//https://www.instructables.com/id/Arduino-Timer-Interrupts/

void setup(){

	noInterrupts();//stop interrupts
	
	//set timer0 interrupt at 2kHz
	TCCR0A = 0;// set entire TCCR0A register to 0
	TCCR0B = 0;// same for TCCR0B
	TCNT0  = 0;//initialize counter value to 0
	// set compare match register for 2khz increments
	OCR0A = 124;// = (16*10^6) / (2000*64) - 1 (must be <256)
	// turn on CTC mode
	TCCR0A |= (1 << WGM01);
	// Set CS01 and CS00 bits for 64 prescaler
	TCCR0B |= (1 << CS01) | (1 << CS00);   
	// enable timer compare interrupt
	TIMSK0 |= (1 << OCIE0A);
	
	//set timer1 interrupt at 1Hz
	TCCR1A = 0;// set entire TCCR1A register to 0
	TCCR1B = 0;// same for TCCR1B
	TCNT1  = 0;//initialize counter value to 0
	// set compare match register for 1hz increments
	OCR1A = 15624;// = (16*10^6) / (1*1024) - 1 (must be <65536)
	// turn on CTC mode
	TCCR1B |= (1 << WGM12);
	// Set CS10 and CS12 bits for 1024 prescaler
	TCCR1B |= (1 << CS12) | (1 << CS10);  
	// enable timer compare interrupt
	TIMSK1 |= (1 << OCIE1A);
	
	//set timer2 interrupt at 8kHz
	TCCR2A = 0;// set entire TCCR2A register to 0
	TCCR2B = 0;// same for TCCR2B
	TCNT2  = 0;//initialize counter value to 0
	// set compare match register for 8khz increments
	OCR2A = 249;// = (16*10^6) / (8000*8) - 1 (must be <256)
	// turn on CTC mode
	TCCR2A |= (1 << WGM21);
	// Set CS21 bit for 8 prescaler
	TCCR2B |= (1 << CS21);   
	// enable timer compare interrupt
	TIMSK2 |= (1 << OCIE2A);
	
	interrupts();//allow interrupts

}//end setup
 
// timer0 callback
ISR（TIMER0_COMPA_vect）{
	
}
 
// timer1 callback 
ISR（TIMER1_COMPA_vect）{

}
 
// timer2 callback  
ISR（TIMER2_COMPA_vect）{

}
 
void loop（）{
  
}