Timer1 goes too fast when used within a class

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1

Hi guys,

I would like to use a timer within a class.

I started trying to include TimerOne.h to my class header and then using Timer1.

MyClass.h:

#ifndef MYCLASS_H
#define MYCLASS_H

#include "TimerOne.h"

class MyClass {
    /* ATTRIBUTES */
    private:
        static MyClass *_instance;

    /* FUNCTIONS */
    public:
        MyClass(int useless);            
        ~MyClass() {
        }
    private:
        static void myIsr(void);
};

#endif  /* MYCLASS_H */

MyClass.cpp:

#include "MyClass.h"

MyClass* MyClass::_instance;            // Instantiate the static pointer

MyClass::MyClass(int useless) { 
    _instance = this;   
    Timer1.initialize(5000000);
    Timer1.attachInterrupt(myIsr);
}

void MyClass::myIsr(void) {
    Serial.println("Should be printed every 5s...");
}

myClass.ino:

#include <MyClass.h>

MyClass myObj(0);

void setup() {
  Serial.begin(9600);
}

void loop() {
}

The code compiles without any complaint.
During execution the message is printed on the screen but with a period (visibly) less than 5 s!
Trying to change the period seems not to have any effect.
What's wrong with that code?
Thank you in advance for your collaboration.

Regards,
Marco