SparkFun Forums

[alim]

Hello everyone,
In one of my project, I am using interrupt and my microcontroller is Arduino Pro mini (5V, 16MHz) ATMega328. I am using both interrupts. Under each interrupt I am calling a function like following:

detachInterrupt(0);

A_SIG=1;
B_SIG=digitalRead(PinB); // PinB is another interrupt pin
if(B_SIG==0){
pulses++;
}
if(B_SIG==1){
pulses--;
}
attachInterrupt(0,A_FALL, FALLING);

I am interested if I can find how much time microcontroller will take to execute this part of the program. Because I have a feeling while executing this part of the program another interrupt happens and micrcontroller can not detect it. So, basically missing interrupts.

Thanks in advance if you can help.

[jremington]

Post ALL of your code, using code tags.

You don't need the detach and attach functions if you are using interrupts 0 and 1.

If you want to continue using attach and detach, the rest takes certainly less than 1 microsecond, but could be coded more efficiently, like this:

Code: Select all

if (digitalRead(PinB)) pulses--;
else pulses++;

or (much faster) read the interrupt pin by direct port access, assuming that PinB is INT1, PD3:

Code: Select all

if (PIND & 8) pulses--; //if PORTD, pin 3 is high
else pulses++;

[n1ist]

To see how long a bit of code takes, set a pin high just before the code in question and set it low right after. Then you can use a scope to see the width of the pulse.

[alim]

Wonderful, thank you both.