Wanting to use external interrupt to turn on internal led.

[SRees.2]

I am not wanting to use the HAL interface because I want to try and gain experience with the ARM bare metal programming. I have examples online and seem to be following them exactly but the led will not light up when a pin is pulled to ground. I measured the voltage on the pull up and do get voltage. The led will turn on if I put the code in the main while loop. I am using PB5 as the input.

[S.Ma]

Use the debugger ans put a breakpoint in the exti interrupt routine. Check exri works alone, then check led.control. view the he registerd, edit them manually live to get a feel and learn with fewer project rebuild cycles.

[SRees.2]

Hello,

Thanks so much for responding to my question. I've used the debugger and have checked the registers as I went through. All the registers are changing as expected with the exception of the NVIC. When I get to that point, I notice the SETENA and CLRENA both get a new value. When I pull the PB5 to zero volts nothing happens. If I use PB5 as a regular input and with the pull up and use an if statement, then the led will come on when the input is pulled to ground so I know I have my pin inputs and outputs set right. It's like the interrupt is just not enabled. Checking the PR5 bit it actually does change to 1 when I pull the PB5 low. Are there some additional settings or check boxes hidden away?

[S.Ma]

Older EXTI have only PR bit for falling edge. Newer ones have both. Without mentionning the STM32 code product name, answers will remain general.

[SRees.2]

It's a STM32F303RE. I wonder if the HAL files are causing a problem. I may try and start an empty project and add only needed files. When I go to the graphic interface to see available interrupts it actually shows only to available, the exti15-10. I tried that one and still nothing happens.

[S.Ma]

Read in detail the EXTI chapter in the refmanual. Now EXTI does not generate 1 unique interrupt vector per pin, it is by group of pins. Pin 0,1,2,3 are usually 1 vector per pin, not the others... you will need to poll the PR bit to find the source.

[SRees.2]

I only selected whichever interrupt I wanted with the IMR mask register. So only one pending interrupt will be triggered.