Hi,

I'd like to use interrupt routine to monitor an input signal, for example:

if (input)

    led =1;

 else

     led = 0;

I try to use both rising edge and falling edge trigger to flag a high or low (assuming input is low to begin with):

t1.rise(&trigger1);

t1.fall(&trigger2);



void trigger1()

{

    input = 1;

}



void trigger2()

{

   input = 0;

}

Somehow it's not very reliable, probably due to bouncing. Is there a better level sensitive interrupt solution?

I usually set something like  10ms timer; which I keep resetting; and if it goes through you know the last value was stable for at least 10ms.

t1.rise(&trigger); t1.fall(&trigger); void trigger() { input = XX; resetTimer(10ms) };

onTimeOut() { // We're 10ms stable - so trust value in input };

If it is more critical; consider shifting the value into an 8 or 16 bit integer - so you can look at its history and take it from there. (And you reset the history to the current value once it is stable for your timeout period).

interruptTest2

I did some de-bouncing as shown in the attached code (which I copied from http://mbed.org/forum/mbed/topic/716/?page=1#comment-3544)

The "counter" inside still keeps on increasing, which means the program catches more rising edge than falling edge. That's not going to work as a level sensitive trigger.

And here is another attempt. Am I allowed to do this:

InterruptIn input(p8);

DigitalIn check(p8);

which use p8 both in InterruptIn and DigitalIn instance.

interruptTest

Hi Zhe, just to let you know I have the same problem. I posted a similar problem about this in this thread. I am monitoring an IN/OUT port and am having the exact same problem in which i am getting one too many rising edge triggers.