/*
	模擬比較器測試程序 
	main.c
	MCU:ATMega8
	
	芯藝 2004-09-16
*/

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

#define uchar unsigned char

#define SET_RED_LED PORTB&=0XFD //PB1接紅色發光管
#define CLR_RED_LED PORTB|=0X02

#define SET_YEL_LED PORTB&=0XFE	//PB0接黃色發光管
#define CLR_YEL_LED PORTB|=0X01

//模擬比較器中斷函數
SIGNAL(SIG_COMPARATOR)
{
	if(ACSR & _BV(ACO))
	{
		SET_YEL_LED;
		CLR_RED_LED;
	}
	else
	{
		CLR_YEL_LED;
		SET_RED_LED;
	}
}

int main(void)
{
	DDRB=0X03;
	PORTB=0X03;

	//模擬比較器上下均觸發中斷 ACIS1=ACIS0=0
	//中斷允許 ACIE=1
	ACSR=_BV(ACIE);

	sei();
	
	//AIN0:正極 AIN1:負極  AIN0腳上的電壓高于AIN1上電壓時AC0=1
	if(ACSR & _BV(ACO))
	{
		SET_YEL_LED;
		CLR_RED_LED;
	}
	else
	{
		CLR_YEL_LED;
		SET_RED_LED;
	}

	while(1);
}