![]() If you run this code you will see that the Run Other Code is not printed out for 10sec after the startup, but after the led is turned off (ledOn equals false) then is printed out very fast as loop() is called over and over again. In the sketch above, the first time loop() is called, the delay(10000) stops everything for 10secs before turning the led off and continuing. This is where most of you code goes, reading sensors sending output etc. Once setup() is finished, Arduino calls the loop() method over and over again. In the setup() method, which Arduino calls once on starting up, the led is turned on. ![]() LedOn = false // prevent this code being run more then once PinMode(led, OUTPUT) // initialize the digital pin as an output. Here is how NOT to code a delay in a sketch. This instructable is also on-line at How to code Timers and Delays in Arduino Download SafeString from the Arduino Library manager or from its zip file The millisDelay class is now part of the SafeString library V3+. The millisDelay library provides functionality delays and timers, is simple to use and easy to understand for those new to Arduino. If you already understand why you should not use delay() and are familiar with Arduino, the importance of using unsigned longs, overflow and unsigned subtraction, then you can just skip to Using the millisDelay library (Step 4) There are also examples of single-shot and repeating timers. The second is an example of code the works and the third is an example of using the millisDelay library to simplify the code. The first one is an example of how you should NOT write the code. Here are a number of simple sketches each of which turn a Led on when the Arduino board is powered up (or reset) and then 10sec later turns it off. The companion tutorial Simple Multi-tasking in Arduino covers all the other necessary steps. This is the first step to achieving simple multi-tasking on any Arduino board. ![]() This page explains in a step by step way how to replace Arduino delay() with a non-blocking version that allows you code to continue to run while waiting for the delay to time out. However replacing delays requires some care. Using delay() causes your system to be stuck while waiting for the delay to expire. If you are just looking for info on how to use the millisDelay library jump to Using the millisDelay library (Step 4) If you just want to flash an output pin On and Off at a given rate jump to PinFlasher (Step 6) Added Freeze/Pause delay exampleĪlso see Arduino For Beginners – Next Steps How to write Timers and Delays in Arduino (this one) Safe Arduino String Processing for Beginners Simple Arduino Libraries for Beginners Simple Multi-tasking in Arduino Arduino Serial I/O for the Real World The instructable Simple Multi-tasking in Arduino on Any Board covers all the other necessary steps.ĥth May 2019 update: Renamed isFinished() to justFinished(), as it only returns TRUE once just after the delay finishes. Download SafeString from the Arduino Library manager or from its zip fileĥth Sept 2019 update: Removing delay() calls is the first step to achieving simple multi-tasking on any Arduino board. So even if you lose two to Timer 0, you should have 5 outputs left (it looks like the "B" side of Timer 1 and Timer 4 share the same pin).20th Dec 2021 update: added PinFlasher class and example (included in SafeString library V4.1.13+)Ħth Jan 2020 update: The millisDelay class is now part of the SafeString library V3+. Provide 8-bit PWM output with the analogWrite() function. PWM, fast PWM or something else) and whether each output should be the same or different frequencies. You could get a more detailed answer if you clarified what the exact frequency you want is, what mode (eg. For more details see the ATmega32U4 datasheet. I have a page about timers which is for the Atmega328P, but the Leonardo timers have a lot in common with that. A given timer can only be in one mode at a time, which limits a bit what its two output ports can be doing at one time. Each timer has two "ports" associated with it, so you can have different outputs - up to a point - for each timer. A bit would depend on whether you want them to all have the same frequency (but maybe with different duty cycles) or different frequencies. You can get a wide range of frequencies by changing the prescalers and other factors. Timers 1 and 3 are 16-bit timers, and Timer4 is a 10 bit timer. The ATmega32U4 on the Leonardo has 4 timers, named Timer0, Timer1, Timer3 and Timer4.
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