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So I cannot play around with timer0 from the arduino ide?
Well, you can change the timing and PWM (capture/compare) values and stuff like that, but you can't provide your own interrupt service routine.
Actually I think that if you provide your own interrupt service routine for timer0 in the sketch then this will override the "standard" ISR. But then all timing functions will stop working, and other veird things can happen, so use caution.