//
// Analog Comparator Example
// By PEK '2006
//
// Compiler: GCC
// MCU: ATTiny26
// Clock: 1 MHz
//

#define F_CPU 1000000

#include <avr/io.h>
#include <avr/interrupt.h>

// Comparator ISR
ISR(ANA_COMP_vect)
{
   static uint8_t cntr = 0;

   PORTB = cntr++;
}

// Main
int main(void)
{
	// Setup Ports
	PORTB = 0x00;
	DDRB = 0xFF;	// PortB as output

	// Setup Analog Comparator
	ACSR = _BV(ACIE) | _BV(ACIS1) | _BV(ACIS0) | _BV(ACI);	// Interrupt when AIN0 > AIN1 (rising edge)

	sei();

	while(1);

	return 1;
}