Global variables: loosing the value

Projects Programming
17

I suspect the problem is that you're overflowing the bounds of one of those arrays. Here is one place you do it - I haven't checked for others:

for (int i = 0; i <= MaxTimers; i++)

The '<=' should be a '<'.

I also noticed this code:

  int DiffMillis;
  unsigned long ActualMills = millis();
  if (LastTimeLoop > ActualMills)
  {
    // questo ? il valore massimo di millisecondi :4,294,967,295 
    DiffMillis = 4294967295 - LastTimeLoop + ActualMills;
  }
  else
  {
    DiffMillis = ActualMills - LastTimeLoop;
  }

Please don't do that. I don't know whether it actually copes correctly with timer overflow, but it's a horrible way to do it. If you want to know how many milliseconds have elapsed between two calls to millis(), do it like this:

unsigned long startTime = millis();
// do stuff
unsigned long elapsed = millis() - startTime;

I assume you can generalise that approach to do whatever it is you're trying to do here. The important details in order for timer overflow to be handled correctly are:

  • Use unsigned long
  • Use subtraction not addition