![]() for a zero to two microsecond delay, simply return. per iteration, so execute it twice for each microsecond of the busy loop takes a half of a microsecond (8 cycles) of the function call yields a delay of approximately 1 us. for a zero or one-microsecond delay, simply return. of the function call yields a delay of approx 0.8 microsecond. for a zero or one-microsecond delay, simply wait 2 cycle and return. playing around with altering _us_ means we top out early on the max value we can pass. micros () works initially, but will start behaving erratically after 1-2 ms. 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. Only 13107 due to having to times 5, then divide by 2 :-( The documentation for attachInterrupt () says. Max we can pass on 8MHz -> 65535, on 16MHz its 32768 and for 20MHz its ![]() * Delay for the given number of microseconds ( 1% accurate of clock rate >20 ) I extended the delay loop, so i can use higher values passed in my own version of the code. As explained in the previous answers, your actual problem is not the accuracy of delayMicroseconds(), but rather the resolution of micros(). its *4 that value, hence the bit where 16383 is the max you can use., slower cpu's can use higher values, and faster even lower. hint ( the code multiplies the passed delay time, and thus over flows the unsigned int ) in the case of a 16MHz Uno. Rob Tilliart, has suggested some improvements to the call, to allow more accurate times, and I took his adears, and changed the code to allow a larger range. So to me, its quite right to use unsinged int as a value to call delayMicroseconds. On the boards from the Arduino Portenta family this function has a resolution of one microsecond on all cores. This number will overflow (go back to zero), after approximately 70 minutes. ![]() once over 1000 microsends, why not consider using delay() ? Returns the number of microseconds since the Arduino board began running the current program. The extra code to read, decrement and store the value would add a noticable amount of time to the function, its quite accurate in the normal range of what most uses of the function will use it for. That's unintuitive given that micros() returns an unsigned long, but presumably somebody somewhere thought that was a good idea. This means that regardless of whatever else may be going on inside the function, it would never be able to receive an argument greater than 65535 microseconds. However, if you dig into the code you will see that the signature of the function you're using is: void delayMicroseconds(unsigned int us) Here is where I am so far, I would really appreciate any help you can give.The Arduino API documentation is pretty useless about details like this because it doesn't bother to document the actual signature of these functions, which you need to know to use them correctly. I would like to use timer1 to handle this functionality, I have taken a look at:Ĭ:\Program Files (x86)\Arduino\hardware\arduino\cores\arduino\wiring.cĪs this is where the timing functions are implemented, but I just can't get it to work. I understand these are controlled by timer 0 and that why they are not working properly now. I need to use the timing functions such as delay() and micros(). I am using timer 0 and 2 to generate a PWM signal and this works fine. I am working on a project, using an Arduino Uno. Hey there, I am working on a project, using an Arduino Uno.
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