If that's the case, you need a faster clock frequency because you've hit the limit of what your microcontroller can handle. Then code flow jumps back to loop()?Īnd when the timer starts counting again? using a timer interrupt,where the on/off time is based on the input voltage applied to ADC input 0 of the microcontroller. Treat interrupts as being completely unpredictable from the perspective of your main code flow.Īfter the interrupt is fired, all the code in the interrupt is run. So by the time the code raches setup, the timer is already running.Ĭan you figure out how many instructions will be executed in the loop function, before a call to a timer interrupt is performed, for the given frequency you have specified? In the case of a premade core like Arduino, there is an init function that is run before setup. When the code explicitly starts the timer. In that case, would it be wise to put code that you would generally put inside the loop(), inside a timer interrupt?īut when does tghe timer starts counting down? If you set up the timer interrupt frequnecy too high, do you run the risk of having code in you loop functin not run at all? (If, for example, you have lots of code inside the loop()). Then code flow jumps back to loop()? And when the timer starts counting again? At the same time the code jumps to loop? But when does tghe timer starts counting down? When you first jump to loop? Can you figure out how many instructions will be executed in the loop function, before a call to a timer interrupt is performed, for the given frequency you have specified?Īfter the interrupt is fired, all the code in the interrupt is run. Each of the timers has a counter that is incremented on each tick of the timers clock. Obvisouly the arduino runs the setup function first. 1.The Uno has three timers called timer0, timer1, and timer2. Emulates timer interrupts by creating a dynamic list of periodically called callback functions. My question is how code flows in general. Allows for timer interrupts on various platforms. You can do this via the TC_SetRC(tc, channel, rc) function. In other words, you can specify the frequency of the intterupts. In the Arduino DUE, you can specify the timer value. I know that the timer counts up to a certain value, then generates an interrupt. I tested the code in Tinkercad and now it seems to work.My platform is the Arduino DUE. You have to clear the a variable in your else statement to it starts counting again. At least, the Timer vector function takes more than 64 clock cycles itself. It counts 1 to 100 one time, then starts incrementing and printing b. begingroup The other thing I see, is that the timer interrupt is being called every 64 clock cycles (CS20 and CS21 64 prescaling and OCR1A 1), and maybe is being triggered when the micro is 'busy' doing the ADC interrupt function. int a = 0 Įdit 2: Actually, your code don't do what you want. probably you have to define then out of the loop function.Įdit: In my example I declared the variables inside setup() function, as the guy who comment my answer said, it declares a variable only in the scope of that function, you actually need to declare it out of any function. You're defining a and b on the beginning of the loop(), the loop function is called every time, so your a and b are cleared every time.
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