マイコン工作はじめの一歩（光センサブザーLEDマーカ)

// ATTINY26

// ADC0 : A-D Convertor Input

// PB3(OC1B) : Speaker

// PB5 : LED1 1:ON 0:OFF

#include <avr/io.h>

#define led_on() PORTB |= (1<<PB5)

#define led_off() PORTB &= ~(1<<PB5)

#define buz_on() PORTB |= (1<<PB3)

#define buz_off() PORTB &= ~(1<<PB3)

void wait(volatile long i)

{

    while (i-- > 0);

}

int adconv(void)

/* AD Convertor */

{

    int adata;

    ADCSR |= (1<<ADEN) | (1<<ADSC); // A-D convertor enable,

    ADMUX = (1<<ADLAR); /* ADLAR=1, ADC0 SingleEndedInput */

    while ( !(ADCSR & (1<<ADIF)) );

    adata = ADCH;

    ADCSR &=~(1<<ADIF);

    return adata;

}

int main(void)

{

    int adc, i;

    // Initialize I/O Port

    DDRB = (1<<PB3) | (1<<PB5);

    DDRA = ~(1<<PA0);

    while (1)

    {

        adc = adconv();

        led_on();

        for ( i = 0; i < (adc>>1); i++) {

            buz_on(); wait(adc);

            buz_off(); wait(adc);

        }

        led_off(); wait(adc * 100);

    }

    return 0;

}