like this void UART2_IRQHandler(void) __irq, and I wonder why __irq is used when declaring interrupt handler, is it required or handler can work without it?
Electronic – Interrupt question ARM
armcinterruptsmicrocontroller
Related Solutions
The part that handles these things in a Cortex is the Nested Vectored Interrupt Controller (NVIC).
Question 1: When one interrupt handler is executed, will it be interrupted if another interrupt with the same priority occurs?
No, an interrupt will be acknowledged if it has a higher priority
Question 2: When one interrupt handler is executed, will it be interrupted if another interrupt with the lower priority occurs?
No, not while the interrupt handler is running.
I've found the issue. It turns out it is not possible to trigger off the same pin on multiple GPIO ports. I was overwriting my PA3 interrupt with a PB3 one.
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Best Answer
Basically, an interrupt service routine written in C is simply a function that takes no arguments and doesn't return anything
void someKindOfIsr(void).__irqis a C language extension for your compiler that is used to generate special entry and/or exit assembly instructions for handling interrupts. For instance, the return instruction may be different if you are returning from an interrupt rather than a simple function to clear some type of interrupt status register.Whether it is necessary or not depends on what ARM architecture you are working with. A quick way to find out if it is necessary for your platform is to examine the assembly produced both with and without the
__irqkeyword.Even if the listing file is exactly the same both with and without the
__irqkeyword, you may want to consider leaving the__irqkeyword in place for clarity and for portability to some future platform.