![]() ![]() ![]() Since delay() requires interrupts to work, it will not work if called inside an ISR. millis() relies on interrupts to count, so it will never increment inside an ISR. If your sketch uses multiple ISRs, only one can run at a time, other interrupts will be executed after the current one finishes in an order that depends on the priority they have. Generally, an ISR should be as short and fast as possible. An ISR cannot have any parameters, and they shouldn't return anything. If the interruption is too long, maybe the motor reached the end of its track but you can’t stop its rotation yet till the interruption is not over, so that will result into something bad.ISRs are special kinds of functions that have some unique limitations most other functions do not have. So what if you are controlling the position of a step motor. On the same reason, if an interruption is too long, remember that during interruption, the rest of the code is on pause. In this way, the interruption is as fast as possible. So what I recommend you is to just change values of variables in the ISR routine and then, let all the rest of calculations, decisions and so on, to be made in the void loop. In conclusion, we must make the ISR routine as fast as possible. That means if one pins triggers an interruption and in just a few moments a different pin triggers another interruption while we are still running the first interruption routine, the second interruption won’t trigger. When we are inside an interruption, the rest of interruptions are on pause. Part 6.2 - Have in mind (2 PCINT from same port)Īnother thing to have in mind. Once these lines are executed, the interruption flag goes back to "1" and these lines of code won’t run again till another interruption of pin D5 is triggered. Between the brackets we add our interruption code. This it the interruption loop for port D. So in the code, after or before the void loop, we add the lines below. So we have to add the code for the PCINT2_vect ISR. To sum it all uo, in the example before, we have set digital pin D5 to trigger interruption. We now have all the elements that we need to explain how pin change interrupts work.
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