main.c

/*
 * LCD + INT + TIMER + ADC
 
 Ports:
 - PORTB: OC0 usage
 - PORTC: LCD usage (defined in lcd4.h, modified via `#define`)
 - PORTD: using INT1
 - PORTE: LED-GREEN output, using PE1.
 - PORTF: ADC purpose.
 
 Interrupt:
- Enabled
- INT1, falling edge.

 Timer:
 - Fast PWM, 1024.
 - Timer0 overflow interrupt enabled
 
 ADC:
 - Interrupt enabled
 
 */ 

#include <xc.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/delay.h>
#include <stdio.h>
#include "lcd4.h"


#define cbi(REG8, BITNUM) REG8 &= ~(_BV(BITNUM))
#define sbi(REG8, BITNUM) REG8 |= _BV(BITNUM)

unsigned volatile char state = 0;
unsigned volatile int ovf_count = 0;

ISR(TIMER0_OVF_vect) {
	if (ovf_count > 9) {
		ovf_count = 0;
		
		if (state & 0x02) {
			PORTE ^= 0x02;
		} else { 
			PORTE = 0x00;
		}
		
	} else ovf_count++;
	
	PORTE ^= 0x02;
}

ISR(INT1_vect) {
	state ^= 0x01;
	if (state & 0x01) { 
		TCCR0 &= 0xC8; // 
		TIMSK = 0x00;
		PORTE = 0x00;
		writeString_lcd4(0, 1, "Listening Stopped");
	} else {
		TCCR0 |= 0x37;
		TIMSK = 0x01;
	}
}

long adc_result;
int adc_volt;
char msg[20];
ISR(ADC_vect) {
	adc_result = ADC;
	adc_volt = adc_result * 5000 / 1023;
	
	sprintf(msg, "val: %d.%03dv", adc_volt/1000, adc_volt%1000);
	writeString_lcd4(0, 1, msg);
}

int main(void)
{
	
	// PORTB: Timer OC0 usage
	DDRB = 0x10;
	
	// PORTC: LCD Usage
	PORTC = 0xff;
	
	// PORTD: using INT1 input
	DDRD = 0x00; PORTD = 0x02;
	
	// PORTE: LED-GREEN output, using PE1.
	DDRE = 0x02; PORTE = 0x02;
	
	// PORTF: ADC purpose.
	DDRF = 0x00;
	
	// Initialize LCD
	DDRC = 0xff;
	init_lcd4();
	writeString_lcd4(0, 0, "Interrupt Mode");
	
	// Initialize INT1 interrupt
	EIMSK = 0x02; // INT1
	EICRA = 0x08; // falling-edge
	
	// Initialize Timer
	TCCR0 = 0x20 // COM01 (HOW)
			| 0x48 // Fast PWM
			| 0x07; // 1024 clocks
	TIMSK = 0x01; // Timer/Counter0 Overflow Interrupt Enable
	TCNT0 = 0x00; // reset TCNT0
	OCR0 = 0x7f; // 50% compare
	
	// Initialize ADC
	ADCSRA = (1 << ADEN) | (1 << ADIE) | (1 << ADPS2) | (1 << ADPS1);
	ADMUX = 0x01; // using on ADC1.
	
	
	sei(); // set interrupt
	
    while(1) {
		ADCSRA |= (1 << ADSC);
		_delay_ms(400);
	}
}