The millis() function is handy for timing things with the Particle Photon (and Electron, and Core). It executes very quickly and has a good resolution (milliseconds). From the manual: Returns the number of milliseconds since the device began running the current program. This number will overflow (…

Can you explain why the difference between two unsigned short is not greater than or equal to zero? In the code which is posted above, why is the condition (b - a > 0) false?

[image] dheerajdake: In the code which is posted above, why is the condition (b - a > 0) false? What do you mean? in your example the result of (b-a) and (d-c) are both greater than zero. google "C or C++ usual arithmetic conversions"

No. If you execute this code, the output is Choice 2 only. Please take a moment to read my earlier comment. Thanks Dheeraj

Thanks for posting this. I was thinking of doing something similar, because many times i see people using millis(), and often wonder thinking based on their code snippet they are not considering the effects of the rollover.

Tried it on gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.4) Apple LLVM version 9.0.0 (clang-900.0.38) Target: x86_64-apple-darwin16.7.0 ARM GCC 541 Particle cloud compiler All results were same.

This is C integer promotion from short to int. The assumption built-in to the language is that doing arithmetic on int and uint is faster than doing it on the smaller types. This stack overflow has some good info and pointers: [dayuloli] Why must a short be converted to an in…

why 1000? so for all the negative numbers will be 1000? what would happen in the second, third…loop (all will be negative, so all will be 1000)? so it would not reach the interval time? I want to run my code for 12 months, will it work? #define publish_cycle 30000 unsigned long lastPublish = 0; …

This question could also have been asked in your own thread instead of just dropping your code there without further comment - particularly not answering any of the questions asked. That's not really appreciated by people trying to help in their little spare time [image] Particle …

@rickkas7 : Is the rollover of millis() an issue while using elapsedMillis.h (and f.e. elapsedMillisDemo.cpp) from the library? if so, please add a note to the .cpp or change the code of .h please, a great help for newbies, else they are wondering why things stop running after a certain time, and tur…

Millis() and rollover tutorial

Tutorials

dheerajdake October 25, 2017, 7:42pm 15

Tried it on

gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.4)
Apple LLVM version 9.0.0 (clang-900.0.38)
Target: x86_64-apple-darwin16.7.0
ARM GCC 541
Particle cloud compiler

All results were same.

Check and correct based of sensor many sensors- logic structure

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Millis() and rollover tutorial

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