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

const char out_sign[10] = {0b00111111, 0b00000110, 0b01011011, 0b01001111, 0b01100110, 0b01101101, 0b01111101, 0b00000111, 0b01111111, 0b01101111};
const float capture_time = 0.008192, a1=-202.7755, b1=10464.162, c1=1384729.4, d1=179769.39;
const float a2=-8006.5664, b2=79823.682, c2=1918082.9, d2=287765.3;

int N = 0;


INTERRUPT(SIG_OUTPUT_COMPARE0)
{
N = 80;
}


float _get_opt_from_frequ (float frequ)
{
float light;
float a=a1, b=b1, c=c1, d=d1;
if (frequ>1349000) 
	{
	a=a2;
	b=b2;
	c=c2;
	d=d2;
	}
light=a+b/(1+square((frequ-c)/d));
return light;
}


void LED_OUT_4 (float out) 
{
char dot=0, dig=0;
float whole, fract;
if (out>9999) 
	{
	dot = 7;
	out/=10;
	}
fract=modf(out,&whole);
if (whole<10) 
	{
    dot=3;
    }
        else if (whole<100) 
            {
            dot=2;
            out=out/10;
            }
                else if (whole<1000) 
                    {
                    dot=1;
                    out=out/100;
                    }
                        else 
                            {
                            out=out/1000;
                            };
fract=modf(out,&whole);
dig=out_sign[(int)whole];
if (dot==3) dig=dig|0x80;
PORTC=0x01;
PORTA=dig;
whole=fract*10;
fract=modf(whole,&whole);
dig=out_sign[(int)whole];
if (dot==2) dig=dig|0x80;
PORTC<<=1;
PORTA=dig;
whole=fract*10;
fract=modf(whole,&whole);
dig=out_sign[(int)whole];
if (dot==1) dig=dig|0x80;
PORTC<<=1;
PORTA=dig;
whole=fract*10;
fract=modf(whole,&whole);
if (fract>=0.5) whole++;
dig=out_sign[(int)whole];
if (dot==7) dig=dig|0x80;
PORTC<<=1;
PORTA=dig;
}


int main (void)
{
float frequ = 0;
float light = 0;
DDRA = 0xFF;//Set I/O ports
DDRC = 0x0F;
TCCR0=0x05;//Set timer0
OCR0=0x60;
TIMSK=0x01;
TCCR1B=0x46;//set timer1 to capture a rising edge
sei();//set global interrupt
while(1)
	{
	if (N!=7)
		{
		frequ=N/capture_time;//computing frequency
		light=_get_opt_from_frequ(frequ);//computing light
		N=7;
		}
	light=TCNT1L;
	if (frequ==0) light=0;
	LED_OUT_4(light);//output light
	PORTA=0x00;
	}
}