I’m looking at many examples that track millis() as a way of keeping time between events. For example, this code take from Tutorial: Getting Started with Spark.publish() . void loop() { unsigned long now = millis(); //Every 15 seconds publish uptime if (now-lastTime>15000UL) { la…

@damccull , you may want to do a forum search. Here is one topic I picked up from a search on "millis roll" [image] Micros() rolling over after 59.652323 seconds, not 71 minutes [SOLVED] Troubleshooting I’m running the following code: void setup (void) { Serial.begin(3…

That’s the beauty of using unsigned integers. If all of the numbers that you are dealing with are of the same unsigned long type (which it looks like they are), and it actually rolls over properly, aka integer overflow, not other method overflow (which millis() does… I believe micros() at least on…

I did see that post, but I didn’t see any examples in there of how to actually handle the rollover. Going back and looking again, I did find Micros() rolling over after 59.652323 seconds, not 71 minutes [SOLVED] , but now I don’t understand how it works. I understand that the function takes in 2 uns…

[image] damccull: From everything I understand about them, there should never be a negative value on an unsigned number. That's the charming thing about unsigned rollover. As @mumblepins already said, as long it is a propper binary rollover you can do smallValue - bigValue and you will get t…

Meh, thought I’d make an example online (using unsigned 8-bit for simplicity) http://cpp.sh/7wmr The way the C++ standard is defined, unsigned integers automatically (magically :smile: ) rollover on overflow, and ‘underflow’ , which is what takes place when you subtract a larger unsigned number fr…

Handling millis() rollover

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peekay123 July 7, 2015, 5:16pm 2

@damccull, you may want to do a forum search. Here is one topic I picked up from a search on "millis roll"

Topic		Replies	Views
Millis() and rollover tutorial Tutorials	32	20437	September 19, 2022
Micros() rolling over after 59.652323 seconds, not 71 minutes [SOLVED] Troubleshooting	47	14427	August 18, 2015
On off intervals, overflow safe Firmware	5	732	June 17, 2018
What in the world? Some randomness with millis() and subtraction Troubleshooting	9	2041	October 8, 2016
Comparing mills() Device OS	4	497	October 31, 2021

Handling millis() rollover

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