// https://onlinedocs.microchip.com/pr/GUID-93DE33AC-A8E1-4DD9-BDA3-C76C7CB80969-en-US-2/index.html?GUID-02F9F4F0-0467-4D39-8374-F896EB1E6C87



// Vh: Output Voltage high level
// Vl: Output Voltage low level
// Vav: Average Output Voltage level
// x: Duty cycle high level
// y: Duty cycle low level

// Vav = (Vh*x + Vl*y) / (x + y)
// where,
// x= OCR2A * 2
// y= (MaxVal - OCR2A) * 2
//
//  Vav = (Vh*OCR2A + Vl*(MaxVal - OCR2A)) / MaxVal
//

// On the Arduino board, digital pins are also used
// for the analog output (software PWM).  Analog input
// pins are a separate set.

// ATMEL ATMEGA8 & 168 / ARDUINO
//
//                  +-\/-+
//            PC6  1|    |28  PC5 (AI 5)
//      (D 0) PD0  2|    |27  PC4 (AI 4)
//      (D 1) PD1  3|    |26  PC3 (AI 3)
//      (D 2) PD2  4|    |25  PC2 (AI 2)
// PWM+ (D 3) PD3  5|    |24  PC1 (AI 1)
//      (D 4) PD4  6|    |23  PC0 (AI 0)
//            VCC  7|    |22  GND
//            GND  8|    |21  AREF
//            PB6  9|    |20  AVCC
//            PB7 10|    |19  PB5 (D 13)
// PWM+ (D 5) PD5 11|    |18  PB4 (D 12)
// PWM+ (D 6) PD6 12|    |17  PB3 (D 11) PWM
//      (D 7) PD7 13|    |16  PB2 (D 10) PWM
//      (D 8) PB0 14|    |15  PB1 (D  9) PWM
//                  +----+
//
// (PWM+ indicates the additional PWM pins on the ATmega168.)

#define USER_LED DDB5


#define FREQ(freq)(16000000/(freq*1024) - 1)
#define COUNT(count) (count * 2)

const uint16_t frequency = 2; //8 Hz

void setup() {
  Serial.begin(115200);
	DDRB |= (1 << USER_LED);
	init_Timer1InputCaptureInterrupt();	
}

void loop() {

}

void init_Timer1InputCaptureInterrupt(void)
{
	/* Timer clock = I/O clock / 64 */
	TCCR1B = (1<<CS11)|(1<<CS10);
	/* Clear ICF1. Clear pending interrupts */
	TIFR1   = 1<<ICF1;
	/* Enable Timer 1 Capture Event Interrupt */
	TIMSK1  = 1<<ICIE1;
} 

ISR (TIMER1_CAPT_vect)
{
	Serial.println("d");
	/* Toggle a pin after input capture */
	PORTB  ^= (1 << USER_LED);
	/* Clear counter to restart counting */
	TCNT1 = 0;
}