#include <stdio.h>
#include <avr\io.h>
#include <avr\interrupt.h>
#include <avr\delay.h>

int uart_putchar(char c, FILE *unused);
int uart_getchar(FILE* f);
FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
FILE mystdin =  FDEV_SETUP_STREAM(NULL, uart_getchar, _FDEV_SETUP_READ);

int val;

char paused = 0;
int debounce_ctr = 0;

int ADC_get(uint8_t channel)
{
	ADMUX = (1<<REFS0);
	ADMUX |= channel;
	
	ADCSRA |= (1<<ADSC);
	loop_until_bit_is_set(ADCSRA, ADIF);
	
	return ADC;
}

void ADC_init(void)
{
	ADMUX = (1<<REFS0);
	ADCSRA = (1<<ADEN) | (1<<ADATE) | (1<<ADPS2) | (1<<ADPS1) | (1<<ADPS0); 
}

void USART_init(void)
{
	UCSRB = (1<<RXEN) | (1<<TXEN);
	UCSRC = (1<<URSEL) | (1<<UCSZ0) | (1<<UCSZ1);
	UBRRL = 103;	
}

void Timer1_init(void)
{
	OCR1A = 1000;
	TCCR1A = 0;
	TCCR1B = (1<<WGM12)|(1<<CS12)|(1<<CS10);
	TIMSK |= _BV(OCIE1A);
}

SIGNAL(SIG_OUTPUT_COMPARE1A)
{	
	uint8_t i;
	
	val = ADC_get(0);
	
	val -= 900;	//experimental noise level
	if(val < 0)
		val = 0;
	val = (int)((float)val/0.121f);	// linear adjust
	printf("\n%4d ", val);
	
	// at each clap (or noise spike), the leds pause
	if (!paused) {
		// this should be log
		if (val > 0) 	PORTC |= 0x01; else PORTC &= ~0x01;
		if (val > 128) 	PORTC |= 0x02; else PORTC &= ~0x02;
		if (val > 256)	PORTC |= 0x04; else PORTC &= ~0x04;
		if (val > 384)	PORTC |= 0x08; else PORTC &= ~0x08;
		if (val > 512)	PORTC |= 0x10; else PORTC &= ~0x10;
		if (val > 640)	PORTC |= 0x20; else PORTC &= ~0x20;
		if (val > 768)  PORTC |= 0x40; else PORTC &= ~0x40;
		if (val > 896)	PORTC |= 0x80; else PORTC &= ~0x80;
	}	
		
	if (val < 100 || val > 900) {
		if (debounce_ctr < 0) {
			paused ^= 1;
			printf("claps claps\n");
			// need to debounce a bit because the mic is adaptive
			debounce_ctr = 30;
		}			
	}
	debounce_ctr --;
}

int main(void)
{
	uint8_t key;
	uint8_t val = 1;
	long i;
	
	USART_init();
	
	stdin = &mystdin;
	stdout = &mystdout;

	cli();
	ADC_init();	
	Timer1_init();
	DDRC = 0xFF;
	sei();
	
	while(1);
	
    return 0;
}

int uart_putchar(char c, FILE *unused)      
{
	if (c == '\n')
		uart_putchar('\r', 0);
	loop_until_bit_is_set(UCSRA, UDRE);
	UDR = c;
	return 0;
}

int uart_getchar(FILE* f)
{
    char c;
    loop_until_bit_is_set(UCSRA, RXC);
    c = UDR;
    if(c=='\r')
         c='\n';
    uart_putchar(c,NULL); 
    return c;
}