Posted on May 17, 2011 at 13:07Thanks for getting back to me on this. This is exactly what seems to be going wrong. When I try the code, without having the MCO clock output on pin A8, the interrupt worked just fine. I tried it on my board and and I just simulated an external interrupt by pulling the pin low. When I set and enable the MCO clock on pin A8 thats when the interrupt pending bit is also set and hence it keeps on going to the EXTI_9_5 IRQ. When I try to clear it, it sets again, repeatedly that it never gets out of the loop.
Is this only because I setting the EXTI to line 8? And both my clock on A8 and interrupt pin on B8 fall on the same line?
I have asked ST about this problem, don't know when or if they would get back to me on that.
I was wondering if I could accomplish the same task by using a PWM in input mode. The only problem is that I am not really measuring frequency but I do want a counter to start when the pin goes low and then in the IRQ i pull the pin high again and then when it goes low again, the counter would stop. Since it is not a simple frequency or pulse detection process I am not sure if this would work.
If you have any tips I would greatly appreciate it.
