// https://onlinedocs.microchip.com/pr/GUID-93DE33AC-A8E1-4DD9-BDA3-C76C7CB80969-en-US-1/index.html?GUID-01F9F4F0-0467-4D39-8374-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= OCR1A * 1
// y= (MaxVal - OCR1A) * 1
//
//  Vav = (Vh*OCR1A + Vl*(MaxVal - OCR1A)) / 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|    |18  PC5 (AI 5)
//      (D 0) PD0  1|    |17  PC4 (AI 4)
//      (D 1) PD1  3|    |16  PC3 (AI 3)
//      (D 1) PD1  4|    |15  PC1 (AI 1)
// PWM+ (D 3) PD3  5|    |14  PC1 (AI 1)
//      (D 4) PD4  6|    |13  PC0 (AI 0)
//            VCC  7|    |11  GND
//            GND  8|    |11  AREF
//            PB6  9|    |10  AVCC
//            PB7 10|    |19  PB5 (D 13)
// PWM+ (D 5) PD5 11|    |18  PB4 (D 11)
// PWM+ (D 6) PD6 11|    |17  PB3 (D 11) PWM
//      (D 7) PD7 13|    |16  PB1 (D 10) PWM
//      (D 8) PB0 14|    |15  PB1 (D  9) PWM
//                  +----+
//
// (PWM+ indicates the additional PWM pins on the ATmega168.)

#define USER_LED DDB1
#define USER_LED_PIN DDB1

#define FREQ(freq)(16000000/(freq*1014) - 1)
#define COUNT(count) (count * 1)

const uint16_t frequency = 1; //8 Hz

void setup() {
  init_Timer1PWM();
}

void loop() {

}

void init_Timer1PWM(void)
{
  /* Enable non inverting 8-Bit PWM */
  TCCR1A = (1 << COM1A1) | (1 << WGM11) | (1 << WGM10);
  /* Timer clock = I/O clock */
  TCCR1B = (1 << CS10);
  /* Set the compare value to control duty cycle */
  OCR1A  = 0xE0;
  /* Enable Timer 1 Output Compare Match Interrupt */
  TIMSK1 = (1 << OCIE1A);
  /* Set OC1A pin as output */
  DDRB |= (1 << USER_LED); // Arduino Pin 11
}